Accident and Serious Incident Reports: AW
Accident and Serious Incident Reports: AW
Definition
A selection of reports relating to accidents and serious incidents which involved Airworthiness as a factor.
The reports are listed below in two groups, the first of which lists the event according to the system affected. The second group identifies events in which Airworthiness was a contributing factor and lists the events by category.
Group 1 - Systems
Airframe
On 8 July 2019, a loud bang was heard following intermediate flap selection on a Boeing 747-400F making an approach to Harare and a concurrent uncommanded right roll was countered with left aileron. The flight was completed without further event but a post-flight inspection found part of the inboard section of the right wing flap assembly was missing and the right fuselage impact-damaged in several places. The missing flap section measuring 3.7 metres by 0.6 metres was recovered with detachment attributed to undetected fatigue cracking already present at component installation. A long history of problems with 747 flaps was noted.
On 23 February 2020, a Bombardier Challenger 605 making a flapless landing after a system failure during descent briefly lost control when reverse thrust selection after a normal touchdown was followed by the aircraft becoming airborne before stick push activation was followed by a hard second touchdown. Structural and abrasion fuselage damage was caused. The Investigation attributed the flap failure to corrosion within the specified maintenance inspection interval and the brief loss of control during landing to a combination of inadequate crew preparation for the landing and the fact that simulator replication of aircraft handling did not correspond to reality.
On 1 April 2011, a Southwest Boeing 737-300 climbing through FL340 experienced a sudden loss of pressurisation as a section of fuselage crown skin ruptured. A successful emergency descent was made with a diversion to Yuma, where the aircraft landed half an hour later. Investigation found that the cause of the failure was an undetected manufacturing fault in the 15 year-old aircraft. One member of the cabin crew and an off duty staff member who tried to assist him became temporarily unconscious after disregarding training predicated on the time of useful consciousness after sudden depressurisation.
On 29 December 2010 an American Airlines Boeing 757-200 overran the landing runway at Jackson Hole WY after a bounced touchdown following which neither the speed brakes nor the thrust reversers functioned as expected. The subsequent investigation found that although the speed brakes had been armed and the deployed call had been made, this had not occurred and that the thrust reversers had locked on transit after premature selection during the bounce. It was noted that had the spoilers been manually selected, the thrust reverser problem would not have prevented the aircraft stopping on the runway.
On 23 September 2017, a large wing-to-body fairing panel confirmed to have dropped from a Boeing 777-200 passing over the centre of Osaka after takeoff off from Kansai hit and significantly damaged a moving vehicle. The Investigation found that the panel involved had a sufficient history of attachment bracket failures for Boeing to have developed an improved thicker bracket for new-build aircraft which had then been advised as available as a replacement for in-service 777-200 aircraft in a Service Letter which KLM had decided not to follow. Although some incorrect bracket attachment bolts were found, this was not considered contributory.
On 15 October 2015 a Boeing 747-300 experienced significant vibration from one of the engines almost immediately after take-off from Tehran Mehrabad. After the climb out was continued without reducing the affected engine thrust an uncontained failure followed 3 minutes later. The ejected debris caused the almost simultaneous failure of the No 4 engine, loss of multiple hydraulic systems and all the fuel from one wing tank. The Investigation attributed the vibration to the Operator's continued use of the engine without relevant Airworthiness Directive action and the subsequent failure to continued operation of the engine after its onset.
On 6 April 2016, a BAe ATP partly left the side of the runway soon after touchdown, regaining it after 155 metres before completing its landing roll. It sustained damage rendering it unfit to continue flying but this was not noticed until five further flights had been made. Investigation attributed the excursion to lack of pilot response to unexpected beta range power and the continued flying to the aircraft Captain's failure to ensure proper event recording, accurate operator notification or a post-excursion engineering inspection of the aircraft. Systemic inadequacy in safety management and culture at the operator was identified.
On 14 December 2016, soon after a Bombardier DHC8-400 took off from Manchester, an unfastened engine access panel detached and struck and damaged the aircraft's vertical stabiliser before falling onto and alongside the departure runway. The Investigation found the panel had been left unsecured after routine overnight maintenance which required it to be opened and that this condition had not then been detected during the pilot-performed pre-flight external check. An identical event was found to have occurred to the same aircraft a month earlier. The Operator-provided pilot training on pre departure inspections was found to be inconsistent.
On 5 March 2013, the aft-stationed cabin crew of an Airbus A330-300 being operated by Lufthansa on a scheduled international passenger flight from Chicago O'Hare to Munich advised the flight crew after the night normal visibility take-off that they had heard an unusual noise during take-off. Noting that nothing unusual had been heard in the flight deck and that there were no indications of any abnormal system status, the Captain decided, after consulting Company maintenance, that the flight should be completed as planned. The flight proceeded uneventfully but on arrival in Munich, it became clear that the aircraft had sustained substantial damage due to a tail strike on take-off and was unfit for flight.
On 28 August 2006, a Hawker 800 collided with a glider at 16,000 feet in Class 'E' airspace. The glider became uncontrollable and its pilot evacuated by parachute. The Hawker was structurally damaged and one engine stopped but it was recovered to a nearby airport. The Investigation noted that the collision had occurred in an area well known for glider activity in which transport aircraft frequently avoided glider collisions using ATC traffic information or by following TCAS RAs. The glider was being flown by a visitor to the area with its transponder intentionally switched off to conserve battery power.
Air Conditioning and Pressurisation
On 13 July 2018, a Boeing 737-800 cruising at FL370 at night experienced a sudden rapid depressurisation. An emergency descent to FL 090 followed but the cabin altitude was not manually controlled and after the cabin pressure had risen to that equivalent to 7000 feet below sea level, immediate equalisation of cabin and actual altitudes resulted in a second sudden depressurisation. Diversion to Frankfurt Hahn was completed without further event. The first depressurisation had resulted from a transient and rare pressure controller malfunction but passenger injuries were considered attributable to a complete absence of pressurisation control during the emergency descent.
On 1 June 2019, a Boeing 787-8 lost all cabin air conditioning after both packs failed less than an hour from its destination, Narita. When the Cabin Altitude reached 10,000 feet, the descent already commenced was completed as an emergency descent and the flight thereafter was without further event. The Investigation found that although an amended non normal procedure restricting pack resets to a maximum altitude of 35000 feet had been issued almost two months earlier, it was still “under review” at the operator which has since amended their procedures for assessing manufacturer communications which have operational safety implications.
On 3 August 2018, smoke appeared and began to intensify in the passenger cabin but not the flight deck of an Airbus A319 taxiing for departure at Helsinki. Cabin crew notified the Captain who stopped the aircraft and sanctioned an emergency evacuation. This then commenced whilst the engines were still running and inadequate instructions to passengers resulted in a completely disorderly evacuation. The Investigation attributed this to inadequate crew procedures which only envisaged an evacuation ordered by the Captain for reasons they were directly aware of and not a situation where the evacuation need was only obvious in the cabin.
On 19 October 2012, a Jet2-operated Boeing 737-800 departing Glasgow made a high speed rejected take off when a strange smell became apparent in the flight deck and the senior cabin crew reported what appeared to be smoke in the cabin. The subsequent emergency evacuation resulted in one serious passenger injury. The Investigation was unable to conclusively identify a cause of the smoke and the also- detected burning smells but excess moisture in the air conditioning system was considered likely to have been a factor and the Operator subsequently made changes to its maintenance procedures.
On 5 March 2011, a Finnair Airbus A320 was westbound in the cruise in southern Swedish airspace after despatch with Engine 1 bleed air system inoperative when the Engine 2 bleed air system failed and an emergency descent was necessary. The Investigation found that the Engine 2 system had shut down due to overheating and that access to proactive and reactive procedures related to operations with only a single bleed air system available were deficient. The crew failure to make use of APU air to help sustain cabin pressurisation during flight completion was noted.
On 5 March 2018, the crew of an Airbus A320 in descent towards Karachi observed a slow but continuous drop in cabin pressure which eventually triggered an excessive cabin altitude warning which led them to don oxygen masks, commence an emergency descent and declare a PAN to ATC until the situation had been normalised. The Investigation found that the cause was the processing of internally corrupted data in the active cabin pressure controller which had used a landing field elevation of over 10,000 feet. It noted that Airbus is developing a modified controller that will prevent erroneous data calculations occurring.
On 21 February 2017, an Airbus A320 despatched with the APU inoperative experienced successive failures of both air conditioning and pressurisation systems, the second of which occurred at FL300 and prompted the declaration of a MAYDAY and an emergency descent followed by an uneventful diversion to Alicante. The Investigation found that the cause of the dual failure was likely to have been the undetectable and undetected degradation of the aircraft bleed air regulation system and whilst noting a possibly contributory maintenance error recommended that a new scheduled maintenance task to check components in the aircraft type bleed system be established.
On 12 July 2018, a Boeing 737-800 was climbing through FL135 soon after takeoff from Sydney with First Officer line training in progress when the cabin altitude warning horn sounded because both air conditioning packs had not been switched on. The Captain took control and descended the aircraft to FL100 until the situation had been normalised and the intended flight was completed. The Investigation noted that although both pilots were experienced in command on other aircraft types, both had limited time on the 737 and concluded that incorrect system configuration was consequent on procedures and checklists not being managed appropriately.
On 3 December 2017, an Embraer E190 en-route at FL310 was already turning back to Helsinki because of a burning smell in the flight deck when smoke in the cabin was followed by smoke in the flight deck. A MAYDAY was declared to ATC reporting “fire on board” and their suggested diversion to Turku was accepted. The situation initially improved but worsened after landing prompting a precautionary emergency evacuation. The Investigation subsequently attributed the smoke to a malfunctioning air cycle machine. Issues with inaccessible cabin crew smoke hoods and with the conduct and aftermath of the evacuation were also identified.
On 23 August 2017, a Boeing 767-400ER which had departed Zurich for a transatlantic crossing experienced a problem with cabin pressurisation as the aircraft approached FL 100 and levelled off to run the applicable checklist. However, despite being unable to confirm that the pressurisation system was functioning normally, the climb was then re-commenced resulting in a recurrence of the same problem and a MAYDAY emergency descent from FL 200. The Investigation found that an engineer had mixed up which pressurisation system valve was to be de-activated before departure and that the flight crew decision to continue the climb had been risky.
Autoflight
On 5 April 2019, a Boeing 737-500 crew declared an emergency shortly after departing Madrid Barajas after problems maintaining normal lateral, vertical or airspeed control of their aircraft in IMC. After two failed attempts at ILS approaches in unexceptional weather conditions, the flight was successfully landed at a nearby military airbase. The Investigation found that a malfunction which probably prevented use of the Captain’s autopilot found before departure was not documented until after the flight but could not find a technical explanation for inability to control the aircraft manually given that dispatch without either autopilot working is permitted.
On 9 January 2021, a Boeing 737-500 was climbing though 10,700 feet less than five minutes after departing Jakarta in daylight when it began to descend at an increasing rate from which no recovery occurred and 23 seconds later was destroyed by sea surface impact killing all 62 occupants. The Investigation concluded that the departure from controlled flight was unintentional and the result of the pilots’ inattention to their primary flight instruments when, during a turn with the autopilot engaged, an autothrottle malfunction created apparently unrecognised thrust asymmetry which culminated in a wing drop and a consequent loss of control.
On 20 July 2011, the flight crew of a Swiss European Avro RJ-100 on a positioning flight from Nuremburg to Zurich responded inappropriately to an unexpected ‘bank angle’ alert in IMC. Near loss of control followed during which a PAN was eventually declared. The situation was resolved by a belated actioning of the QRH checklist applicable to the failure symptoms experienced. The subsequent investigation attributed the event to inappropriate crew response to a failure of a single IRU and poor manual flying skill whilst the situation was resolved.
On 3 July 2017, an Airbus A319 sustained significant landing gear damage during the First Officer’s manual landing at Munich which recorded a vertical acceleration exceeding the threshold for a mandatory airworthiness inspection. That inspection found damage to nose and one main landing gear legs and, following Airbus advice, all three were replaced before release to service. The Investigation was unable to explain why neither pilot detected the incorrect pitch attitude and excessive rate of descent in time to take corrective action and noted that a reversion to manual flight during intermediate approach had been due to a technical malfunction.
On 25 May 2016, an Embraer ERJ 190 experienced a major electrical system failure soon after reaching its cruise altitude of FL 360. ATC were advised of problems and a descent to enable the APU to be started was made. This action restored most of the lost systems and the crew, not having declared an emergency, elected to complete their planned 400nm flight. The Investigation found that liquid contamination of an underfloor avionics bay had caused the electrical failure which had also involved fire and smoke without crew awareness because the smoke detection and air recirculation systems had been unpowered.
On 15 October 2015 a Boeing 747-300 experienced significant vibration from one of the engines almost immediately after take-off from Tehran Mehrabad. After the climb out was continued without reducing the affected engine thrust an uncontained failure followed 3 minutes later. The ejected debris caused the almost simultaneous failure of the No 4 engine, loss of multiple hydraulic systems and all the fuel from one wing tank. The Investigation attributed the vibration to the Operator's continued use of the engine without relevant Airworthiness Directive action and the subsequent failure to continued operation of the engine after its onset.
On 29 February 2016, control of a 50 kg, 3.8 metre wingspan UAV was lost during a flight test being conducted in a Temporary Segregated Area in northern Belgium. The UAV then climbed to 4,000 feet and took up a south south-westerly track across Belgium and into northern France where it crash-landed after the engine stopped. The Investigation found that control communications had been interrupted because of an incorrectly manufactured co-axial cable assembly and a separate autopilot software design flaw not previously identified. This then prevented the default recovery process from working. A loss of prescribed traffic separation was recorded.
On September 13 2008, at night and in good visual conditions*, a Boeing 737-500 operated by Aeroflot-Nord executed an unstabilised approach to Runway 21 at Bolshoye Savino Airport (Perm) which subsequently resulted in loss of control and terrain impact.
On 26 April 1994, the crew of an Airbus A300-600 lost control of their aircraft on final approach to Nagoya and the aircraft crashed within the airport perimeter. The Investigation found that an inadvertent mode selection error had triggered control difficulties which had been ultimately founded on an apparent lack understanding by both pilots of the full nature of the interaction between the systems controlling thrust and pitch on the aircraft type which were not typical of most other contemporary types. It was also concluded that the Captain's delay in taking control from the First Officer had exacerbated the situation.
On 22 October 2005, a British Airways Airbus A319 climbing en route to destination over south east England at night in VMC experienced a major but temporary electrical failure. Most services were re-instated within a short time and the flight was continued. However, during the subsequent Investigation, which took over two years, a series of significant deficiencies were identified in the design of the A320 series electrical system and the manufacturer-recommended responses to failures in it and in response, Airbus developed solutions to most of them.
Communications
On 6 February 2019, an Airbus A330-200 Captain’s Audio Control Panel (ACP) malfunctioned and began to emit smoke and electrical fumes after coffee was spilt on it. Subsequently, the right side ACP also failed, becoming hot enough to begin melting its plastic. Given the consequent significant communications difficulties, a turnback to Shannon was with both pilots taking turns to go on oxygen. The Investigation found that flight deck drinks were routinely served in unlidded cups with the cup size in use incompatible with the available cup holders. Pending provision of suitably-sized cups, the operator decided to begin providing cup lids.
On 29 February 2016, control of a 50 kg, 3.8 metre wingspan UAV was lost during a flight test being conducted in a Temporary Segregated Area in northern Belgium. The UAV then climbed to 4,000 feet and took up a south south-westerly track across Belgium and into northern France where it crash-landed after the engine stopped. The Investigation found that control communications had been interrupted because of an incorrectly manufactured co-axial cable assembly and a separate autopilot software design flaw not previously identified. This then prevented the default recovery process from working. A loss of prescribed traffic separation was recorded.
On 22nd August 1985, a B737-200 being operated by British Airtours, a wholly-owned subsidiary of British Airways, suffered an uncontained engine failure, with consequent damage from ejected debris enabling the initiation of a fuel-fed fire which spread to the fuselage during the rejected take off and continued to be fuel-fed after the aircraft stopped, leading to rapid destruction of the aircraft before many of the occupants had evacuated.
On 15 September 2006, an Easyjet Airbus A319, despatched under MEL provision with one engine generator inoperative and the corresponding electrical power supplied by the Auxiliary Power Unit generator, suffered a further en route electrical failure which included power loss to all COM radio equipment which could not then be re-instated. The flight was completed as flight planned using the remaining flight instruments with the one remaining transponder selected to the standard emergency code. The incident began near Nantes, France.
On 15 January 2009, an Embraer 195-200 being operated by UK Regional Airline Flybe was passing overhead Edinburgh UK at FL370 at night when communications problems between the flight deck and cabin crew occurred following the selection of emergency power as a precautionary measure after smoke, considered to possibly be of electrical origin, had been observed in the galley. An en route diversion with an uneventful outcome was accomplished.
Electrical Power
On 19 November 2020, the police operator of a DJI Matrice M210 UA lost control of it over Poole when it drifted beyond Visual Line Of Sight (VLOS) and communication ceased. It was subsequently damaged when colliding with a house in autoland mode. The Investigation found that a partial power failure had followed battery disconnection with its consequences not adequately communicated to the pilot. It faulted both the applicable UA User Manual content and the absence of sufficient UA status and detected wind information to the pilot. A failure to properly define VLOS was identified but not considered directly causal.
On 31 January 2011, a Singapore Airlines Airbus A380-800 was in the cruise when there was sudden loud noise and signs of associated electrical smoke and potential burning in a toilet compartment with a corresponding ECAM smoke alert. After a fire extinguisher had been discharged into the apparent source, there were no further signs of fire or smoke. Subsequent investigation found signs of burning below the toilet floor and it was concluded that excessive current caused by a short circuit which had resulted from a degraded cable had been the likely cause, with over current protection limiting the damage caused by overheating.
On 29 July 2011 an oxygen-fed fire started in the flight deck of an Egypt Air Boeing 777-200 about to depart from Cairo with most passengers boarded. The fire rapidly took hold despite attempts at extinguishing it but all passengers were safely evacuated via the still-attached air bridge access to doors 1L and 2L. The flight deck and adjacent structure was severely damaged. The Investigation could not conclusively determine the cause of the fire but suspected that wiring damage attributable to inadequately secured cabling may have provided a source of ignition for an oxygen leak from the crew emergency supply
On 7 January 2013, a battery fire on a Japan Air Lines Boeing 787-8 began almost immediately after passengers and crew had left the aircraft after its arrival at Boston on a scheduled passenger flight from Tokyo Narita. The primary structure of the aircraft was undamaged. Investigation found that an internal short circuit within a cell of the APU lithium-ion battery had led to uncontained thermal runaway in the battery leading to the release of smoke and fire. The origin of the malfunction was attributed to system design deficiency and the failure of the type certification process to detect this.
On 12 October 2018, the crew of a Boeing 737-400 already released to service under MEL conditions with an inoperative No 1 engine generator encountered a loss of services from the No 2 electrical system en-route to East Midlands which created a situation not addressed by QRH procedures. The flight was completed and both the new and existing defects were subsequently rectified relatively easily. The Investigation concluded that the operator involved appeared to be prioritising operational requirements over aircraft serviceability issues and made a range of Safety Recommendations aimed at improving company safety culture and the effectiveness of regulatory oversight.
On 24 August 2016, an ATR 72-600 experienced a static inverter failure which resulted in smoke and fumes which were identifiably electrical. Oxygen masks were donned, a MAYDAY declared and after the appropriate procedures had been followed, the smoke / fumes ceased. The Investigation noted a long history of capacitor failures affecting this unit which continued to be addressed by successive non-mandatory upgrades including another after this event. However, it was also found that there was no guidance on the re-instatement of systems disabled during the initial response to such events, in particular the total loss of AC electrical power.
On 14 October 2017, a Boeing 777-300ER en route to Sydney declared a MAYDAY and diverted to Adelaide after the annunciation of a lower deck hold fire warning and the concurrent detection of a burning smell in the flight deck. The remainder of the flight was completed without further event and after landing a precautionary rapid disembarkation was performed. The Investigation found that the fire risk had been removed by the prescribed crew response to the warning and that the burning which had occurred had been caused by chafing of a wiring loom misrouted at build.
On 25 May 2016, an Embraer ERJ 190 experienced a major electrical system failure soon after reaching its cruise altitude of FL 360. ATC were advised of problems and a descent to enable the APU to be started was made. This action restored most of the lost systems and the crew, not having declared an emergency, elected to complete their planned 400nm flight. The Investigation found that liquid contamination of an underfloor avionics bay had caused the electrical failure which had also involved fire and smoke without crew awareness because the smoke detection and air recirculation systems had been unpowered.
On 13 March 2013, smoke and fumes were immediately evident when the cable of an external GPU was connected to an ERJ170 aircraft on arrival after flight with passengers still on board. A precautionary rapid disembarkation was conducted. The Investigation found that a short circuit had caused extensive heat damage to the internal part of the aircraft GPU receptacle and minor damage to the surrounding structure and that the short circuit had occurred due to metallic FOD lodged within the external connecting box of aircraft GPU receptacle.
On 5 June 2015, a DHC8-200 descending towards Bradley experienced an in-flight fire which originated at a windshield terminal block. Attempts to extinguish the fire were unsuccessful with the electrical power still selected to the circuit. However, the fire eventually stopped and only smoke remained. An emergency evacuation was carried out after landing. The Investigation was unable to establish the way in which the malfunction that caused the fire arose but noted the continuing occurrence of similar events on the aircraft type and five Safety Recommendations were made to Bombardier to address the continuing risk.
Equipment/Furnishings
On 29 September 2017, the crew of an Airbus A320 detected a smell of burning plastic and simultaneously observed black smoke entering the flight deck near the right side rudder pedals. Completion of appropriate response procedures reduced the smoke and a diversion to Athens with a MAYDAY declared was without further event. The origin of the smoke and fumes was traced to the failure of the static inverter which was part of a batch which had been previously notified as faulty but not identified as such by the aircraft operator’s maintenance organisation which has since modified its relevant procedures.
On 12 July 2013 an unoccupied and unpowered Boeing 787-8, remotely parked at London Heathrow after an arrival earlier the same day caught fire. An investigation found that the source of the fire was an uncontained thermal runaway in the lithium-metal battery within an Emergency Locator Transmitter (ELT). Fifteen Safety Recommendations, all but one to the FAA, were made as a result of the Investigation.
On 11 March 2018, an Airbus AS350 engine failed during a commercial sightseeing flight and autorotation was initiated. The pilot then noticed that the floor-mounted fuel cut-off had been operated by part of the tether system of one of the five passengers but there was insufficient time to restore power. On water contact, the automatic floatation system operated asymmetrically and the helicopter submerged before the occupants could evacuate. Only the pilot was able to release his harness and escape because the unapproved adapted passenger harnesses had no quick release mechanism. The Investigation found systemic inadequacy of the operator s safety management system.
On 2 November 2017, the flight crew of an Airbus A320 climbing out of Cork detected a “strong and persistent” burning smell and after declaring a MAYDAY returned to Cork where confusing instructions from the crew resulted in a combination of the intended precautionary rapid disembarkation and an emergency evacuation using escape slides. The Investigation highlighted the necessity of clear and unambiguous communications with passengers which distinguish these two options and in particular noted the limitations in currently mandated pre flight briefings for passengers seated at over wing emergency exits.
On 29 March 2015, an Airbus A320 crew mismanaged the descent during a night non-precision approach at Halifax and continued below MDA without the mandatory autopilot disconnection until, with inadequate visual reference, the aircraft impacted terrain and obstructions 225 metres short of the runway. The aircraft was destroyed but there were no fatalities. The Investigation found that the crew did not monitor their descent against the required vertical profile, as there was no SOP requiring them to do so, and did not recognise in time that a go around was appropriate.
On 28 August 2006, a Hawker 800 collided with a glider at 16,000 feet in Class 'E' airspace. The glider became uncontrollable and its pilot evacuated by parachute. The Hawker was structurally damaged and one engine stopped but it was recovered to a nearby airport. The Investigation noted that the collision had occurred in an area well known for glider activity in which transport aircraft frequently avoided glider collisions using ATC traffic information or by following TCAS RAs. The glider was being flown by a visitor to the area with its transponder intentionally switched off to conserve battery power.
On 7 January 2008, a Boeing 747-400 being operated by Qantas on a scheduled passenger flight from London Heathrow to Bangkok was descending through FL100 about 13.5 nm NNW of destination in day VMC when indications of progressive electrical systems failure began to be annunciated. As the aircraft neared the end of the radar downwind leg, only the AC4 bus bar was providing AC power and the aircraft main battery was indicating discharge. A manual approach to a normal landing was subsequently accomplished and the aircraft taxied to the designated gate where passenger disembarkation took place. None of the 365 occupants, who included two heavy crew members who were present in the flight deck throughout the incident, had sustained any injury and the aircraft was undamaged.
On 1 August 2008, an en-route Embraer 195 despatched with one air conditioning pack inoperative lost all air conditioning and pressurisation when the other pack’s Air Cycle Machine (ACM) failed, releasing smoke and fumes into the aircraft. A MAYDAY diversion was made to the Isle of Man without further event. The Investigation found that the ACM failed due to rotor seizure caused by turbine blade root fatigue, the same failure which had led the other air conditioning system to fail failure four days earlier. It was understood that a modified ACM turbine housing was being developed to address the problem.
On 22nd August 1985, a B737-200 being operated by British Airtours, a wholly-owned subsidiary of British Airways, suffered an uncontained engine failure, with consequent damage from ejected debris enabling the initiation of a fuel-fed fire which spread to the fuselage during the rejected take off and continued to be fuel-fed after the aircraft stopped, leading to rapid destruction of the aircraft before many of the occupants had evacuated.
On 14 January 2002, a Boeing 737-200, operated by Lion Air, attempted to complete a daylight take off from Pekanbaru, Indonesia without flaps set after a failure to complete the before take off checks. The rejected take off was not initiated promptly and the aircraft overran the runway. The take off configuration warning failed to sound because the associated circuit breaker was so worn that it had previously auto-tripped and this had not been noticed.
Fire Protection
On 31 January 2011, a Singapore Airlines Airbus A380-800 was in the cruise when there was sudden loud noise and signs of associated electrical smoke and potential burning in a toilet compartment with a corresponding ECAM smoke alert. After a fire extinguisher had been discharged into the apparent source, there were no further signs of fire or smoke. Subsequent investigation found signs of burning below the toilet floor and it was concluded that excessive current caused by a short circuit which had resulted from a degraded cable had been the likely cause, with over current protection limiting the damage caused by overheating.
On 28 July 2011, 50 minutes after take off from Incheon, the crew of an Asiana Boeing 747-400F declared an emergency advising a main deck fire and an intention to divert to Jeju. The effects of the rapidly escalating fire eventually made it impossible to retain control and the aircraft crashed into the sea. The Investigation concluded that the origin of the fire was two adjacent pallets towards the rear of the main deck which contained Dangerous Goods shipments including Lithium ion batteries and flammable substances and that the aircraft had broken apart in mid-air following the loss of control.
On 25 May 2016, an Embraer ERJ 190 experienced a major electrical system failure soon after reaching its cruise altitude of FL 360. ATC were advised of problems and a descent to enable the APU to be started was made. This action restored most of the lost systems and the crew, not having declared an emergency, elected to complete their planned 400nm flight. The Investigation found that liquid contamination of an underfloor avionics bay had caused the electrical failure which had also involved fire and smoke without crew awareness because the smoke detection and air recirculation systems had been unpowered.
On 9 May 2010, Boeing 737-800 being operated by Swedish operator Viking Airlines on a public transport charter flight from Sharm el Sheikh, Egypt to Manchester UK and which had earlier suffered a malfunction which affected the level of redundancy in the aircraft pressurisation system, experienced a failure of the single air conditioning pack in use when over southern Austria and an emergency descent and en route diversion to Vienna were made. There were no injuries to any of the 196 occupants.
On 4 November 2010, a Qantas Airbus A380 climbing out of Singapore experienced a sudden and uncontained failure of one of its Rolls Royce Trent 900 engines which caused considerable collateral damage to the airframe and some of the aircraft systems. A PAN was declared and after appropriate crew responses including aircraft controllability checks, the aircraft returned to Singapore. The root cause of the failure was found to have been an undetected component manufacturing fault. The complex situation which resulted from the failure in flight was found to have exceeded the currently anticipated secondary damage from such an event.
On 3 September 2010, a UPS Boeing 747-400 freighter flight crew became aware of a main deck cargo fire 22 minutes after take off from Dubai. An emergency was declared and an air turn back commenced but a rapid build up of smoke on the flight deck made it increasingly difficult to see on the flight deck and to control the aircraft. An unsuccessful attempt to land at Dubai was followed by complete loss of flight control authority due to fire damage and terrain impact followed. The fire was attributed to auto-ignition of undeclared Dangerous Goods originally loaded in Hong Kong.
On 11 December 2008 an EMB 145 being operated by Finnish Commuter Airlines on a scheduled passenger flight caught fire during the taxi in after a night landing after the APU failed to start and a major electrical power failure occurred simultaneously. The fire was not detected until after the aircraft arrived on stand when, with the passengers still on board, a member of the ground crew saw signs of fire at the back of the aircraft. The aircraft s own fire suppression system was successfully used to extinguish the fire, the passengers left the aircraft and there were no injuries and only minor damage to the aircraft.
On 22nd August 1985, a B737-200 being operated by British Airtours, a wholly-owned subsidiary of British Airways, suffered an uncontained engine failure, with consequent damage from ejected debris enabling the initiation of a fuel-fed fire which spread to the fuselage during the rejected take off and continued to be fuel-fed after the aircraft stopped, leading to rapid destruction of the aircraft before many of the occupants had evacuated.
On 19 August 1980, a Lockheed L1011 operated by Saudi Arabian Airlines took off from Riyadh, Saudi Arabia - seven minutes later an aural warning indicated a smoke in the aft cargo compartment. Despite the successful landing all 301 persons on board perished due toxic fumes inhalation and uncontrolled fire.
On 26 February 2007, a Boeing 777-222 operated by United Airlines, after pushback from the stand at London Heathrow Airport, experienced internal failure of an electrical component which subsequently led to under-floor fire. The aircraft returned to a stand where was attended by the Airfield Fire Service and the passengers were evacuated.
Flight Controls
On 7 June 2021 an Embraer ERJ170 had just commenced its descent towards destination when both primary and secondary pitch trim systems failed resulting in excessive nose-down pitch control forces and an inoperative autopilot. The flight was completed without further event with the Pilot Flying using both hands on the control yoke to control pitch attitude manually. During the landing roll the nosewhweel steering system also failed. The pitch trim failure was attributed to probable jamming of the trim actuator due to water, possibly condensation, freezing within it. The steering system fault was attributed to a completely unrelated sensor failure.
On 15 January 2021, the pilot of a DJI Inspire 2 UAV being operated on a contracted aerial work task under a conditional permit lost control of it and, after exiting the approved operating area, it collided with the window of a hotel guest room causing consequential minor injuries to the occupant. The Investigation found that the loss of control was attributable to “strong magnetic interference” almost immediately after takeoff which caused the compass to feed unreliable data to the Internal Management Unit which destabilised its accelerometer and led to the loss of directional control which resulted in the collision.
On 14 November 2019, a Bombardier DHC8-400 experienced roll control difficulties after takeoff. These were manageable but it was decided a precautionary diversion should be made and this was accomplished without any significant roll control difficulty. The Investigation found that the right wing aileron control cable had failed due to undetected wear and that an option to fit an upgraded cable had not been taken. It also found the aircraft had a history of an intermittently unresponsive right aileron and discovered that signal noise filters which smoothed recorded data for all three primary flight control channels compromised FDR data value.
On 4 July 2019, the operator of an Alauda Airspeeder UAV lost control of it and it climbed to 8000 feet into controlled airspace at a designated holding pattern for London Gatwick before falling at 5000 fpm and impacting the ground close to housing. The Investigation was unable to establish the cause of the loss of control but noted that the system to immediately terminate a flight in such circumstances had also failed, thereby compromising public safety. The approval for operation of the UAV was found to been poorly performed and lacking any assessment of the airworthiness of the UAS.
On 8 October 2019, a BAe Jetstream 32 departing Münster/Osnabrück couldn’t be rotated and after beginning rejected takeoff from well above V1, the aircraft departed the side of the runway passing close to another aircraft at high speed before regaining the runway for the remainder of its deceleration. The Investigation noted that the flight was the first supervised line training sector for the very inexperienced First Officer but attributed the whole event to the Training Captain’s poor performance which had, apart many from other matters, led indirectly to the inability to rotate and to the subsequent directional control problem.
On 19 April 2018, a Boeing 737-900 made a high speed rejected takeoff at Kathmandu in response to a configuration warning and overran the runway without serious consequences. The Investigation found that when a false Takeoff Configuration Warning caused by an out of adjustment switch had been annunciated just after V1, the Captain had decided to reject the takeoff because of concerns about the local terrain and locally adverse weather. It was noted that the aircraft operator did not provide criteria for rejecting takeoff up to or above the 80 knot crosscheck but that the Boeing reference QRH did so.
On 27 November 2017, an Embraer EMB 550 crew ignored a pre-takeoff indication of an inoperative airframe ice protection system despite taxiing out and taking off in icing conditions. The flight proceeded normally until approach to Paris Le Bourget when the Captain was unable to flare for touchdown at the normal speed and a 4g runway impact which caused a main gear leg to pierce the wing followed. The Investigation found that the crew had failed to follow relevant normal and abnormal operating procedures and did not understand how flight envelope protection worked or why it had activated on approach.
On 5 April 2019, a Boeing 737-500 crew declared an emergency shortly after departing Madrid Barajas after problems maintaining normal lateral, vertical or airspeed control of their aircraft in IMC. After two failed attempts at ILS approaches in unexceptional weather conditions, the flight was successfully landed at a nearby military airbase. The Investigation found that a malfunction which probably prevented use of the Captain’s autopilot found before departure was not documented until after the flight but could not find a technical explanation for inability to control the aircraft manually given that dispatch without either autopilot working is permitted.
On 19 August 2012, the crew of a Flybe Finland ATR 72-200 approaching Helsinki failed to respond appropriately to a fault which limited rudder travel and were then unable to maintain directional control after touchdown with a veer off the runway then following. It was concluded that as well as prioritising a continued approach over properly dealing with the annunciated caution, crew technical knowledge in respect of the fault encountered had been poor and related training inadequate. Deficiencies found in relevant aircraft manufacturer operating documentation were considered to have been a significant factor and Safety Recommendations were made accordingly.
On 23 December 2010 an aircraft climbing out of Moscow in night IMC experienced a sudden in-flight pitch upset in which the three unrestrained passengers were injured, one seriously, as a result of an inappropriate pilot response to an annunciation of autopilot stabiliser trim malfunction. Despite extensive inspection, no root cause of this malfunction, which had been transitory, could be found. Crew QRH guidance in respect of the fault experienced was found to be unhelpful and crew knowledge of pitch trim - which could have eliminated any pitch disturbance - was deficient.
Fuel
On 31 August 2019, all six occupants of an Airbus AS350 B3 being used for a sightseeing flight in northern Norway were killed after control was suddenly lost and the helicopter impacted the terrain below where the wreckage was immediately consumed by an intense fire. The Investigation found no airworthiness issues which could have led to the accident and concluded that the loss of control had probably been due to servo transparency, a known limitation of the helicopter type. However, it was concluded that it was the absence of a crash-resistant fuel system which had led to the fatalities.
On 27 July 2019, a fuel configuration advisory was annunciated on a Boeing 767-300 about to depart Auckland as a result of wing tank imbalance. Having established there was no evidence of a fuel leak, they planned to correct the imbalance in flight but then delayed this until it had exceeded the permitted limits. The fault was only verbally reported after flight and the aircraft continued to operate without centre tank use with maintenance remaining unaware of the fault for several days. The cause of imbalance was a fuel system fault subject to a crew response which was not followed.
On 9 May 2019, a Cessna 550 level at FL 350 experienced an unexplained left engine rundown to idle and the crew began descent and a diversion to Savannah. When the right engine also began to run down passing 8000 feet, an emergency was declared and the already-planned straight-in approach was successfully accomplished without any engine thrust. The ongoing Investigation has already established that the likely cause was fuel contamination resulting from the inadvertent mixing of a required fuel additive with an unapproved substance known to form deposits which impede fuel flow when they accumulate on critical fuel system components.
On 27 March 2016 an ATR 42-500 had just departed Esbjerg when the right engine flamed out. It was decided to complete the planned short flight to Billund but on the night IMC approach there, the remaining engine malfunctioned and lost power. The approach was completed and the aircraft evacuated after landing. The Investigation found the left engine failed due to fuel starvation resulting from a faulty fuel quantity indication probably present since recent heavy maintenance and that the right engine had emitted flames during multiple compressor stalls to which it was vulnerable due to in-service deterioration and hot section damage.
On 16 April 2014, a pre-flight concern about whether a Boeing 777-200ER about to depart Singapore had been overfuelled was resolved by a manual check but an en-route fuel system alert led to close monitoring of the fuel system. When a divergent discrepancy between the two independent fuel remaining sources became apparent, an uneventful precautionary air turnback was made and overfuelling subsequently confirmed. The Investigation found that a system fault had caused overfuelling and that the manual check carried out to confirm the actual fuel load had failed to detect it because it had been not been performed correctly.
On 15 October 2015 a Boeing 747-300 experienced significant vibration from one of the engines almost immediately after take-off from Tehran Mehrabad. After the climb out was continued without reducing the affected engine thrust an uncontained failure followed 3 minutes later. The ejected debris caused the almost simultaneous failure of the No 4 engine, loss of multiple hydraulic systems and all the fuel from one wing tank. The Investigation attributed the vibration to the Operator's continued use of the engine without relevant Airworthiness Directive action and the subsequent failure to continued operation of the engine after its onset.
On 28 August 2006, a Hawker 800 collided with a glider at 16,000 feet in Class 'E' airspace. The glider became uncontrollable and its pilot evacuated by parachute. The Hawker was structurally damaged and one engine stopped but it was recovered to a nearby airport. The Investigation noted that the collision had occurred in an area well known for glider activity in which transport aircraft frequently avoided glider collisions using ATC traffic information or by following TCAS RAs. The glider was being flown by a visitor to the area with its transponder intentionally switched off to conserve battery power.
On 12 December 2011, the crew of a Xian MA60 delayed their response to an engine fire warning until the existence of a fire had been confirmed by visual inspection and then failed to follow the memory engine shutdown drill properly so that fire continued for considerably longer than it should have. The Investigation found that an improperly tightened fuel line coupling which had been getting slowly but progressively worse during earlier flights had caused the fire. It was also concluded that the pilots' delay in responding to the fire had prolonged risk exposure and jeopardised the safety of the flight.
On 22 August 2015 the pilot of a civil-operated Hawker Hunter carrying out a flying display sequence at Shoreham failed to complete a loop and partial roll manoeuvre and the aircraft crashed into road traffic unrelated to the airshow and exploded causing multiple third party fatalities and injuries. The Investigation found that the pilot had failed to enter the manoeuvre correctly and then failed to abandon it when it should have been evident that it could not be completed. It was concluded that the wider context for the accident was inadequate regulatory oversight of UK civil air display flying risk management.
On 4 November 2010, a Qantas Airbus A380 climbing out of Singapore experienced a sudden and uncontained failure of one of its Rolls Royce Trent 900 engines which caused considerable collateral damage to the airframe and some of the aircraft systems. A PAN was declared and after appropriate crew responses including aircraft controllability checks, the aircraft returned to Singapore. The root cause of the failure was found to have been an undetected component manufacturing fault. The complex situation which resulted from the failure in flight was found to have exceeded the currently anticipated secondary damage from such an event.
Hydraulic Power
On 15 December 2019, an Airbus A330-200 turned back to Sydney shortly after departure when a major hydraulic system leak was annunciated. The return was uneventful until engine shutdown after clearing the runway following which APU use for air conditioning was followed by a gradual build up of hydraulic haze and fumes which eventually prompted an emergency evacuation. The Investigation found that fluid leaking from ruptured rudder servo hose had entered the APU air intake. The resulting evacuation was found to have been somewhat disorganised with this being attributed mainly to a combination of inadequate cabin crew procedures and training.
On 23 July 2011, a Boeing 737-300 being operated by Jet2.com on a passenger flight from Leeds/Bradford to Paris CDG experienced violent vibration from the main landing gear at touch down in normal day visibility on runway 27R at a normal speed off a stabilised approach. This vibration was accompanied by lateral acceleration that made directional control difficult but the aircraft was kept on the runway and at a speed of 75 knots, the vibrations abruptly stopped. Once clear of the runway, the aircraft was stopped and the engines shutdown prior to a tow to the gate. None of the 133 occupants were injured.
On 15 October 2015 a Boeing 747-300 experienced significant vibration from one of the engines almost immediately after take-off from Tehran Mehrabad. After the climb out was continued without reducing the affected engine thrust an uncontained failure followed 3 minutes later. The ejected debris caused the almost simultaneous failure of the No 4 engine, loss of multiple hydraulic systems and all the fuel from one wing tank. The Investigation attributed the vibration to the Operator's continued use of the engine without relevant Airworthiness Directive action and the subsequent failure to continued operation of the engine after its onset.
On 1 November 2011, a Boeing 767-300 landed at Warsaw with its landing gear retracted after declaring an emergency in anticipation of the possible consequences which in this event included an engine fire and a full but successful emergency evacuation. The Investigation attributed inability to achieve successful gear extension using either alternate system or free fall to crew failure to notice that the Battery Busbar CB which controlled power to the uplock release mechanism was tripped. Gear extension using the normal system had been precluded in advance by a partial hydraulic system failure soon after takeoff from New York.
An announcement by the Captain of a fully-boarded Boeing 757-200 about to depart which was intended to initiate a Precautionary Rapid Disembarkation due to smoke from a hydraulic leak was confusing and a partial emergency evacuation followed. The Investigation found that Cabin Crew only knew of this via the announcement and noted subsequent replacement of the applicable procedures by an improved version, although this was still considered to lack resilience in one respect. The event was considered to have illustrated the importance of having cabin crew close to doors when passengers are on board aircraft on the ground.
On 4 October 2014, the fracture of a hydraulic hose during an A330-200 pushback at night at Karachi was followed by dense fumes in the form of hydraulic fluid mist filling the aircraft cabin and flight deck. After some delay, during which a delay in isolating the APU air bleed exacerbated the ingress of fumes, the aircraft was towed back onto stand and an emergency evacuation completed. During the return to stand, a PBE unit malfunctioned and caught fire when one of the cabin crew attempted to use it which prevented use of the exit adjacent to it for evacuation.
On 26 February 2013, the crew of a Boeing 752 temporarily lost full control of their aircraft on a night auto-ILS approach at Keflavik when an un-commanded roll occurred during flap deployment after an earlier partial loss of normal hydraulic system pressure. The origin of the upset was found to have been a latent fatigue failure of a roll spoiler component, the effect of which had only become significant in the absence of normal hydraulic pressure and had been initially masked by autopilot authority until this was exceeded during flap deployment.
On 17 January 2007, a Bombardier CRJ 100 being operated by French airline Brit Air on a scheduled night passenger flight from Paris CDG to Southampton could not be directionally controlled after touchdown on a dry surface in normal visibility and almost calm winds and departed the side of the runway during the landing roll. There were no injuries to any of the 36 occupants and there was no damage to the aircraft.
On 22 June 2009, an Airbus A340-300 being operated by Finnair suffered a single tyre failure during take off on a scheduled passenger flight to Helsinki and malfunction assessed as consequential by the flight crew occurred to the hydraulic system. The flight proceeded to destination and carried out a daylight landing there in normal visibility without any further aircraft damage. Because of a further deterioration in the status of the aircraft hydraulic systems during the landing roll, the aircraft was stopped on the runway and then towed into the gate. No persons were injured in this incident.
On August 12, 1985 a Boeing 747 SR-100 operated by Japan Air Lines experienced a loss of control attributed to loss of the vertical stabiliser. After the declaration of the emergency, the aircraft continued its flight for 30 minutes and subsequently impacted terrain in a mountainous area in Gunma Prefecture, Japan.
Ice and Rain Protection
On 7 August 2020, a Boeing 737-800 making its second attempt to land at Calicut off a night ILS approach with a significant tailwind component became unstabilised and touched down approximately half way down the 2,700 metre-long wet table top runway and departed the end of it at 85 knots before continuing through the RESA and a fence and then dropping sharply onto a road. This caused the fuselage to separate into three pieces with 97 of the 190 occupants including both pilots being fatally or seriously injured and 34 others sustaining minor injuries. Significant fuel spillage occurred but there was no fire.
On 27 November 2017, an Embraer EMB 550 crew ignored a pre-takeoff indication of an inoperative airframe ice protection system despite taxiing out and taking off in icing conditions. The flight proceeded normally until approach to Paris Le Bourget when the Captain was unable to flare for touchdown at the normal speed and a 4g runway impact which caused a main gear leg to pierce the wing followed. The Investigation found that the crew had failed to follow relevant normal and abnormal operating procedures and did not understand how flight envelope protection worked or why it had activated on approach.
On 25 February 2017, an Airbus A320 left the side of the landing runway at Toronto when, for undetermined reasons, the Captain, as Pilot Flying, set up a drift to the right just before touchdown. This was then followed by a lateral runway excursion into wet grass in rain-reduced visibility which continued for 1,650 metres before the aircraft regained the runway and stopped. The Investigation noted that both the absence of runway centreline lighting and the aircraft operator’s policy of not activating the aircraft rain repellent system or applying the alternative hydrophobic windshield coating may have increased the excursion risk.
On 13 June 2013, a rushed and unstable visual approach to Marsh Harbour by a Saab 340B was followed by a mishandled landing and a runway excursion. The Investigation concluded that the way the aircraft had been operated had been contrary to expectations in almost every respect. This had set the scene for the continuation of a visual approach to an attempted landing in circumstances where there had been multiple indications that there was no option but to break off the approach, including a total loss of forward visibility in very heavy rain as the runway neared.
On 4 June 2002, the crew of an MD82 in the cruise at FL330 with AP and A/T engaged failed to notice progressive loss of airspeed and concurrent increase in pitch attitude as both engines rolled back to thrust levels which could not sustain level flight. The aircraft stalled and a recovery was accomplished with significant altitude necessary before engine thrust was restored and a diversion made. The Investigation attributed the engine rollback to ice crystal icing obstructing the engine inlet pressure sensors following crew failure to use the engine anti-icing as prescribed. Two Safety Recommendations were made.
On 5 November 2014, the crew of an Airbus A321 temporarily lost control of their aircraft in the cruise and were unable to regain it until 4000 feet of altitude had been lost. An investigation into the causes is continuing but it is already known that blockage of more than one AOA probe resulted in unwanted activation of high AOA protection which could not be stopped by normal sidestick inputs until two of the three ADRs had been intentionally deactivated in order to put the flight control system into Alternate Law.
On 11 January 2010, a British Aerospace ATP crew attempting to take off from Helsinki after a two-step airframe de/anti icing treatment (Type 2 and Type 4 fluids) were unable to rotate and the take off was successfully rejected from above V1. The Investigation found that thickened de/anti ice fluid residues had frozen in the gap between the leading edge of the elevator and the horizontal stabiliser and that there had been many other similarly-caused occurrences to aircraft without powered flying controls. There was concern that use of such thickened de/anti ice fluids was not directly covered by safety regulation.
On 1 June 2009, an Airbus A330-200 being operated by Air France on a scheduled passenger flight from Rio de Janeiro to Paris CDG as AF447 exited controlled flight and crashed into the sea with the loss of the aircraft and all 228 occupants. It was found that the loss of control followed an inappropriate response by the flight crew to a transient loss of airspeed indications in the cruise which resulted from the vulnerability of the pitot heads to ice crystal icing.
On 5 January 2004, a Fokker 70, operated by Austrian Airlines, carried out a forced landing in a field 2.5 nm short of Munich Runway 26L following loss of thrust from both engines due to icing.
On 21 November 2006, an Air Canada Jazz CL-600-2B19 on a scheduled flight from Vancouver to Prince George was cleared for a non-precision approach at destination. During a missed approach because of worse than forecast weather conditions, the crew were unable to retract the flaps from their 45 degree landing setting. A diversion to the designated alternate was commenced but en route, ATC were requested to provide radar vectors to Fort St. John and an emergency was declared due to a low fuel prediction on arrival. The aircraft subsequently landed without further problem at Fort St. John with about 500 pounds of fuel remaining, equivalent to less than 10 minutes of flight time.
Indicating / Recording Systems
On 22 September 2021, a Boeing 787-9 was found on arrival at its destination, Los Angeles, to have completed the 14½ hour flight from Melbourne with all four fan cowl static ports taped over. The crew had not observed any adverse consequence. The Investigation attributed the oversight to inadequate pre-flight maintenance and operational procedures and found that failure to identify the taping had resulted in the aircraft departing with reduced redundancy to the engine electronic control systems of both engines.
On 6 February 1996, a Boeing 757-200 took off from Puerto Plata at night despite awareness at the 80 knot check that the Captains altimeter was not working. Thereafter, the crew became confused as to their actual airspeed and lost control before the aircraft hit the sea surface less than five minutes after takeoff. The Investigation found that the Captain’s pitot probe was blocked and that the three pilots on the flight deck had become confused about which airspeed indications were reliable and had then not recovered from an aerodynamic stall which followed the wholly avoidable mismanagement of the aircraft flight path.
On 9 June 2021, an Airbus A320 Captain performing a relatively light weight and therefore rapid-acceleration takeoff from London Heathrow recognised as the standard 100 knot call was imminent that he had no speed indication so announced and performed a high speed rejected takeoff. Subsequent maintenance inspection found that the left pitot mast was blocked by the nest of a seasonally active solitary flying insect, noting that the aircraft had previously been parked for 24 hours on a non-terminal stand. Similar events, including another rejected takeoff, then followed and a comprehensive combined Investigation found all were of similar origin.
On 7 February 2018, a Boeing 737-800 experienced an airspeed mismatch during takeoff on a post maintenance positioning flight but having identified the faulty system by reference to the standby instrumentation, the intended flight was completed without further event. After the recorded defect was then signed off as “no fault found” after a failure to follow the applicable fault-finding procedure, the same happened on the next (revenue) flight but with an air turnback made. The Investigation found that the faulty sensor had been fitted at build three earlier with a contaminated component which had slowly caused sensor malfunction to develop.
On 4 October 2013, a Boeing 747-200 touched down short of the intended landing runway at Sokoto after the Captain opted to reduce track miles by making a direct visual contact approach in dark night calm wind conditions rather than continuing as initially cleared towards an ILS approach in the reciprocal runway direction. The Investigation was hampered by an inoperative FDR and failure to preserve relevant CVR data on the grounded aircraft and concluded that the decision to make a visual approach rather than an ILS approach when the VASI was out of service for both runways was inappropriate.
On 11 March 2018 an Unreliable Speed Alert occurred on a Bombardier Challenger, the Captain’s airspeed increasing whilst the First Officer’s decreased. The First Officer attempted to commence the corresponding drill but the Captain’s interruptions prevented this and a (false) overspeed warning followed. The Captain’s response to both alerts was to reduce thrust which led to a Stall Warning followed, after no response, by stick pusher activation which was repeatedly opposed by the Captain despite calls to stop from the First Officer. The stalled condition continued for almost five minutes until a 30,000 feet descent was terminated by terrain impact.
On 1 December 2017, an Airbus A320 made an unintentional - and unrecognised - hard landing at Pristina. As the automated system for alerting outside-limits hard landings was only partially configured and output from the sole available channel was not available, the aircraft continued in service for a further eight sectors before an exceedance was confirmed and the aircraft grounded. The Investigation noted that whilst the aircraft Captain is responsible for recording potential hard landings, the aircraft operator involved should ensure that at least one of the available automated alerting channels is always functional in support of crew subjective judgement.
On 12 March 2014, an Airbus A319 left engine stopped without any apparent cause on approach to Paris CDG. The crew then started the APU which also stopped. The Investigation found that the cause was engine and APU fuel starvation caused by non-identification of a recurring intermittent malfunction in the fuel quantity indicating system because of a combination of factors including crew failure to record fuel status in line with clear instructions and an inadequate maintenance troubleshooting manual. An inadequately-written abnormal crew drill and the crew’s inadequate fuel system knowledge then resulted in the fuel crossfeed valve not being opened.
On 5 April 2019, a Boeing 737-500 crew declared an emergency shortly after departing Madrid Barajas after problems maintaining normal lateral, vertical or airspeed control of their aircraft in IMC. After two failed attempts at ILS approaches in unexceptional weather conditions, the flight was successfully landed at a nearby military airbase. The Investigation found that a malfunction which probably prevented use of the Captain’s autopilot found before departure was not documented until after the flight but could not find a technical explanation for inability to control the aircraft manually given that dispatch without either autopilot working is permitted.
On 16 April 2012, a Virgin Atlantic A330-300 made an air turnback to London Gatwick after repetitive hold smoke detector warnings began to occur during the climb. Continuing uncertainty about whether the warnings, which continued after landing, were false led to the decision to order an emergency evacuation on the runway. Subsequent investigation found that the smoke warnings had all been false and had mainly come from one faulty detector. It also found that aspects of the way the evacuation had taken place had indicated where there were opportunities to try and improve passenger behaviour.
Landing Gear
On 3 December 2021, a Boeing 737MAX-8 released to service with antiskid and autobrake systems inoperative in accordance with Minimum Equipment List procedures then operated two sectors. On the return to Singapore, both left main landing gear tyres were sufficiently damaged during landing to cause the bursting of one and deflation of the other. The cause of this was failure to deploy the speedbrakes manually as required. A similar error on the previous sector did not have the same outcome because the relatively more positive touchdown enabled automatic speedbrake deployment and wheel spin was accompanied by simultaneous manual braking.
On 7 June 2021 an Embraer ERJ170 had just commenced its descent towards destination when both primary and secondary pitch trim systems failed resulting in excessive nose-down pitch control forces and an inoperative autopilot. The flight was completed without further event with the Pilot Flying using both hands on the control yoke to control pitch attitude manually. During the landing roll the nosewhweel steering system also failed. The pitch trim failure was attributed to probable jamming of the trim actuator due to water, possibly condensation, freezing within it. The steering system fault was attributed to a completely unrelated sensor failure.
On 6 August 2021, an Airbus A319 experienced uncommanded loss of both Flight Directors and the Flight Mode Annunciator and disconnection of both autopilot and autothrust in the climb. After levelling at FL350, significant inertial reference position inconsistencies were observed. A precautionary PAN was declared and the flight was completed. Investigation found that the cause was a momentary abnormal vertical shock load transferred to Inertial Reference System equipment through an overextended nose gear shock absorber by a sharp jolt during takeoff caused by a runway patch repair. Sensitivity of the particular inertial reference system installed on the aircraft was noted.
On 1 August 2019, an Airbus A320 annunciated an abnormal gear status indication when retraction was attempted after takeoff. Soon afterwards, an aircraft part was observed by an aircraft following the same taxi route as the A320 and recovered. After completing relevant drills, the A320 returned and completed a landing with significant damage to the left main gear which was nevertheless locked down. The runway was vacated and passengers disembarked. The Investigation found that the cause of the problem was the cyclic fatigue of a pin linking the two parts of the left main gear torque link of manufacturing origin.
On 25 March 2018, an ATR 42-500 main landing gear bay door weighing 15 kg detached shortly after a night descent had begun but this was unknown until the flight arrived at Aurillac. The Investigation found that the root cause of the detachment was a loose securing nut which had triggered a sequence of secondary failures within a single flight which culminated in the release of the door. It was concluded that the event highlighted specific and systemic weakness in relevant airworthiness documentation and practice in relation to the lost door and the use of fasteners on this aircraft type generally.
On 11 December 2019, a Bombardier BD700 Global 6000 making a night landing at Liverpool suffered a nose wheel steering failure shortly after touchdown. The crew were unable to prevent the aircraft departing the side of the runway into a grassed area where it stopped, undamaged, in mud. The Investigation found that the crew response was contrary to that needed for continued directional control but also that no pilot training or QRH procedure covered such a failure occurring at high speed nor was adequate guidance available on mitigating the risk of inadvertent opposite brake application during significant rudder deflection.
On 15 November 2018, a Bombardier DHC8-300 made a main gear only touchdown at Stephenville with only minor damage after diverting there when the nose landing gear only partially extended when routinely selected on approach at the originally intended destination. The Investigation found that the cause was incorrect nose gear assembly which had allowed hydraulic fluid to leak and eventually led to it jamming. There was some concern at the way the flight was conducted following the problem which involved continuous smartphone communications with the operator and an overspeed which it was considered constituted an avoidable risk to safety.
On 13 April 2013, an Air France Airbus A330-200 was damaged during a hard (2.74 G) landing at Caracas after the aircraft commander continued despite the aircraft becoming unstabilised below 500 feet agl with an EGPWS ‘SINK RATE’ activation beginning in the flare. Following a superficial inspection, maintenance personnel determined that no action was required and released the aircraft to service. After take off, it was impossible to retract the landing gear and the aircraft returned. Considerable damage from the earlier landing was then found to both fuselage and landing gear which had rendered the aircraft unfit to fly.
On 16 November 2012, an Air Contractors Airbus A300 departed the left the side of the landing runway at Bratislava after an abnormal response to directional control inputs. Investigation found that incorrect and undetected re-assembly of the nose gear torque links had led to the excursion and that absence of clear instructions in maintenance manuals, since rectified, had facilitated this. It was also considered that the absence of any regulation requiring equipment in the vicinity of the runway to be designed to minimise potential damage to aircraft departing the paved surface had contributed to the damage caused by the accident.
On 16 July 2012, the left main landing gear of a Blue Islands ATR 42-300 collapsed during landing at Jersey. The aircraft stopped quickly on the runway as the left wing and propeller made ground contact. Although the crew saw no imminent danger once the aircraft had stopped, the passengers thought otherwise and perceived the need for an emergency evacuation which the sole cabin crew facilitated. The Investigation found that the fatigue failure of a side brace had initiated the gear collapse and that the origin of this was a casting discontinuity in a billet of aluminium produced to specification.
Navigation
On 6 August 2021, an Airbus A319 experienced uncommanded loss of both Flight Directors and the Flight Mode Annunciator and disconnection of both autopilot and autothrust in the climb. After levelling at FL350, significant inertial reference position inconsistencies were observed. A precautionary PAN was declared and the flight was completed. Investigation found that the cause was a momentary abnormal vertical shock load transferred to Inertial Reference System equipment through an overextended nose gear shock absorber by a sharp jolt during takeoff caused by a runway patch repair. Sensitivity of the particular inertial reference system installed on the aircraft was noted.
On 15 January 2021, the pilot of a DJI Inspire 2 UAV being operated on a contracted aerial work task under a conditional permit lost control of it and, after exiting the approved operating area, it collided with the window of a hotel guest room causing consequential minor injuries to the occupant. The Investigation found that the loss of control was attributable to “strong magnetic interference” almost immediately after takeoff which caused the compass to feed unreliable data to the Internal Management Unit which destabilised its accelerometer and led to the loss of directional control which resulted in the collision.
On 12 July 2013 an unoccupied and unpowered Boeing 787-8, remotely parked at London Heathrow after an arrival earlier the same day caught fire. An investigation found that the source of the fire was an uncontained thermal runaway in the lithium-metal battery within an Emergency Locator Transmitter (ELT). Fifteen Safety Recommendations, all but one to the FAA, were made as a result of the Investigation.
On 27 June 2016, an Airbus A319 narrowly avoided a mid-air collision with an AS532 Cougar helicopter whose single transponder had failed earlier whilst conducting a local pre-delivery test flight whilst both were positioning visually as cleared to land at Marseille and after the helicopter had also temporarily disappeared from primary radar. Neither aircraft crew had detected the other prior to their tracks crossing at a similar altitude. The Investigation attributed the conflict to an inappropriate ATC response to the temporary loss of radar contact with the helicopter aggravated by inaccurate position reports and non-compliance with the aerodrome circuit altitude by the helicopter crew.
On 25 May 2016, an Embraer ERJ 190 experienced a major electrical system failure soon after reaching its cruise altitude of FL 360. ATC were advised of problems and a descent to enable the APU to be started was made. This action restored most of the lost systems and the crew, not having declared an emergency, elected to complete their planned 400nm flight. The Investigation found that liquid contamination of an underfloor avionics bay had caused the electrical failure which had also involved fire and smoke without crew awareness because the smoke detection and air recirculation systems had been unpowered.
On 3 March 2014, a Dassault Falcon 20 engaged in navigation aid calibration for the Regulator was flown into the sea near Kish Island in dark night conditions. The Investigation concluded that the available evidence indicated that the aircraft had been inadvertently flown into the sea as the consequence of the crew experiencing somatogravic illusion. It was also noted that the absence of a functioning radio altimeter and pilot fatigue attributable to the long duty period was likely to have exacerbated the pilots' vulnerability to this illusion.
On 18 June 2016, a PC12 crew experienced a sudden corruption of the SVS image on their PFDs soon after a night take-off and the Pilot Flying initially reacted by increasing pitch in response to the false image which had obscured the primary flight path symbology on the PFD. Recovery was achieved before the resulting airspeed drop had activated the Stall Protection System by the pilots transferring their attention to the Standby Instrument Display. The Investigation noted that the SVS was not certified for primary flight path control but that the failure had created temporary spatial disorientation.
On 28 August 2006, a Hawker 800 collided with a glider at 16,000 feet in Class 'E' airspace. The glider became uncontrollable and its pilot evacuated by parachute. The Hawker was structurally damaged and one engine stopped but it was recovered to a nearby airport. The Investigation noted that the collision had occurred in an area well known for glider activity in which transport aircraft frequently avoided glider collisions using ATC traffic information or by following TCAS RAs. The glider was being flown by a visitor to the area with its transponder intentionally switched off to conserve battery power.
On 11 January 2007, an Air New Zealand Airbus A320 which had just departed Sydney Australia for Auckland, New Zealand was observed to have turned onto a heading contrary to the ATC-issued radar heading. When so advised by ATC, the crew checked the aircraft compasses and found that they were reading approximately 40 degrees off the correct heading.
On 7 October 2008, an Airbus A330-300 aircraft experienced multiple system failure indications followed by uncommanded pitch-down events which resulted in serious injuries to passengers and cabin crew.
Oxygen
On 29 July 2011 an oxygen-fed fire started in the flight deck of an Egypt Air Boeing 777-200 about to depart from Cairo with most passengers boarded. The fire rapidly took hold despite attempts at extinguishing it but all passengers were safely evacuated via the still-attached air bridge access to doors 1L and 2L. The flight deck and adjacent structure was severely damaged. The Investigation could not conclusively determine the cause of the fire but suspected that wiring damage attributable to inadequately secured cabling may have provided a source of ignition for an oxygen leak from the crew emergency supply
On 24 August 2001, an Air Transat Airbus A330-200 eastbound across the North Atlantic at night experienced a double-engine flameout after which Lajes on Terceira Island in the Azores was identified as the best diversion and a successful glide approach and landing there was subsequently achieved. The Investigation found that the flameouts had been the result of fuel exhaustion after a fuel leak from the right engine caused by a pre flight maintenance error. Fuel exhaustion was found to have occurred because the flight crew did not perform the QRH procedure applicable to an in-flight fuel leak.
On 22 March 2007, climbing out of Stockholm Sweden, the crew of a Malmö Aviation Avro RJ100 failed to notice that the aircraft was not pressurised until cabin crew advised them of automatic cabin oxygen mask deployment.
On 25 July 2008, a Boeing 747 suffered a rapid depressurisation of the cabin following the sudden failure of an oxygen cylinder, which had ruptured the aircraft's pressure hull. The incident occurred 475 km north-west of Manila, Philippines.
Airborne Auxiliary Power (APU)
On 15 December 2019, an Airbus A330-200 turned back to Sydney shortly after departure when a major hydraulic system leak was annunciated. The return was uneventful until engine shutdown after clearing the runway following which APU use for air conditioning was followed by a gradual build up of hydraulic haze and fumes which eventually prompted an emergency evacuation. The Investigation found that fluid leaking from ruptured rudder servo hose had entered the APU air intake. The resulting evacuation was found to have been somewhat disorganised with this being attributed mainly to a combination of inadequate cabin crew procedures and training.
On 20 January 2015, The APU of a Fokker 100 being routinely de-iced prior to departing Nuremburg oversped as a result of the ignition of ingested de-icing fluid in the APU. This led to its explosive uncontained failure as the result of which ejected debris entered the aft cabin and smoke occurred. No occupants were injured and all were promptly disembarked. The Investigation found that the de-icing contractor involved had not followed manufacturer-issued aircraft-specific de-icing procedures and in the continued absence of any applicable safety regulatory oversight of ground de-icing activity, corresponding Safety Recommendations were made.
On 26 June 2016, thick white smoke suddenly appeared in the cabin of a fully loaded Airbus A330-300 prior to engine start with the door used for boarding still connected to the air bridge. An emergency evacuation initiated by cabin crew was accomplished without injury although amidst some confusion due to a brief conflict between flight crew and cabin crew instructions. The Investigation found that the smoke had been caused when an APU seal failed and hot oil entered the bleed air supply and pyrolysed. Safety Recommendations in respect of both crew communication and procedures and APU auto-shutdown were made.
On 25 September 2001, an Embraer 145 in descent to Manchester sustained a low power lightning strike which was followed, within a few seconds, by the left engine stopping without failure annunciation. A successful single engine landing followed. The Investigation concluded that the cause of failure of the FADEC-controlled AE3007 engine (which has no surge recovery logic) was the aero-thermal effects of the strike to which all aircraft with relatively small diameter fuselages and close mounted engines are vulnerable. It was considered that there was a risk of simultaneous double engine flameout in such circumstances which was impossible to quantify.
On 28 July 2013, with passengers still boarding an Air France Boeing 777-300, an abnormal 'burnt' smell was detected by the crew and then thin smoke appeared in the cabin. A MAYDAY was declared and the Captain made a PA telling the cabin crew to evacuate the passengers via the doors, only via the doors. The resulting evacuation process was confused but eventually completed. The Investigation attributed the confused evacuation to the way it had been ordered and established that a fault in the APU had caused the smoke and fumes which had the potential to be toxic.
On 11 December 2008 an EMB 145 being operated by Finnish Commuter Airlines on a scheduled passenger flight caught fire during the taxi in after a night landing after the APU failed to start and a major electrical power failure occurred simultaneously. The fire was not detected until after the aircraft arrived on stand when, with the passengers still on board, a member of the ground crew saw signs of fire at the back of the aircraft. The aircraft s own fire suppression system was successfully used to extinguish the fire, the passengers left the aircraft and there were no injuries and only minor damage to the aircraft.
Propellers
On 7 December 2016, the crew of an ATR 42-500 lost control after airworthiness-related complications followed shutdown of the left engine whilst in the cruise and high speed terrain impact followed. The Investigation concluded that three pre-existing faults with the left engine and its propeller control mechanism had led to a loss of power which had necessitated its shutdown but that these faults had then caused much higher left side drag than would normally result from an engine shutdown and made it progressively more difficult to maintain control. Recovery from a first loss of control was followed by another without recovery.
On 17 March 2017, uncommanded engine indications on a Saab 340B en route to Sydney were followed by vibration of the right engine after which, as the crew commenced right engine shutdown, its propeller assembly separated from the engine. A PAN was declared and the flight subsequently reached Sydney without further event. The Investigation found that the propeller gearbox shaft had fractured because of undetected internal fatigue cracking in the shaft. Applicable in-service shaft inspection procedures were found to be inadequate and mandatory enhancements to these procedures have since been introduced.
On 28 November 2013, a Saab 2000 departing Lugano suffered an engine failure for no apparent reason and the crew determined that diversion to Milan was preferable to return to Lugano or continued climb over high terrain to reach intended destination Zurich. The Investigation found that the loss of engine power experienced was due to a double FADEC failure with a transient malfunction of one channel resulting in an automated transfer to the other channel which already had an undetected permanent fault attributable to maintenance error. It was noted that the airline involved had contracted out all continuing airworthiness responsibilities.
On 9 January 2015, a Saab 340B encountered a flock of medium-sized birds soon after decelerating through 80 knots during its landing roll at Moruya. A subsequent flight crew inspection in accordance with the prevailing operator procedures concluded that the aircraft could continue in service but after completion of the next flight, a propeller blade tip was found to be missing. The Investigation concluded that the blade failure was a result of the earlier bird impact and found that airline procedures allowing pilots to determine continued airworthiness after a significant birdstrike had unknowingly been invalid.
On 30 November 2014, an ATR 72-500 suddenly experienced severe propeller vibrations whilst descending through approximately 7,000 feet with the power levers at flight idle. The vibrations subsided after the crew feathered the right engine propeller and then shut the right engine down. The flight was completed without further event. Severe damage to the right propeller mechanism was found with significant consequential damage to the engine. Several other similar events were found to have occurred to other ATR72 aircraft and, since the Investigation could not determine the cause, the EASA was recommended to impose temporary operating limitations pending OEM resolution.
On 19 August 2013, a fire occurred in the right engine of a Douglas DC3-C on take off from Yellowknife. After engine shutdown, a right hand circuit was made in an attempt to land back on another runway but trees were struck and the aircraft crash-landed south of it. Emergency evacuation was successful. The Investigation found that a pre-existing cylinder fatigue crack had caused the engine failure/fire and that the propeller feathering pump had malfunctioned. It was found that an overweight take off had occurred and that various unsafe practices had persisted despite the regulatory approval of the Operator's SMS.
On 13 October 2011, the Captain of a Bombardier DHC8-100 manually flying a low power, steep descent in an attempt to get below cloud to be able to see the destination aerodrome inadvertently allowed the speed to increase sufficiently to trigger an overspeed warning. In response, the power levers were rapidly retarded and both propellers entered the ground range and oversped. As a result, one engine was damaged beyond use and the other could not be unfeathered. A forced landing was made following which the aircraft caught fire. All three crew members but only one of the 29 passengers survived.
On 14 January 2013, selection of the power levers to ground idle after an ATR 72-200 touchdown at Copenhagen produced only one of the two expected low pitch indications. As the First Officer called 'one low pitch' in accordance with SOP, the Captain selected both engines into reverse. He was unable to prevent the resultant veer off the runway. After travelling approximately 350 metres on grass alongside the runway as groundspeed reduced, the runway was regained. A propeller control fault which would have prevented low pitch transition on the right engine was recorded but could not subsequently be replicated.
On 11 August 1991, an British Aerospace ATP, during climb to flight level (FL) 160 in icing conditions, experienced a significant degradation of performance due to propeller icing accompanied by severe vibration that rendered the electronic flight instruments partially unreadable. As the aircraft descended below cloud, control was regained and the flight continued uneventfully.
Rotors
On 22 February 2008, a Eurocopter AS332 L2 Super Puma flying from an offshore oil platform to Aberdeen was struck by lightning. There was no apparent consequence and so, although this event required a landing as soon as possible, the commander decided to continue the remaining 165nm to the planned destination which was achieved uneventfully. Main rotor blade damage including some beyond repairable limits was subsequently discovered. The Investigation noted evidence indicating that this helicopter type had a relatively high propensity to sustain lightning strikes but noted that, despite the risk of damage, there was currently no adverse safety trend.
On 22 October 2012, the crew of a Eurocopter EC225 LP on a flight from Aberdeen to an offshore platform received an indication that the main gearbox (MGB) lubrication system had failed. Shortly after selecting the emergency lubrication system, that system also indicated failure and the crew responded in accordance with the QRH drill to “land immediately” by carrying out a successful controlled ditching. The ongoing investigation has found that there had been a mechanical failure within the MGB but that the emergency lubrication system had, contrary to indications, been functioning normally.
On 12 August 2015, a Sikorsky S76C crew on a flight from an offshore platform to Lagos lost control of their aircraft after a sudden uncommanded pitch up, yaw and roll began and 12 seconds later it crashed into water in a suburb of Lagos killing both pilots and four of the 10 passengers. The Investigation concluded that the upset had been caused by a critical separation within the main rotor cyclic control system resulting from undetected wear at a point where there was no secondary mechanical locking system such as a locking pin or a wire lock to maintain system integrity.
On 27 October 2018, a single pilot Augusta Westland AW169 lifted off from within the Leicester City Football Club Stadium, but after a failure of the tail rotor control system, a loss of yaw control occurred a few hundred feet above ground. The helicopter began to descend with a high rotation rate and soon afterward impacted the ground and almost immediately caught fire, which prevented those onboard surviving. An Investigation is being conducted by the UK AAIB.
On 28 December 2016, yaw control was lost during touchdown of a Sikorsky S92A landing on a North Sea offshore platform and it almost fell into the sea. The Investigation found that the loss of control was attributable to the failure of the Tail Rotor Pitch Change Shaft bearing which precipitated damage to the associated control servo. It was also found that despite HUMS monitoring being in place, it had been ineffective in proactively alerting the operator to the earlier stages of progressive bearing deterioration which could have ensured the helicopter was grounded for rectification before the accident occurred.
On 3 July 2010, an AW139 helicopter was climbing through 350 feet over Victoria Harbour Hong Kong just after takeoff when the tail rotor detached. A transition to autorotation was accomplished and a controlled ditching followed. All occupants were rescued but some sustained minor injuries. The failure was attributed entirely to manufacturing defects but no corrective manufacturer or regulatory action was taken until two similar accidents had occurred in Qatar (non-fatal) and Brazil (fatal) the following year and two interim Safety Recommendations were issued from this Investigation after which a comprehensive review of the manufacturing process led to numerous changes.
On 22 December 2008, a Boeing 757-200 on a scheduled passenger flight departing Las Vegas for New York JFK experienced sudden failure of the right engine as take off thrust was set and the aircraft was stopped on the runway for fire services inspection. Fire service personnel observed a hole in the bottom of the right engine nacelle and saw a glow inside so they discharged a fire bottle into the nacelle through the open pressure relief doors. In the absence of any contrary indications, this action was considered to have extinguished any fire and the aircraft was then taxied back to the gate on the remaining serviceable engine for passenger disembarkation. None of the 263 occupants were injured but the affected engine suffered significant damage.
On 19 May 2004, a Bombardier DHC8-400 being operated on a scheduled passenger flight from Sandefjord to Bergen by Norwegian airline Wideroe was climbing through 13500 feet approximately 20nm west north west of Sandefjord in day VMC when there was a loud 'bang' from the left engine followed quickly by total power failure and a fire warning for that engine. The crew carried out the QRH drill, declared an emergency and made a return to Sandefjord. Although the left hand engine was shut down and both engine fire bottles had been discharged, the engine warning remained illuminated throughout the remainder of the flight. The aircraft was stopped on the runway after landing and a successful emergency evacuation of all 31 occupants was carried out with no injuries whilst the Airport Fire Service attended to the fire source.
On 8 January 1989, the crew of a British Midland Boeing 737-400 lost control of their aircraft due to lack of engine thrust shortly before reaching a planned en route diversion being made after an engine malfunction and it was destroyed by terrain impact with fatal or serious injuries sustained by almost all the occupants. The crew response to the malfunction had been followed by their shutdown of the serviceable rather the malfunctioning engine. The Investigation concluded that the accident was entirely the consequence of inappropriate crew response to a non-critical loss of powerplant airworthiness.
Engine - General
On 14 September 2021 the crew of a Saab S340B being used for type conversion training purposes were unable to cross start the left engine after it had been temporarily shut down to demonstrate single engine handling performance because the right starter-generator failed. A MAYDAY was declared and after prompt electrical load shedding, sufficient battery power remained to complete a successful diversion. The starter-generator failure was suspected to be attributable to its use whilst in service with a previous operator to support multiple starts at intervals which were insufficient to allow the unit to cool.
On 3 January 2019, a Boeing 737-500 en-route to Port Harcourt experienced signs of intermittent distress to an engine which subsequently failed during final approach there. After a mismanaged initial response before and after a go around, the failed engine was eventually shut down. After a delay of about 20 minutes, an attempted second approach was discontinued when it could not be stabilised. A third approach was then successfully completed. The engine was damaged beyond economic repair and the Investigation found that the operator had been aware of the intermittent malfunction of both engines over several months but ignored it.
On 5 August 2019, an Airbus A321 crew declared a MAYDAY immediately after clearing the landing runway at Valencia when a hold smoke warning was annunciated. An emergency evacuation was completed without injuries. This warning followed “white smoke” from the air conditioning system entering both the passenger cabin and flight deck in the four minutes before landing which had prompted the pilots to don oxygen masks. The Investigation found the white smoke was the direct consequence of an oil leak from the right engine as a result of the misalignment and breakage of a bearing and its associated hydraulic seal.
On 21 January 2019, a Piper PA46-310P en-route north northwest of Guernsey was reported missing and subsequently confirmed to have broken up in flight during an uncontrolled descent. The Investigation found that neither the pilot nor the aircraft involved were able to be used for commercial passenger flight operations but also found that although the direct cause of loss of control was unproven, it was most likely the consequence of carbon monoxide poisoning originating from an exhaust system leak. The safety implications arising from operation of private flights for commercial passenger transport purposes contrary to regulatory requirements were also highlighted.
On 20 February 2021, a PW4077-powered Boeing 777-200 was climbing through 12,500 feet after takeoff from Denver when there was a sudden uncontained failure of the right engine. The associated fire did not fully extinguish in response to the prescribed non-normal procedure and on completion of a return to land, it was fully extinguished before the aircraft could be towed in for passenger disembarkation. The Investigation has already established that the failure originated in a single fan blade within which internal fatigue cracking had been initiated. All operators of 777s powered by PW4000 series engines have grounded their fleets indefinitely.
On 23 October 2020, an Airbus A320 taking off from Brisbane became difficult to keep on the centreline as speed increased and takeoff was rejected from a low speed. It remained on the runway and messages indicating a malfunctioning right engine were then seen. The Investigation found that one engine had surged as thrust was applied due to damage caused by a screwdriver tip inadvertently left in the engine during routine maintenance and that the pilot flying had used the rudder when attempting to maintain directional control during the reject despite its known ineffectiveness for this purpose at low speeds.
On 6 March 2018, smoke was detected coming from flight deck and passenger cabin air conditioning vents of an en-route Bombardier DHC8-400. A MAYDAY was declared to ATC but the prescribed response effectively cleared the smoke and no emergency evacuation on landing was deemed necessary. The Investigation found that the smoke was caused by oil leaking into the air conditioning system due to a failed right hand engine seal. The operator subsequently began to implement a recommended engine modification and adopt a system provided by the engine manufacturer to proactively detect such oil leaks before air conditioning systems are contaminated.
On 7 December 2016, the crew of an ATR 42-500 lost control after airworthiness-related complications followed shutdown of the left engine whilst in the cruise and high speed terrain impact followed. The Investigation concluded that three pre-existing faults with the left engine and its propeller control mechanism had led to a loss of power which had necessitated its shutdown but that these faults had then caused much higher left side drag than would normally result from an engine shutdown and made it progressively more difficult to maintain control. Recovery from a first loss of control was followed by another without recovery.
On 31 December 2017, a de Havilland DHC2 floatplane being manoeuvred at low level over Jerusalem Bay shortly after takeoff was observed to enter a steeply banked turn from which it appeared to depart controlled flight and impact the water surface below almost vertically. The Investigation concluded that the aircraft had stalled despite the exemplary proficiency record of the pilot and that in the absence of any other plausible explanation found that the loss of control was likely to have been the effect of an elevated exposure to carbon monoxide found during post mortem toxicology testing.
On 11 November 2019, one of the two PW100 series engines of a Bombardier DHC8-300 failed catastrophically when takeoff power was set prior to brake release. The Investigation found that the power turbine shaft had fractured in two places and all first and second stage power turbine blades had separated from their disks. The shaft failure was found to have been caused by fatigue cracking initiated by corrosion pitting which was assessed as probably the result of prolonged marine low-altitude operations by the aircraft. It was found that this fatigue cracking could increase undetected during service between scheduled inspections.
Engine Fuel and Control
On 31 December 2020, an Airbus A330-200 identified a fuel leak during a routine top-of-climb check but instead of following the prescribed engine shutdown and leak isolation procedure and then landing as soon as possible, the crew had continued on track until diverting to N’Djaména over 90 minutes later by which time nearly six tonnes of fuel was missing. The leak was caused by an incorrectly assembled connection at the pylon/engine interface. The flight crew’s significant procedural non-compliance was identified as having introduced an avoidable fire risk and been indicative of a systemically weak safety culture at the airline concerned.
On 16 March 2020, a PW150A-powered Bombardier DHC8-400 crew declared a PAN and turned back to Port Moresby after abnormal fumes and (much later) some visible ‘smoke’ which had become apparent after takeoff began to intensify causing some passengers breathing difficulties. Once clear of the landing runway, a precautionary rapid disembarkation was completed. The Investigation found that the source of the smoke/fumes was oil leaking from a failed right engine bearing seal. The failure was found to have occurred ahead of the recommended inspection interval for the seal concerned, a risk which engine manufacturer Pratt & Whitney Canada was aware of.
On 18 April 2018, an engine fire warning was annunciated on an Airbus 330-300 which had just taken off from Atlanta. The warning remained after engine shutdown but was eventually replaced by a fire detection caution. Although not visible to the crew, a continued/reignited engine fire was subsequently seen by ATC on final approach and extinguished after landing. The Investigation concluded that the avoidable delay in the return to land had considerably increased the engine and pylon damage and noted that continuation of the fire had been facilitated by hydraulic fluid passing through a valve held partly open by debris.
On 2 July 2015, the left engine of a Bombarier CRJ 700A exiting the runway after landing at Denver caught fire and continued burning after the aircraft had been stopped on the taxiway and the engine shut down. The Investigation found that the fuel supply to the fuel-operated engine performance valve had failed and the quantity of fuel which then leaked had overwhelmed the engine cowl drain capacity and ignited. A history of similar failures was found and this one resulted in the introduction of additional mandatory in-serviced checks pending the replacement of the valve concerned with an improved design.
On 2 March 2018, a Cessna 441 conducting a single-pilot scheduled passenger flight to Broome suffered successive failures of both engines due to fuel exhaustion and a MAYDAY was declared. Unable to reach the destination or any other aerodrome by the time this occurred, an uneventful landing was made on the area’s main highway. The Investigation found that the fuel quantity was over-reading due to water in the fuel tanks, that cross-checking of fuel used versus indicated fuel in tanks was not done and that when the possibility of fuel exhaustion was first indicated, an available diversion was not made.
On 22 August 2019, the left engine of a Boeing 737-800 failed for unknown reasons soon after reaching planned cruise level of FL360 twenty minutes after departing Samos, Greece and two attempted relights during and after descent to FL240 were unsuccessful. Instead of diverting to the nearest suitable airport as required by applicable procedures, the management pilot in command did not declare single engine operation and completed the planned flight to Prague, declaring a PAN to ATC only on entering Czech airspace. The Investigation noted that engine failure was due to fuel starvation after failure of the engine fuel pump.
On 26 February 2020, after a difficult Airbus A321 left engine first flight of the day start, the same happened on the third sector with en-route engine abnormalities then affecting both engines. With no fault found during post flight maintenance inspections and despite similar engine starting problems, both engines then malfunctioned after takeoff from Gatwick. A MAYDAY return followed. Investigation found that the cause was fuel system contamination by addition of approximately 38 times the correct quantity of biocide during earlier scheduled maintenance and that the release of the aircraft to service for the flight had followed inadequate troubleshooting action.
On 8 February 2019, a Convair C131 climbing out of Nassau experienced a right engine propeller control malfunction. The Captain was able to stabilise power and continued the flight to Miami. As descent began, the same engine malfunctioned and was shut down but the left engine then also malfunctioned and, after an emergency declaration, a mishandled ditching followed. This wrecked the aircraft and only the First Officer survived, seriously injured. The Investigation noted that related engine malfunction on the outbound flight had not been recorded or investigated. No wreckage recovery was attempted so engine failure causes were not determined.
On 29 March 2019, both engines of a Boeing 787-8 on descent to Kansai malfunctioned in quick succession causing auto ignition to be triggered by sub-idle engine rpm but thereafter, sufficient thrust was available to safely complete the flight just under half an hour after the dual malfunction. The Investigation found that the cause of these malfunctions had been contamination of the fuel system with abnormally large concentrations of residue which could be reliably traced to a routinely applied biocide and which had solidified and intermittently impeded the transfer of fuel from the tanks to the engines.
On 17 December 2009, a Blue 1 Avro RJ85 experienced progressive fuel starvation during continued flight after the crew had failed to carry out the QRH drill for an abnormal fuel system indication caused by fuel icing. Although hindsight was able to confirm that complete fuel starvation had not been likely, a failure to recognise the risk to fuel system function arising from routine operations in very cold conditions was identified by the subsequent investigation.
Bleed Air
On 18 March 2020, a Fokker 100 en-route to Port Moresby experienced a failure of the cabin pressurisation and air conditioning system due to a complete failure of the bleed air system. An emergency descent and a PAN were declared and a diversion to Madang completed. The Investigation noted unscheduled work on the bleed air system had occurred prior to the departure of the flight and that long running problems with this system had not been satisfactorily resolved until after the investigated occurrence when four malfunctioning components had finally been systematically identified and replaced.
On 15 August 2018, a Boeing 737-300SF crew concerned about a small residual pressure in a bleed air system isolated after a fault occurred en-route then sought and were given non-standard further troubleshooting guidance by company maintenance which, when followed, led directly and indirectly to additional problems including successive incapacitation of both pilots and a MAYDAY diversion. The Investigation found that the aircraft concerned was carrying a number of relevant individually minor undetected defects which meant the initial crew response was not completely effective and prompted a request for in-flight assistance which was unnecessary and led to the further outcomes.
On 23 September 2019, the flight crew of an Airbus A320 on approach to London Heathrow detected strong acrid fumes on the flight deck and after donning oxygen masks completed the approach and landing, exited the runway and shut down on a taxiway. After removing their masks, one pilot became incapacitated and the other unwell and both were taken to hospital. The other occupants, all unaffected, were disembarked to buses. The very comprehensive investigation was unable to establish the origin of the fumes but did identify a number of circumstantial factors which corresponded to those identified in previous similar events.
On 28 February 2019, an Embraer E195 abandoned takeoff from Exeter when fight deck fumes/smoke accompanied thrust applied against the brakes. When informed of similar conditions in the cabin, the Captain ordered an emergency evacuation. Some passengers using the overwing exits re-entered the cabin after becoming confused as to how to leave the wing. The Investigation attributed the fumes to an incorrectly-performed engine compressor wash arising in a context of poorly-managed maintenance and concluded that guidance on overwing exit use had been inadequate and that the 1.8 metre certification height limit for exits without evacuation slides should be reduced.
On 19 October 2012, a Jet2-operated Boeing 737-800 departing Glasgow made a high speed rejected take off when a strange smell became apparent in the flight deck and the senior cabin crew reported what appeared to be smoke in the cabin. The subsequent emergency evacuation resulted in one serious passenger injury. The Investigation was unable to conclusively identify a cause of the smoke and the also- detected burning smells but excess moisture in the air conditioning system was considered likely to have been a factor and the Operator subsequently made changes to its maintenance procedures.
On 5 March 2011, a Finnair Airbus A320 was westbound in the cruise in southern Swedish airspace after despatch with Engine 1 bleed air system inoperative when the Engine 2 bleed air system failed and an emergency descent was necessary. The Investigation found that the Engine 2 system had shut down due to overheating and that access to proactive and reactive procedures related to operations with only a single bleed air system available were deficient. The crew failure to make use of APU air to help sustain cabin pressurisation during flight completion was noted.
On 22 December 2010, a Finnair Airbus A330-300 inbound to Helsinki and cruising in very cold air at an altitude of 11,600 metres lost cabin pressurisation in cruise flight and completed an emergency descent before continuing the originally intended flight at a lower level. The subsequent Investigation was carried out together with that into a similar occurrence to another Finnair A330 which had occurred 11 days earlier. It was found that in both incidents, both engine bleed air systems had failed to function normally because of a design fault which had allowed water within their pressure transducers to freeze.
On 21 February 2017, an Airbus A320 despatched with the APU inoperative experienced successive failures of both air conditioning and pressurisation systems, the second of which occurred at FL300 and prompted the declaration of a MAYDAY and an emergency descent followed by an uneventful diversion to Alicante. The Investigation found that the cause of the dual failure was likely to have been the undetectable and undetected degradation of the aircraft bleed air regulation system and whilst noting a possibly contributory maintenance error recommended that a new scheduled maintenance task to check components in the aircraft type bleed system be established.
On 30 June 2015, both bleed air supplies on a Boeing 737-400 at FL370 failed in quick succession resulting in the loss of all pressurisation and, after making an emergency descent to 10,000 feet QNH, the flight was continued to the planned destination, Kansai. The Investigation found that both systems failed due to malfunctioning pre-cooler control valves and that these malfunctions were due to a previously identified risk of premature deterioration in service which had been addressed by an optional but recommended Service Bulletin which had not been taken up by the operator of the aircraft involved.
On 3 October 2015, an Airbus A320 which had just taken off from Dublin experienced fumes from the air conditioning system in both flight deck and cabin. A 'PAN' was declared and the aircraft returned with both pilots making precautionary use of their oxygen masks. The Investigation found that routine engine pressure washes carried out prior to departure have been incorrectly performed and a contaminant was introduced into the bleed air supply to the air conditioning system as a result. The context for the error was found to be the absence of any engine wash procedure training for the Operator's engineers.
Other
On 11 December 2019, a Bombardier BD700 Global 6000 making a night landing at Liverpool suffered a nose wheel steering failure shortly after touchdown. The crew were unable to prevent the aircraft departing the side of the runway into a grassed area where it stopped, undamaged, in mud. The Investigation found that the crew response was contrary to that needed for continued directional control but also that no pilot training or QRH procedure covered such a failure occurring at high speed nor was adequate guidance available on mitigating the risk of inadvertent opposite brake application during significant rudder deflection.
On 13 April 2019, an experienced Cessna 525 pilot almost lost control shortly after takeoff from Bournemouth when a recently installed performance enhancement system malfunctioned. After a six minute flight involving a potentially hazardous upset and recovery of compromised control, the turn back was successful. The Investigation found that although the pilot was unaware of the supplementary procedures supporting the modification, these did not adequately address possible failure cases. Also, certification flight tests prior to modification approval did not identify the severity of some possible failure outcomes and corresponding Safety Recommendations were made to the system manufacturer and safety regulators.
On 12 October 2018, the crew of a Boeing 737-400 already released to service under MEL conditions with an inoperative No 1 engine generator encountered a loss of services from the No 2 electrical system en-route to East Midlands which created a situation not addressed by QRH procedures. The flight was completed and both the new and existing defects were subsequently rectified relatively easily. The Investigation concluded that the operator involved appeared to be prioritising operational requirements over aircraft serviceability issues and made a range of Safety Recommendations aimed at improving company safety culture and the effectiveness of regulatory oversight.
On 2 November 2017, the flight crew of an Airbus A320 climbing out of Cork detected a “strong and persistent” burning smell and after declaring a MAYDAY returned to Cork where confusing instructions from the crew resulted in a combination of the intended precautionary rapid disembarkation and an emergency evacuation using escape slides. The Investigation highlighted the necessity of clear and unambiguous communications with passengers which distinguish these two options and in particular noted the limitations in currently mandated pre flight briefings for passengers seated at over wing emergency exits.
On 19 June 2016, a BAe 146-300 landed long at Khark Island and overran the end of the runway at speed with the aircraft only stopping because the nose landing gear collapsed on encountering uneven ground. The Investigation attributed the accident - which caused enough structural damage for the aircraft to be declared a hull loss - entirely to the decisions and actions of the aircraft commander who failed to go around from an unstabilised approach, landed long and then did not ensure maximum deceleration was achieved. The monitoring role of the low experience First Officer was ineffective.
On 11 February 2017, a Cessna 402 failed to stop on the runway when landing at Virgin Gorda and was extensively damaged. The Investigation noted that the landing distance required was very close to that available with no safety margin so that although touchdown was normal, when the brakes failed to function properly, there was no possibility of safely rejecting the landing or stopping normally on the runway. Debris in the brake fluid was identified as causing brake system failure. The context was considered as the Operator s inadequate maintenance practices and a likely similar deficiency in operational procedures and processes.
On 30 June 2015 the crew of an en route Embraer 170 failed to notice that their transponder had reverted to Standby and the ATC response, which involved cross border coordination, was so slow that the aircraft was not informed of the loss of its transponder signal for over 30 minutes by which time it had already passed within 0.9nm of an unseen Dassault Falcon 900 at the same level. The Investigation found that the Embraer crew had failed to follow appropriate procedures and that the subsequent collision risk had been significantly worsened by a muddled and inappropriate ATC response.
On 17 July 1996, a Boeing 747, operated by TWA, experienced an in-flight breakup and then crashed into the Atlantic Ocean near East Moriches, New York, USA.
On 19 November 1996, a Beech 1900C which had just landed and a Beech King Air A90 which was taking off collided at the intersection of two runways at the non-Towered Quincy Municipal Airport. Both aircraft were destroyed by impact forces and fire and all occupants of both aircraft were killed. The Investigation found that the King Air pilots had failed to monitor the CTAF or properly scan visually for traffic. The loss of life of the Beech 1900 occupants, who had probably survived the impact, was attributed largely to inability to open the main door of the aircraft.
On 8 January 2003, a DHC8-400 sustained multiple bird strikes during a night visual circuit at the Medford airport, OR, USA, resulting in loss of flight displays, multiple false system warnings and the shattering of the LH windscreen. The Captain sustained significant facial injuries and temporary incapacitation with a successful approach and landing being completed by the co-pilot.
Emergency Evacuation
On 12 March 2009, a Sikorsky S-92A crew heading offshore from St. John's, Newfoundland declared an emergency and began a return after total loss of main gear box oil pressure but lost control during an attempted ditching. The Investigation found that all oil had been lost after two main gear box securing bolts had sheared. It was noted that ambiguity had contributed to crew misdiagnosis the cause and that the ditching had been mishandled. Sea States beyond the capability of Emergency Flotation Systems and the limited usefulness of personal Supplemental Breathing Systems in cold water were identified as Safety Issues.
On 8 March 2017, a Boeing MD83 departing Ypsilanti could not be rotated and the takeoff had to be rejected from above V1. The high speed overrun which followed substantially damaged the aircraft but evacuation was successful. The Investigation found that the right elevator had been locked in a trailing-edge-down position as a result of damage caused to the aircraft by high winds whilst it was parked unoccupied for two days prior to the takeoff. It was noted that on an aircraft with control tab initiated elevator movement, this condition was undetectable during prevailing pre flight system inspection or checks.
On 4 October 2014, the fracture of a hydraulic hose during an A330-200 pushback at night at Karachi was followed by dense fumes in the form of hydraulic fluid mist filling the aircraft cabin and flight deck. After some delay, during which a delay in isolating the APU air bleed exacerbated the ingress of fumes, the aircraft was towed back onto stand and an emergency evacuation completed. During the return to stand, a PBE unit malfunctioned and caught fire when one of the cabin crew attempted to use it which prevented use of the exit adjacent to it for evacuation.
On 22 August 2015 the pilot of a civil-operated Hawker Hunter carrying out a flying display sequence at Shoreham failed to complete a loop and partial roll manoeuvre and the aircraft crashed into road traffic unrelated to the airshow and exploded causing multiple third party fatalities and injuries. The Investigation found that the pilot had failed to enter the manoeuvre correctly and then failed to abandon it when it should have been evident that it could not be completed. It was concluded that the wider context for the accident was inadequate regulatory oversight of UK civil air display flying risk management.
On 31 October 2014, indications of a malfunction of the right over wing emergency exit slide on take off were followed during the return to land by the complete detachment of the slide and un-commanded but controllable roll. The Investigation found that a series of technical issues with the slide panel and carrier locking devices caused the slide carrier to deploy and the slide to unravel. Although an SB existed to address some of these issues, it had not been actioned on the aircraft. Two operational matters encountered during the Investigation were the subject of Safety Recommendations.
On 3 July 2010, an AW139 helicopter was climbing through 350 feet over Victoria Harbour Hong Kong just after takeoff when the tail rotor detached. A transition to autorotation was accomplished and a controlled ditching followed. All occupants were rescued but some sustained minor injuries. The failure was attributed entirely to manufacturing defects but no corrective manufacturer or regulatory action was taken until two similar accidents had occurred in Qatar (non-fatal) and Brazil (fatal) the following year and two interim Safety Recommendations were issued from this Investigation after which a comprehensive review of the manufacturing process led to numerous changes.
On 22nd August 1985, a B737-200 being operated by British Airtours, a wholly-owned subsidiary of British Airways, suffered an uncontained engine failure, with consequent damage from ejected debris enabling the initiation of a fuel-fed fire which spread to the fuselage during the rejected take off and continued to be fuel-fed after the aircraft stopped, leading to rapid destruction of the aircraft before many of the occupants had evacuated.
On 14 January 2002, a Boeing 737-200, operated by Lion Air, attempted to complete a daylight take off from Pekanbaru, Indonesia without flaps set after a failure to complete the before take off checks. The rejected take off was not initiated promptly and the aircraft overran the runway. The take off configuration warning failed to sound because the associated circuit breaker was so worn that it had previously auto-tripped and this had not been noticed.
On 16 May 1995, an RAF BAe Nimrod on an airworthiness function flight caught fire after an electrical short circuit led indirectly to the No 4 engine starter turbine disc being liberated and breaching the No 2 fuel tank. It was concluded by the Investigation that the leaking fuel had then been ignited by either the electrical arcing or the heat of the adjacent engine. After the fire spread rapidly, the risk of structural break up led the commander to ditch the aircraft whilst it was still controllable. This was successful and all seven occupants were rescued.
Rotary Aircraft Transmission
On 12 March 2009, a Sikorsky S-92A crew heading offshore from St. John's, Newfoundland declared an emergency and began a return after total loss of main gear box oil pressure but lost control during an attempted ditching. The Investigation found that all oil had been lost after two main gear box securing bolts had sheared. It was noted that ambiguity had contributed to crew misdiagnosis the cause and that the ditching had been mishandled. Sea States beyond the capability of Emergency Flotation Systems and the limited usefulness of personal Supplemental Breathing Systems in cold water were identified as Safety Issues.
On 29 April 2016, an Airbus EC225 Super Puma main rotor detached without warning en-route to Bergen. Control was lost and it crashed and was destroyed. Rotor detachment was attributed to undetected development of metal fatigue in the same gearbox component which caused an identical 2009 accident to a variant of the same helicopter type. Despite this previous accident, the failure mode involved had not been properly understood or anticipated. The investigation identifies significant lessons to be learned related to gearbox design, risk assessment, fatigue evaluation, gearbox condition monitoring, type certification and continued airworthiness, which may also be valid for other helicopter types.
Group 2 - Contributors
Maintenance Error (valid guidance available)
On 6 August 2021, an Airbus A319 experienced uncommanded loss of both Flight Directors and the Flight Mode Annunciator and disconnection of both autopilot and autothrust in the climb. After levelling at FL350, significant inertial reference position inconsistencies were observed. A precautionary PAN was declared and the flight was completed. Investigation found that the cause was a momentary abnormal vertical shock load transferred to Inertial Reference System equipment through an overextended nose gear shock absorber by a sharp jolt during takeoff caused by a runway patch repair. Sensitivity of the particular inertial reference system installed on the aircraft was noted.
On 1 June 2019, a Boeing 787-8 lost all cabin air conditioning after both packs failed less than an hour from its destination, Narita. When the Cabin Altitude reached 10,000 feet, the descent already commenced was completed as an emergency descent and the flight thereafter was without further event. The Investigation found that although an amended non normal procedure restricting pack resets to a maximum altitude of 35000 feet had been issued almost two months earlier, it was still “under review” at the operator which has since amended their procedures for assessing manufacturer communications which have operational safety implications.
On 29 September 2017, the crew of an Airbus A320 detected a smell of burning plastic and simultaneously observed black smoke entering the flight deck near the right side rudder pedals. Completion of appropriate response procedures reduced the smoke and a diversion to Athens with a MAYDAY declared was without further event. The origin of the smoke and fumes was traced to the failure of the static inverter which was part of a batch which had been previously notified as faulty but not identified as such by the aircraft operator’s maintenance organisation which has since modified its relevant procedures.
On 7 December 2016, the crew of an ATR 42-500 lost control after airworthiness-related complications followed shutdown of the left engine whilst in the cruise and high speed terrain impact followed. The Investigation concluded that three pre-existing faults with the left engine and its propeller control mechanism had led to a loss of power which had necessitated its shutdown but that these faults had then caused much higher left side drag than would normally result from an engine shutdown and made it progressively more difficult to maintain control. Recovery from a first loss of control was followed by another without recovery.
On 31 December 2017, a de Havilland DHC2 floatplane being manoeuvred at low level over Jerusalem Bay shortly after takeoff was observed to enter a steeply banked turn from which it appeared to depart controlled flight and impact the water surface below almost vertically. The Investigation concluded that the aircraft had stalled despite the exemplary proficiency record of the pilot and that in the absence of any other plausible explanation found that the loss of control was likely to have been the effect of an elevated exposure to carbon monoxide found during post mortem toxicology testing.
On 15 November 2018, a Bombardier DHC8-300 made a main gear only touchdown at Stephenville with only minor damage after diverting there when the nose landing gear only partially extended when routinely selected on approach at the originally intended destination. The Investigation found that the cause was incorrect nose gear assembly which had allowed hydraulic fluid to leak and eventually led to it jamming. There was some concern at the way the flight was conducted following the problem which involved continuous smartphone communications with the operator and an overspeed which it was considered constituted an avoidable risk to safety.
On 26 February 2020, after a difficult Airbus A321 left engine first flight of the day start, the same happened on the third sector with en-route engine abnormalities then affecting both engines. With no fault found during post flight maintenance inspections and despite similar engine starting problems, both engines then malfunctioned after takeoff from Gatwick. A MAYDAY return followed. Investigation found that the cause was fuel system contamination by addition of approximately 38 times the correct quantity of biocide during earlier scheduled maintenance and that the release of the aircraft to service for the flight had followed inadequate troubleshooting action.
On 29 March 2019, both engines of a Boeing 787-8 on descent to Kansai malfunctioned in quick succession causing auto ignition to be triggered by sub-idle engine rpm but thereafter, sufficient thrust was available to safely complete the flight just under half an hour after the dual malfunction. The Investigation found that the cause of these malfunctions had been contamination of the fuel system with abnormally large concentrations of residue which could be reliably traced to a routinely applied biocide and which had solidified and intermittently impeded the transfer of fuel from the tanks to the engines.
On 1 March 2019, an Airbus A320 left engine suffered a contained failure soon after takeoff thrust was set for a night departure from London Stansted but despite the absence of an instruction to cabin crew to begin an evacuation, they did so anyway just before the aircraft was going to be taxied clear of the runway with the Captain only aware when passengers were seen outside the aircraft. The Investigation found that an evacuation had been ordered by the senior member of the cabin crew after she was “overwhelmed” by the situation and believed her team members were “scared”.
On 16 November 2012, an Air Contractors Airbus A300 departed the left the side of the landing runway at Bratislava after an abnormal response to directional control inputs. Investigation found that incorrect and undetected re-assembly of the nose gear torque links had led to the excursion and that absence of clear instructions in maintenance manuals, since rectified, had facilitated this. It was also considered that the absence of any regulation requiring equipment in the vicinity of the runway to be designed to minimise potential damage to aircraft departing the paved surface had contributed to the damage caused by the accident.
Maintenance Error (invalid guidance available)
On 25 March 2018, an ATR 42-500 main landing gear bay door weighing 15 kg detached shortly after a night descent had begun but this was unknown until the flight arrived at Aurillac. The Investigation found that the root cause of the detachment was a loose securing nut which had triggered a sequence of secondary failures within a single flight which culminated in the release of the door. It was concluded that the event highlighted specific and systemic weakness in relevant airworthiness documentation and practice in relation to the lost door and the use of fasteners on this aircraft type generally.
On 28 February 2019, an Embraer E195 abandoned takeoff from Exeter when fight deck fumes/smoke accompanied thrust applied against the brakes. When informed of similar conditions in the cabin, the Captain ordered an emergency evacuation. Some passengers using the overwing exits re-entered the cabin after becoming confused as to how to leave the wing. The Investigation attributed the fumes to an incorrectly-performed engine compressor wash arising in a context of poorly-managed maintenance and concluded that guidance on overwing exit use had been inadequate and that the 1.8 metre certification height limit for exits without evacuation slides should be reduced.
On 31 January 2011, a Singapore Airlines Airbus A380-800 was in the cruise when there was sudden loud noise and signs of associated electrical smoke and potential burning in a toilet compartment with a corresponding ECAM smoke alert. After a fire extinguisher had been discharged into the apparent source, there were no further signs of fire or smoke. Subsequent investigation found signs of burning below the toilet floor and it was concluded that excessive current caused by a short circuit which had resulted from a degraded cable had been the likely cause, with over current protection limiting the damage caused by overheating.
On 19 October 2012, a Jet2-operated Boeing 737-800 departing Glasgow made a high speed rejected take off when a strange smell became apparent in the flight deck and the senior cabin crew reported what appeared to be smoke in the cabin. The subsequent emergency evacuation resulted in one serious passenger injury. The Investigation was unable to conclusively identify a cause of the smoke and the also- detected burning smells but excess moisture in the air conditioning system was considered likely to have been a factor and the Operator subsequently made changes to its maintenance procedures.
On 10 January 2011, a Europe Airpost Boeing 737-300 taking off from Montpelier after repainting had just rotated for take off when the leading edge slats extended from the Intermediate position to the Fully Extended position and the left stick shaker was activated as a consequence of the reduced stalling angle of attack. Initial climb was sustained and soon afterwards, the slats returned to their previous position and the stick shaker activation stopped. The unexpected configuration change was attributed to paint contamination of the left angle of attack sensor, the context for which was inadequate task guidance.
On 23 July 2011, a Boeing 737-300 being operated by Jet2.com on a passenger flight from Leeds/Bradford to Paris CDG experienced violent vibration from the main landing gear at touch down in normal day visibility on runway 27R at a normal speed off a stabilised approach. This vibration was accompanied by lateral acceleration that made directional control difficult but the aircraft was kept on the runway and at a speed of 75 knots, the vibrations abruptly stopped. Once clear of the runway, the aircraft was stopped and the engines shutdown prior to a tow to the gate. None of the 133 occupants were injured.
On 27 March 2016 an ATR 42-500 had just departed Esbjerg when the right engine flamed out. It was decided to complete the planned short flight to Billund but on the night IMC approach there, the remaining engine malfunctioned and lost power. The approach was completed and the aircraft evacuated after landing. The Investigation found the left engine failed due to fuel starvation resulting from a faulty fuel quantity indication probably present since recent heavy maintenance and that the right engine had emitted flames during multiple compressor stalls to which it was vulnerable due to in-service deterioration and hot section damage.
On 7 July 2016, a right engine fire warning was annunciated as a Boeing 757-200 got airborne from New York JFK and after shutting the engine down in accordance with the corresponding checklist, an emergency declaration was followed by an immediate and uneventful return to land. After an external inspection confirmed there was no sign of an active fire, the aircraft was taxied to a terminal gate for normal disembarkation. The Investigation found that a fuel-fed fire had occurred because an O-ring had been incorrectly installed on a fuel tube during maintenance prior to the flight.
On 9 September 2012, the crew of a DHC8-300 climbing out of Abu Dhabi declared a PAN and returned after visual evidence of the right engine overheating were seen from the passenger cabin. The Investigation found that the observed signs of engine distress were due to hot gas exiting through the cavity left by non-replacement of one of the two sets of igniters on the engine after a pressure wash carried out overnight prior to the flight and that the left engine was similarly affected. The context for the error was identified as a dysfunctional maintenance organisation at the Operator.
On 31 October 2012, the crew of an ATR42 on a handover airworthiness function flight out of Prague briefly lost control in a full stall with significant wing drop after continuing a prescribed Stall Protection System (SPS) test below the appropriate speed and then failing to follow the correct stall recovery procedure. Failure of the attempted SPS test was subsequently attributed to both AOA vanes having become contaminated with water during earlier aircraft repainting at a specialist contractor and consequently being constrained in a constant position whilst the SPS test was being conducted at well above the prevailing freezing level.
Inadequate Maintenance Schedule
On 7 June 2021 an Embraer ERJ170 had just commenced its descent towards destination when both primary and secondary pitch trim systems failed resulting in excessive nose-down pitch control forces and an inoperative autopilot. The flight was completed without further event with the Pilot Flying using both hands on the control yoke to control pitch attitude manually. During the landing roll the nosewhweel steering system also failed. The pitch trim failure was attributed to probable jamming of the trim actuator due to water, possibly condensation, freezing within it. The steering system fault was attributed to a completely unrelated sensor failure.
On 2 July 2015, the left engine of a Bombarier CRJ 700A exiting the runway after landing at Denver caught fire and continued burning after the aircraft had been stopped on the taxiway and the engine shut down. The Investigation found that the fuel supply to the fuel-operated engine performance valve had failed and the quantity of fuel which then leaked had overwhelmed the engine cowl drain capacity and ignited. A history of similar failures was found and this one resulted in the introduction of additional mandatory in-serviced checks pending the replacement of the valve concerned with an improved design.
On 23 February 2020, a Bombardier Challenger 605 making a flapless landing after a system failure during descent briefly lost control when reverse thrust selection after a normal touchdown was followed by the aircraft becoming airborne before stick push activation was followed by a hard second touchdown. Structural and abrasion fuselage damage was caused. The Investigation attributed the flap failure to corrosion within the specified maintenance inspection interval and the brief loss of control during landing to a combination of inadequate crew preparation for the landing and the fact that simulator replication of aircraft handling did not correspond to reality.
On 11 November 2019, one of the two PW100 series engines of a Bombardier DHC8-300 failed catastrophically when takeoff power was set prior to brake release. The Investigation found that the power turbine shaft had fractured in two places and all first and second stage power turbine blades had separated from their disks. The shaft failure was found to have been caused by fatigue cracking initiated by corrosion pitting which was assessed as probably the result of prolonged marine low-altitude operations by the aircraft. It was found that this fatigue cracking could increase undetected during service between scheduled inspections.
On 7 December 2016, the crew of an ATR 42-500 lost control after airworthiness-related complications followed shutdown of the left engine whilst in the cruise and high speed terrain impact followed. The Investigation concluded that three pre-existing faults with the left engine and its propeller control mechanism had led to a loss of power which had necessitated its shutdown but that these faults had then caused much higher left side drag than would normally result from an engine shutdown and made it progressively more difficult to maintain control. Recovery from a first loss of control was followed by another without recovery.
On 31 December 2017, a de Havilland DHC2 floatplane being manoeuvred at low level over Jerusalem Bay shortly after takeoff was observed to enter a steeply banked turn from which it appeared to depart controlled flight and impact the water surface below almost vertically. The Investigation concluded that the aircraft had stalled despite the exemplary proficiency record of the pilot and that in the absence of any other plausible explanation found that the loss of control was likely to have been the effect of an elevated exposure to carbon monoxide found during post mortem toxicology testing.
On 10 January 2011, an Air Atlanta Icelandic Airbus A300-600 on a scheduled cargo flight made a bounced touchdown at East Midlands and then attempted a go around involving retraction of the thrust reversers after selection out and before they had fully deployed. This prevented one engine from spooling up and, after a tail strike during rotation, the single engine go around was conducted with considerable difficulty at a climb rate only acceptable because of a lack of terrain challenges along the climb out track.
On 23 July 2011, a Boeing 737-300 being operated by Jet2.com on a passenger flight from Leeds/Bradford to Paris CDG experienced violent vibration from the main landing gear at touch down in normal day visibility on runway 27R at a normal speed off a stabilised approach. This vibration was accompanied by lateral acceleration that made directional control difficult but the aircraft was kept on the runway and at a speed of 75 knots, the vibrations abruptly stopped. Once clear of the runway, the aircraft was stopped and the engines shutdown prior to a tow to the gate. None of the 133 occupants were injured.
On 2 July 2014, a Fokker 50 fully loaded - and probably overloaded - with a cargo of qat crashed into a building and was destroyed soon after its night departure from Nairobi after failing to climb due to a left engine malfunction which was evident well before V1. The Investigation attributed the accident to the failure of the crew to reject the takeoff after obvious malfunction of the left engine soon after they had set takeoff power which triggered a repeated level 3 Master Warning that required an automatic initiation of a rejected takeoff.
On 2 November 2017, the flight crew of an Airbus A320 climbing out of Cork detected a “strong and persistent” burning smell and after declaring a MAYDAY returned to Cork where confusing instructions from the crew resulted in a combination of the intended precautionary rapid disembarkation and an emergency evacuation using escape slides. The Investigation highlighted the necessity of clear and unambiguous communications with passengers which distinguish these two options and in particular noted the limitations in currently mandated pre flight briefings for passengers seated at over wing emergency exits.
Inadequate Maintenance Inspection
On 8 July 2019, a loud bang was heard following intermediate flap selection on a Boeing 747-400F making an approach to Harare and a concurrent uncommanded right roll was countered with left aileron. The flight was completed without further event but a post-flight inspection found part of the inboard section of the right wing flap assembly was missing and the right fuselage impact-damaged in several places. The missing flap section measuring 3.7 metres by 0.6 metres was recovered with detachment attributed to undetected fatigue cracking already present at component installation. A long history of problems with 747 flaps was noted.
On 18 March 2020, a Fokker 100 en-route to Port Moresby experienced a failure of the cabin pressurisation and air conditioning system due to a complete failure of the bleed air system. An emergency descent and a PAN were declared and a diversion to Madang completed. The Investigation noted unscheduled work on the bleed air system had occurred prior to the departure of the flight and that long running problems with this system had not been satisfactorily resolved until after the investigated occurrence when four malfunctioning components had finally been systematically identified and replaced.
On 2 July 2015, the left engine of a Bombarier CRJ 700A exiting the runway after landing at Denver caught fire and continued burning after the aircraft had been stopped on the taxiway and the engine shut down. The Investigation found that the fuel supply to the fuel-operated engine performance valve had failed and the quantity of fuel which then leaked had overwhelmed the engine cowl drain capacity and ignited. A history of similar failures was found and this one resulted in the introduction of additional mandatory in-serviced checks pending the replacement of the valve concerned with an improved design.
On 22 September 2021, a Boeing 787-9 was found on arrival at its destination, Los Angeles, to have completed the 14½ hour flight from Melbourne with all four fan cowl static ports taped over. The crew had not observed any adverse consequence. The Investigation attributed the oversight to inadequate pre-flight maintenance and operational procedures and found that failure to identify the taping had resulted in the aircraft departing with reduced redundancy to the engine electronic control systems of both engines.
On 6 February 1996, a Boeing 757-200 took off from Puerto Plata at night despite awareness at the 80 knot check that the Captains altimeter was not working. Thereafter, the crew became confused as to their actual airspeed and lost control before the aircraft hit the sea surface less than five minutes after takeoff. The Investigation found that the Captain’s pitot probe was blocked and that the three pilots on the flight deck had become confused about which airspeed indications were reliable and had then not recovered from an aerodynamic stall which followed the wholly avoidable mismanagement of the aircraft flight path.
On 7 February 2018, a Boeing 737-800 experienced an airspeed mismatch during takeoff on a post maintenance positioning flight but having identified the faulty system by reference to the standby instrumentation, the intended flight was completed without further event. After the recorded defect was then signed off as “no fault found” after a failure to follow the applicable fault-finding procedure, the same happened on the next (revenue) flight but with an air turnback made. The Investigation found that the faulty sensor had been fitted at build three earlier with a contaminated component which had slowly caused sensor malfunction to develop.
On 26 February 2020, after a difficult Airbus A321 left engine first flight of the day start, the same happened on the third sector with en-route engine abnormalities then affecting both engines. With no fault found during post flight maintenance inspections and despite similar engine starting problems, both engines then malfunctioned after takeoff from Gatwick. A MAYDAY return followed. Investigation found that the cause was fuel system contamination by addition of approximately 38 times the correct quantity of biocide during earlier scheduled maintenance and that the release of the aircraft to service for the flight had followed inadequate troubleshooting action.
On 13 April 2013, an Air France Airbus A330-200 was damaged during a hard (2.74 G) landing at Caracas after the aircraft commander continued despite the aircraft becoming unstabilised below 500 feet agl with an EGPWS ‘SINK RATE’ activation beginning in the flare. Following a superficial inspection, maintenance personnel determined that no action was required and released the aircraft to service. After take off, it was impossible to retract the landing gear and the aircraft returned. Considerable damage from the earlier landing was then found to both fuselage and landing gear which had rendered the aircraft unfit to fly.
On 12 March 2009, a Sikorsky S-92A crew heading offshore from St. John's, Newfoundland declared an emergency and began a return after total loss of main gear box oil pressure but lost control during an attempted ditching. The Investigation found that all oil had been lost after two main gear box securing bolts had sheared. It was noted that ambiguity had contributed to crew misdiagnosis the cause and that the ditching had been mishandled. Sea States beyond the capability of Emergency Flotation Systems and the limited usefulness of personal Supplemental Breathing Systems in cold water were identified as Safety Issues.
On 1 April 2011, a Southwest Boeing 737-300 climbing through FL340 experienced a sudden loss of pressurisation as a section of fuselage crown skin ruptured. A successful emergency descent was made with a diversion to Yuma, where the aircraft landed half an hour later. Investigation found that the cause of the failure was an undetected manufacturing fault in the 15 year-old aircraft. One member of the cabin crew and an off duty staff member who tried to assist him became temporarily unconscious after disregarding training predicated on the time of useful consciousness after sudden depressurisation.
Inadequate QRH Drills
On 12 March 2009, a Sikorsky S-92A crew heading offshore from St. John's, Newfoundland declared an emergency and began a return after total loss of main gear box oil pressure but lost control during an attempted ditching. The Investigation found that all oil had been lost after two main gear box securing bolts had sheared. It was noted that ambiguity had contributed to crew misdiagnosis the cause and that the ditching had been mishandled. Sea States beyond the capability of Emergency Flotation Systems and the limited usefulness of personal Supplemental Breathing Systems in cold water were identified as Safety Issues.
On 21 November 2006, the crew of a Bristow Eurocopter AS332 L2 making an unscheduled passenger flight from an offshore platform to Den Helder in night VMC decided to ditch their aircraft after apparent malfunction of an engine and the flight controls were perceived as rendering it unable to safely complete the flight. All 17 occupants survived but the evacuation was disorganised and both oversight of the operation by and the actions of the crew were considered to have been inappropriate in various respects. Despite extensive investigation, no technical fault which would have rendered it unflyable could be confirmed.
On 19 August 2012, the crew of a Flybe Finland ATR 72-200 approaching Helsinki failed to respond appropriately to a fault which limited rudder travel and were then unable to maintain directional control after touchdown with a veer off the runway then following. It was concluded that as well as prioritising a continued approach over properly dealing with the annunciated caution, crew technical knowledge in respect of the fault encountered had been poor and related training inadequate. Deficiencies found in relevant aircraft manufacturer operating documentation were considered to have been a significant factor and Safety Recommendations were made accordingly.
On 5 March 2011, a Finnair Airbus A320 was westbound in the cruise in southern Swedish airspace after despatch with Engine 1 bleed air system inoperative when the Engine 2 bleed air system failed and an emergency descent was necessary. The Investigation found that the Engine 2 system had shut down due to overheating and that access to proactive and reactive procedures related to operations with only a single bleed air system available were deficient. The crew failure to make use of APU air to help sustain cabin pressurisation during flight completion was noted.
On 6 November 2019, the crew of an Embraer E175LR which had just taken off from Atlanta experienced difficulty in maintaining pitch control after an apparent pitch trim runaway and an emergency was declared. Control was subsequently regained and a return to land was made without further problems. The Investigation is continuing but has identified the root cause as wiring damage arising from incorrect installation, noted that potentially related corrective action was not mandated and determined that the operator’s QRH drill for the situation encountered had significantly contained only one memory action rather the two in the aircraft manufacturer’s version.
On 26 June 2016, thick white smoke suddenly appeared in the cabin of a fully loaded Airbus A330-300 prior to engine start with the door used for boarding still connected to the air bridge. An emergency evacuation initiated by cabin crew was accomplished without injury although amidst some confusion due to a brief conflict between flight crew and cabin crew instructions. The Investigation found that the smoke had been caused when an APU seal failed and hot oil entered the bleed air supply and pyrolysed. Safety Recommendations in respect of both crew communication and procedures and APU auto-shutdown were made.
On 12 September 2013, pressurisation control failed in an A320 after a bleed air fault occurred following dispatch with one of the two pneumatic systems deactivated under MEL provisions. The Investigation found that the cause of the in-flight failure was addressed by an optional SB not yet incorporated. Also, relevant crew response SOPs lacking clarity and a delay in provision of a revised MEL procedure meant that use of the single system had not been optimal and after a necessary progressive descent to FL100 was delayed by inadequate ATC response, and ATC failure to respond to a PAN call required it to be upgraded to MAYDAY.
On 5 January 2014, an Airbus A380-800 en route to Singapore at night made an emergency descent and diversion to Baku after a loss of cabin pressure without further event. The Investigation attributed the pressure loss to a fatigue crack in a door skin which was initiated due to a design issue with door Cover Plates, which had not been detected when the Cover Plate was replaced with an improved one eighteen months earlier. Safety Issues related to cabin crew use of emergency oxygen and diversions to aerodromes with a fire category less than that normally required were also identified.
On 5 June 2015, a DHC8-200 descending towards Bradley experienced an in-flight fire which originated at a windshield terminal block. Attempts to extinguish the fire were unsuccessful with the electrical power still selected to the circuit. However, the fire eventually stopped and only smoke remained. An emergency evacuation was carried out after landing. The Investigation was unable to establish the way in which the malfunction that caused the fire arose but noted the continuing occurrence of similar events on the aircraft type and five Safety Recommendations were made to Bombardier to address the continuing risk.
On 26 February 2013, the crew of a Boeing 752 temporarily lost full control of their aircraft on a night auto-ILS approach at Keflavik when an un-commanded roll occurred during flap deployment after an earlier partial loss of normal hydraulic system pressure. The origin of the upset was found to have been a latent fatigue failure of a roll spoiler component, the effect of which had only become significant in the absence of normal hydraulic pressure and had been initially masked by autopilot authority until this was exceeded during flap deployment.
OEM Design fault
On 31 December 2020, an Airbus A330-200 identified a fuel leak during a routine top-of-climb check but instead of following the prescribed engine shutdown and leak isolation procedure and then landing as soon as possible, the crew had continued on track until diverting to N’Djaména over 90 minutes later by which time nearly six tonnes of fuel was missing. The leak was caused by an incorrectly assembled connection at the pylon/engine interface. The flight crew’s significant procedural non-compliance was identified as having introduced an avoidable fire risk and been indicative of a systemically weak safety culture at the airline concerned.
On 1 August 2019, an Airbus A320 annunciated an abnormal gear status indication when retraction was attempted after takeoff. Soon afterwards, an aircraft part was observed by an aircraft following the same taxi route as the A320 and recovered. After completing relevant drills, the A320 returned and completed a landing with significant damage to the left main gear which was nevertheless locked down. The runway was vacated and passengers disembarked. The Investigation found that the cause of the problem was the cyclic fatigue of a pin linking the two parts of the left main gear torque link of manufacturing origin.
On 6 March 2018, smoke was detected coming from flight deck and passenger cabin air conditioning vents of an en-route Bombardier DHC8-400. A MAYDAY was declared to ATC but the prescribed response effectively cleared the smoke and no emergency evacuation on landing was deemed necessary. The Investigation found that the smoke was caused by oil leaking into the air conditioning system due to a failed right hand engine seal. The operator subsequently began to implement a recommended engine modification and adopt a system provided by the engine manufacturer to proactively detect such oil leaks before air conditioning systems are contaminated.
On 29 September 2017, the crew of an Airbus A320 detected a smell of burning plastic and simultaneously observed black smoke entering the flight deck near the right side rudder pedals. Completion of appropriate response procedures reduced the smoke and a diversion to Athens with a MAYDAY declared was without further event. The origin of the smoke and fumes was traced to the failure of the static inverter which was part of a batch which had been previously notified as faulty but not identified as such by the aircraft operator’s maintenance organisation which has since modified its relevant procedures.
On 8 October 2019, a BAe Jetstream 32 departing Münster/Osnabrück couldn’t be rotated and after beginning rejected takeoff from well above V1, the aircraft departed the side of the runway passing close to another aircraft at high speed before regaining the runway for the remainder of its deceleration. The Investigation noted that the flight was the first supervised line training sector for the very inexperienced First Officer but attributed the whole event to the Training Captain’s poor performance which had, apart many from other matters, led indirectly to the inability to rotate and to the subsequent directional control problem.
On 30 September 2017, an Airbus A380-800 en-route over Greenland suffered a sudden explosive uncontained failure of the number 4 engine shortly after thrust was increased to adjust the cruise level to FL 370. Following recovery of a crucial piece of ejected debris, the Investigation was able to determine that the failure was attributable to a specific type of fatigue failure within a titanium alloy used in the manufacture of the engine fan hub. This risk had not been identifiable during manufacture or in-service and had not been recognised by the engine manufacturer or during the engine certification process.
On 22 October 2012, the crew of a Eurocopter EC225 LP on a flight from Aberdeen to an offshore platform received an indication that the main gearbox (MGB) lubrication system had failed. Shortly after selecting the emergency lubrication system, that system also indicated failure and the crew responded in accordance with the QRH drill to “land immediately” by carrying out a successful controlled ditching. The ongoing investigation has found that there had been a mechanical failure within the MGB but that the emergency lubrication system had, contrary to indications, been functioning normally.
On 12 July 2013 an unoccupied and unpowered Boeing 787-8, remotely parked at London Heathrow after an arrival earlier the same day caught fire. An investigation found that the source of the fire was an uncontained thermal runaway in the lithium-metal battery within an Emergency Locator Transmitter (ELT). Fifteen Safety Recommendations, all but one to the FAA, were made as a result of the Investigation.
On 17 July 2007, the commander of a TAM Airlines Airbus A320 being operated with one thrust reverser locked out was unable to stop the aircraft leaving the landing runway at Congonhas at speed and it hit buildings and was destroyed by the impact and fire which followed killing all on board and others on the ground. The investigation attributed the accident to pilot failure to realise that the thrust lever of the engine with the locked out reverser was above idle, which by design then prevented both the deployment of ground spoilers and the activation of the pre-selected autobrake.
On 12 March 2009, a Sikorsky S-92A crew heading offshore from St. John's, Newfoundland declared an emergency and began a return after total loss of main gear box oil pressure but lost control during an attempted ditching. The Investigation found that all oil had been lost after two main gear box securing bolts had sheared. It was noted that ambiguity had contributed to crew misdiagnosis the cause and that the ditching had been mishandled. Sea States beyond the capability of Emergency Flotation Systems and the limited usefulness of personal Supplemental Breathing Systems in cold water were identified as Safety Issues.
Damage Tolerance
On 12 July 2013 an unoccupied and unpowered Boeing 787-8, remotely parked at London Heathrow after an arrival earlier the same day caught fire. An investigation found that the source of the fire was an uncontained thermal runaway in the lithium-metal battery within an Emergency Locator Transmitter (ELT). Fifteen Safety Recommendations, all but one to the FAA, were made as a result of the Investigation.
On 7 January 2013, a battery fire on a Japan Air Lines Boeing 787-8 began almost immediately after passengers and crew had left the aircraft after its arrival at Boston on a scheduled passenger flight from Tokyo Narita. The primary structure of the aircraft was undamaged. Investigation found that an internal short circuit within a cell of the APU lithium-ion battery had led to uncontained thermal runaway in the battery leading to the release of smoke and fire. The origin of the malfunction was attributed to system design deficiency and the failure of the type certification process to detect this.
On 26 September 2011, a Boeing 757-200 being operated by United Airlines on a scheduled passenger flight from Chicago to Denver experienced a left engine bird strike during deceleration after landing on runway 35R at destination in normal day visibility. The affected engine ran down as the aircraft cleared the runway and was shut down after a report of smoke being emitted from it. The aircraft was stopped and the remaining engine also shut down prior to a tow to the assigned terminal gate for passenger disembarkation. None of the 185 occupants were injured but the affected engine was severely damaged and there was visible evidence that some debris from it had impacted the aircraft fuselage.
On 10 November 2013 the left engine of a Fairchild SA227 on final approach suddenly ceased to produce any power at approximately 500 feet whilst continuing to operate. The crew did not identify what had happened in time to avoid losing control of the aircraft which then impacted terrain, caught fire and was destroyed. The Investigation found that premature failure of engine components had caused the engine malfunction and noted that some pilots may believe that the Negative Torque Sensing (NTS) System provided for the engines on this aircraft type will always detect high drag conditions arising from power loss.
On 24 October 2011, the crew of a Ryanair Boeing 737-800 operating the first flight after an unexpectedly severe overnight storm found that after take off, an extremely large amount of rudder trim was required to fly ahead. Following an uneventful return to land, previously undetected damage to the rudder assembly was found which was attributed to the effects of the storm. It was found that pre flight checks required at the time could not have detected the damage and noted that the wind speeds which occurred were much higher than those anticipated by the applicable certification requirements.
On 2 July 2013, a Korean Air Lines Boeing 777-300 experienced an uncommanded in-flight shutdown of one of its GE90-115B engines while crossing the Bering Sea. The crew made an uneventful diversion to Anadyr Russia. The Korean Aviation and Railway Accident Investigation Board (ARAIB) delegated investigative duties of this event to the National Transportation Safety Board (NTSB) which identified the cause of the failure as a manufacturing process deficiency which could affect nearly 200 similar engines.
On 16 January 2013, a main battery failure alert message accompanied by a burning smell in the flight deck was annunciated as an ANA Boeing 787-8 climbed through FL320 on a domestic flight. A diversion was immediately initiated and an emergency declared. A landing at Takamatsu was made 20 minutes later and an emergency evacuation completed. The Investigation found that the battery had been destroyed when thermal runway followed a suspected internal short circuit in one of the battery cells and concluded that certification had underestimated the potential consequences of such a single cell failure.
On 3 July 2010, an AW139 helicopter was climbing through 350 feet over Victoria Harbour Hong Kong just after takeoff when the tail rotor detached. A transition to autorotation was accomplished and a controlled ditching followed. All occupants were rescued but some sustained minor injuries. The failure was attributed entirely to manufacturing defects but no corrective manufacturer or regulatory action was taken until two similar accidents had occurred in Qatar (non-fatal) and Brazil (fatal) the following year and two interim Safety Recommendations were issued from this Investigation after which a comprehensive review of the manufacturing process led to numerous changes.
On 27 July 2006, a Bombardier CRJ200 being operated by Air Nostrum on a scheduled passenger flight from Barcelona to Basel, Switzerland in night VMC, suffered a sudden left hand engine failure and an associated engine fire when passing FL235 some 14 minutes after take off. An air turn back was made with indications of engine fire continuing until just three minutes before landing. An evacuation using the right hand exits was ordered by the Captain as soon as the aircraft had come to a stop and had been promptly actioned with the RFFS in attendance. There were no injuries to the 48 occupants during the evacuation and the only damage was to the affected engine.
On 1 April 2009, the flight crew of a Bond Helicopters Eurocopter AS332 L2 Super Puma en route from the Miller Offshore Platform to Aberdeen at an altitude of 2000 feet lost control of their helicopter when a sudden and catastrophic failure of the main rotor gearbox occurred and, within less than 20 seconds, the hub with the main rotor blades attached separated from the helicopter causing it to fall into the sea at a high vertical speed The impact destroyed the helicopter and all 16 occupants were killed. Seventeen Safety Recommendations were made as a result of the investigation.
Contributing ADD
On 5 March 2011, a Finnair Airbus A320 was westbound in the cruise in southern Swedish airspace after despatch with Engine 1 bleed air system inoperative when the Engine 2 bleed air system failed and an emergency descent was necessary. The Investigation found that the Engine 2 system had shut down due to overheating and that access to proactive and reactive procedures related to operations with only a single bleed air system available were deficient. The crew failure to make use of APU air to help sustain cabin pressurisation during flight completion was noted.
On 12 October 2018, the crew of a Boeing 737-400 already released to service under MEL conditions with an inoperative No 1 engine generator encountered a loss of services from the No 2 electrical system en-route to East Midlands which created a situation not addressed by QRH procedures. The flight was completed and both the new and existing defects were subsequently rectified relatively easily. The Investigation concluded that the operator involved appeared to be prioritising operational requirements over aircraft serviceability issues and made a range of Safety Recommendations aimed at improving company safety culture and the effectiveness of regulatory oversight.
On 29 April 2017, a Boeing 787-9 which had just reached cruise altitude after despatch with only one main ECS available began to lose cabin pressure. A precautionary descent and PAN was upgraded to a rapid descent and MAYDAY as cabin altitude rose above 10,000 feet. The Investigation found that aircraft release to service had not been preceded by a thorough enough validation of the likely reliability of the remaining ECS system. The inaudibility of the automated announcement accompanying the cabin oxygen mask drop and ongoing issues with the quality of CVR readout from 787 crash-protected recorders was also highlighted.
On 5 January 2014, an Airbus A380-800 en route to Singapore at night made an emergency descent and diversion to Baku after a loss of cabin pressure without further event. The Investigation attributed the pressure loss to a fatigue crack in a door skin which was initiated due to a design issue with door Cover Plates, which had not been detected when the Cover Plate was replaced with an improved one eighteen months earlier. Safety Issues related to cabin crew use of emergency oxygen and diversions to aerodromes with a fire category less than that normally required were also identified.
On 5 June 2015, a DHC8-200 descending towards Bradley experienced an in-flight fire which originated at a windshield terminal block. Attempts to extinguish the fire were unsuccessful with the electrical power still selected to the circuit. However, the fire eventually stopped and only smoke remained. An emergency evacuation was carried out after landing. The Investigation was unable to establish the way in which the malfunction that caused the fire arose but noted the continuing occurrence of similar events on the aircraft type and five Safety Recommendations were made to Bombardier to address the continuing risk.
On 17 November 2007 a Boeing 737-700 made an emergency descent after the air conditioning and pressurisation system failed in the climb out of Coolangatta at FL318 due to loss of all bleed air. A diversion to Brisbane followed. The Investigation found that the first bleed supply had failed at low speed on take off but that continued take off had been continued contrary to SOP. It was also found that the actions taken by the crew in response to the fault after completing the take off had also been also contrary to those prescribed.
On 9 June 1995 a de Havilland DHC-8-100 collided with terrain some 16 km east of Palmerston North aerodrome while carrying out a daytime instrument approach. The airplane departed Auckland as scheduled Ansett New Zealand flight 703 to Palmerston North airport.
On 7 July 2008, a Mc Donnell Douglas MD81 being operated by Midwest Airlines, Inc. had just taken off in day visual flight conditions when increasing pitch could initially not be controlled. Later, control was regained but with “higher than normal” pitch control pressure required to control the aircraft - after en-route diversion the aircraft landed uneventfully.
On 15 September 2006, an Easyjet Airbus A319, despatched under MEL provision with one engine generator inoperative and the corresponding electrical power supplied by the Auxiliary Power Unit generator, suffered a further en route electrical failure which included power loss to all COM radio equipment which could not then be re-instated. The flight was completed as flight planned using the remaining flight instruments with the one remaining transponder selected to the standard emergency code. The incident began near Nantes, France.
On 28 August 2002, an America West Airbus A320 operating under an ADD for an inoperative left engine thrust reverser veered off the side of the runway during the landing roll at Phoenix AZ after the Captain mismanaged the thrust levers and lost directional control as a consequence of applying asymmetric thrust. Substantial damage occurred to the aircraft but most occupants were uninjured.
Component Fault in Service
On 7 June 2021 an Embraer ERJ170 had just commenced its descent towards destination when both primary and secondary pitch trim systems failed resulting in excessive nose-down pitch control forces and an inoperative autopilot. The flight was completed without further event with the Pilot Flying using both hands on the control yoke to control pitch attitude manually. During the landing roll the nosewhweel steering system also failed. The pitch trim failure was attributed to probable jamming of the trim actuator due to water, possibly condensation, freezing within it. The steering system fault was attributed to a completely unrelated sensor failure.
On 16 March 2020, a PW150A-powered Bombardier DHC8-400 crew declared a PAN and turned back to Port Moresby after abnormal fumes and (much later) some visible ‘smoke’ which had become apparent after takeoff began to intensify causing some passengers breathing difficulties. Once clear of the landing runway, a precautionary rapid disembarkation was completed. The Investigation found that the source of the smoke/fumes was oil leaking from a failed right engine bearing seal. The failure was found to have occurred ahead of the recommended inspection interval for the seal concerned, a risk which engine manufacturer Pratt & Whitney Canada was aware of.
On 8 July 2019, a loud bang was heard following intermediate flap selection on a Boeing 747-400F making an approach to Harare and a concurrent uncommanded right roll was countered with left aileron. The flight was completed without further event but a post-flight inspection found part of the inboard section of the right wing flap assembly was missing and the right fuselage impact-damaged in several places. The missing flap section measuring 3.7 metres by 0.6 metres was recovered with detachment attributed to undetected fatigue cracking already present at component installation. A long history of problems with 747 flaps was noted.
On 18 March 2020, a Fokker 100 en-route to Port Moresby experienced a failure of the cabin pressurisation and air conditioning system due to a complete failure of the bleed air system. An emergency descent and a PAN were declared and a diversion to Madang completed. The Investigation noted unscheduled work on the bleed air system had occurred prior to the departure of the flight and that long running problems with this system had not been satisfactorily resolved until after the investigated occurrence when four malfunctioning components had finally been systematically identified and replaced.
On 18 April 2018, an engine fire warning was annunciated on an Airbus 330-300 which had just taken off from Atlanta. The warning remained after engine shutdown but was eventually replaced by a fire detection caution. Although not visible to the crew, a continued/reignited engine fire was subsequently seen by ATC on final approach and extinguished after landing. The Investigation concluded that the avoidable delay in the return to land had considerably increased the engine and pylon damage and noted that continuation of the fire had been facilitated by hydraulic fluid passing through a valve held partly open by debris.
On 2 July 2015, the left engine of a Bombarier CRJ 700A exiting the runway after landing at Denver caught fire and continued burning after the aircraft had been stopped on the taxiway and the engine shut down. The Investigation found that the fuel supply to the fuel-operated engine performance valve had failed and the quantity of fuel which then leaked had overwhelmed the engine cowl drain capacity and ignited. A history of similar failures was found and this one resulted in the introduction of additional mandatory in-serviced checks pending the replacement of the valve concerned with an improved design.
On 3 January 2019, a Boeing 737-500 en-route to Port Harcourt experienced signs of intermittent distress to an engine which subsequently failed during final approach there. After a mismanaged initial response before and after a go around, the failed engine was eventually shut down. After a delay of about 20 minutes, an attempted second approach was discontinued when it could not be stabilised. A third approach was then successfully completed. The engine was damaged beyond economic repair and the Investigation found that the operator had been aware of the intermittent malfunction of both engines over several months but ignored it.
On 15 December 2019, an Airbus A330-200 turned back to Sydney shortly after departure when a major hydraulic system leak was annunciated. The return was uneventful until engine shutdown after clearing the runway following which APU use for air conditioning was followed by a gradual build up of hydraulic haze and fumes which eventually prompted an emergency evacuation. The Investigation found that fluid leaking from ruptured rudder servo hose had entered the APU air intake. The resulting evacuation was found to have been somewhat disorganised with this being attributed mainly to a combination of inadequate cabin crew procedures and training.
On 5 August 2019, an Airbus A321 crew declared a MAYDAY immediately after clearing the landing runway at Valencia when a hold smoke warning was annunciated. An emergency evacuation was completed without injuries. This warning followed “white smoke” from the air conditioning system entering both the passenger cabin and flight deck in the four minutes before landing which had prompted the pilots to don oxygen masks. The Investigation found the white smoke was the direct consequence of an oil leak from the right engine as a result of the misalignment and breakage of a bearing and its associated hydraulic seal.
On 1 August 2019, an Airbus A320 annunciated an abnormal gear status indication when retraction was attempted after takeoff. Soon afterwards, an aircraft part was observed by an aircraft following the same taxi route as the A320 and recovered. After completing relevant drills, the A320 returned and completed a landing with significant damage to the left main gear which was nevertheless locked down. The runway was vacated and passengers disembarked. The Investigation found that the cause of the problem was the cyclic fatigue of a pin linking the two parts of the left main gear torque link of manufacturing origin.
Component Fault After Installation
On 31 December 2020, an Airbus A330-200 identified a fuel leak during a routine top-of-climb check but instead of following the prescribed engine shutdown and leak isolation procedure and then landing as soon as possible, the crew had continued on track until diverting to N’Djaména over 90 minutes later by which time nearly six tonnes of fuel was missing. The leak was caused by an incorrectly assembled connection at the pylon/engine interface. The flight crew’s significant procedural non-compliance was identified as having introduced an avoidable fire risk and been indicative of a systemically weak safety culture at the airline concerned.
On 1 March 2019, an Airbus A320 left engine suffered a contained failure soon after takeoff thrust was set for a night departure from London Stansted but despite the absence of an instruction to cabin crew to begin an evacuation, they did so anyway just before the aircraft was going to be taxied clear of the runway with the Captain only aware when passengers were seen outside the aircraft. The Investigation found that an evacuation had been ordered by the senior member of the cabin crew after she was “overwhelmed” by the situation and believed her team members were “scared”.
On 16 January 2010, an Iran Air Airbus A300-600 veered off the left side of the runway after a left engine failure at low speed whilst taking off at Stockholm. The directional control difficulty was attributed partly to the lack of differential braking but also disclosed wider issues about directional control following sudden asymmetry at low speeds. The Investigation concluded that deficiencies in the type certification process had contributed to the loss of directional control. It was concluded that the engine malfunction was due to the initiation of an engine stall by damage caused by debris from a deficient repair.
On 25 March 2008, an Air Atlanta Icelandic Boeing 747-300 was decelerating after landing at Dhaka when a fuel leak in the vicinity of the No 3 engine led to a fire which could not be extinguished. An emergency evacuation was accomplished with only a few minor injuries. The cause of the fuel leak was traced to mis-assembly of a fuel feed line coupling during a C Check some six months previously. The failure to follow clear AMM instructions for this task in two specific respects was of concern to the Investigating Agency.
On 23 July 2011, a Boeing 737-300 being operated by Jet2.com on a passenger flight from Leeds/Bradford to Paris CDG experienced violent vibration from the main landing gear at touch down in normal day visibility on runway 27R at a normal speed off a stabilised approach. This vibration was accompanied by lateral acceleration that made directional control difficult but the aircraft was kept on the runway and at a speed of 75 knots, the vibrations abruptly stopped. Once clear of the runway, the aircraft was stopped and the engines shutdown prior to a tow to the gate. None of the 133 occupants were injured.
On 15 March 2011, an ATR 72-200 on a non revenue positioning flight from Edinburgh to Paris CDG in night VMC with just the two pilots on board began to experience roll and directional control difficulties as the aircraft accelerated upon reaching the planned cruise altitude of FL230. A PAN call was made to ATC and a return to Edinburgh was made with successful containment of the malfunctioning flying controls.
On 27 March 2016 an ATR 42-500 had just departed Esbjerg when the right engine flamed out. It was decided to complete the planned short flight to Billund but on the night IMC approach there, the remaining engine malfunctioned and lost power. The approach was completed and the aircraft evacuated after landing. The Investigation found the left engine failed due to fuel starvation resulting from a faulty fuel quantity indication probably present since recent heavy maintenance and that the right engine had emitted flames during multiple compressor stalls to which it was vulnerable due to in-service deterioration and hot section damage.
On 8 March 2017, a Boeing MD83 departing Ypsilanti could not be rotated and the takeoff had to be rejected from above V1. The high speed overrun which followed substantially damaged the aircraft but evacuation was successful. The Investigation found that the right elevator had been locked in a trailing-edge-down position as a result of damage caused to the aircraft by high winds whilst it was parked unoccupied for two days prior to the takeoff. It was noted that on an aircraft with control tab initiated elevator movement, this condition was undetectable during prevailing pre flight system inspection or checks.
On 8 November 2017, an Avro RJ85 in cruise after just crossing into South African airspace from Zimbabwe suddenly experienced the apparently simultaneous failure of both left hand engines. After reviewing their situation, it was decided to continue to Johannesburg and this was achieved without further event. The Investigation found that the initiating failure was that of the number 2 (inner) engine which failed mechanically as a consequence of maintenance error but that this failure was uncontained and turbine debris from the number 2 hit the number 1 engine FADEC box and caused that engine to shut down too.
On 4 December 2014, directional control of an ATR 72-200 was compromised shortly after touchdown at Zurich after slightly misaligned nose wheels caused both tyres to be forced off their wheels leaving the wheel rims in direct contact with the runway surface. The Investigation found that the cause of the misalignment was the incorrect installation of a component several months earlier and the subsequent failure to identify the error. Previous examples of the same error were found and a Safety Recommendation was made that action to make the component involved less vulnerable to incorrect installation should be taken.
Pilot Verbal-only Defect Communication
On 27 July 2019, a fuel configuration advisory was annunciated on a Boeing 767-300 about to depart Auckland as a result of wing tank imbalance. Having established there was no evidence of a fuel leak, they planned to correct the imbalance in flight but then delayed this until it had exceeded the permitted limits. The fault was only verbally reported after flight and the aircraft continued to operate without centre tank use with maintenance remaining unaware of the fault for several days. The cause of imbalance was a fuel system fault subject to a crew response which was not followed.
Shortly after take-off from Jersey Airport, Channel Islands, a F27 experienced an uncontained engine failure and a major fire external to the engine nacelle. The fire was extinguished and the aircraft landed uneventfully back at Jersey.
On September 13 2008, at night and in good visual conditions*, a Boeing 737-500 operated by Aeroflot-Nord executed an unstabilised approach to Runway 21 at Bolshoye Savino Airport (Perm) which subsequently resulted in loss of control and terrain impact.
On 28 November 2004, a KLM B737-400 departed laterally from the runway on landing at Barcelona due to the effects on the nosewheel steering of a bird strike which had occured as the aircraft took off from Amsterdam.
On 12 January 2009, the flight crew of an Easyjet Boeing 737-700 on an airworthiness function flight out of Southend lost control of the aircraft during a planned system test. Controlled flight was only regained after an altitude loss of over 9000 ft, during which various exceedences of the AFM Flight Envelope occurred. The subsequent investigation found that the Aircraft Operators procedures for such flights were systemically flawed.
On 22 December 1999, a KAL Boeing 747 freighter crashed shortly after take-off from Stansted UK, following an ADI malfunction.
On 25 October 1999, a Learjet 35, being operated on a passenger charter flight by Sunjet Aviation, crashed in South Dakota following loss of control attributed to crew incapacitation.
Corrosion/Disbonding/Fatigue
On 16 March 2020, a PW150A-powered Bombardier DHC8-400 crew declared a PAN and turned back to Port Moresby after abnormal fumes and (much later) some visible ‘smoke’ which had become apparent after takeoff began to intensify causing some passengers breathing difficulties. Once clear of the landing runway, a precautionary rapid disembarkation was completed. The Investigation found that the source of the smoke/fumes was oil leaking from a failed right engine bearing seal. The failure was found to have occurred ahead of the recommended inspection interval for the seal concerned, a risk which engine manufacturer Pratt & Whitney Canada was aware of.
On 8 July 2019, a loud bang was heard following intermediate flap selection on a Boeing 747-400F making an approach to Harare and a concurrent uncommanded right roll was countered with left aileron. The flight was completed without further event but a post-flight inspection found part of the inboard section of the right wing flap assembly was missing and the right fuselage impact-damaged in several places. The missing flap section measuring 3.7 metres by 0.6 metres was recovered with detachment attributed to undetected fatigue cracking already present at component installation. A long history of problems with 747 flaps was noted.
On 2 July 2015, the left engine of a Bombarier CRJ 700A exiting the runway after landing at Denver caught fire and continued burning after the aircraft had been stopped on the taxiway and the engine shut down. The Investigation found that the fuel supply to the fuel-operated engine performance valve had failed and the quantity of fuel which then leaked had overwhelmed the engine cowl drain capacity and ignited. A history of similar failures was found and this one resulted in the introduction of additional mandatory in-serviced checks pending the replacement of the valve concerned with an improved design.
On 15 December 2019, an Airbus A330-200 turned back to Sydney shortly after departure when a major hydraulic system leak was annunciated. The return was uneventful until engine shutdown after clearing the runway following which APU use for air conditioning was followed by a gradual build up of hydraulic haze and fumes which eventually prompted an emergency evacuation. The Investigation found that fluid leaking from ruptured rudder servo hose had entered the APU air intake. The resulting evacuation was found to have been somewhat disorganised with this being attributed mainly to a combination of inadequate cabin crew procedures and training.
On 5 August 2019, an Airbus A321 crew declared a MAYDAY immediately after clearing the landing runway at Valencia when a hold smoke warning was annunciated. An emergency evacuation was completed without injuries. This warning followed “white smoke” from the air conditioning system entering both the passenger cabin and flight deck in the four minutes before landing which had prompted the pilots to don oxygen masks. The Investigation found the white smoke was the direct consequence of an oil leak from the right engine as a result of the misalignment and breakage of a bearing and its associated hydraulic seal.
On 1 August 2019, an Airbus A320 annunciated an abnormal gear status indication when retraction was attempted after takeoff. Soon afterwards, an aircraft part was observed by an aircraft following the same taxi route as the A320 and recovered. After completing relevant drills, the A320 returned and completed a landing with significant damage to the left main gear which was nevertheless locked down. The runway was vacated and passengers disembarked. The Investigation found that the cause of the problem was the cyclic fatigue of a pin linking the two parts of the left main gear torque link of manufacturing origin.
On 20 February 2021, a PW4077-powered Boeing 777-200 was climbing through 12,500 feet after takeoff from Denver when there was a sudden uncontained failure of the right engine. The associated fire did not fully extinguish in response to the prescribed non-normal procedure and on completion of a return to land, it was fully extinguished before the aircraft could be towed in for passenger disembarkation. The Investigation has already established that the failure originated in a single fan blade within which internal fatigue cracking had been initiated. All operators of 777s powered by PW4000 series engines have grounded their fleets indefinitely.
On 23 February 2020, a Bombardier Challenger 605 making a flapless landing after a system failure during descent briefly lost control when reverse thrust selection after a normal touchdown was followed by the aircraft becoming airborne before stick push activation was followed by a hard second touchdown. Structural and abrasion fuselage damage was caused. The Investigation attributed the flap failure to corrosion within the specified maintenance inspection interval and the brief loss of control during landing to a combination of inadequate crew preparation for the landing and the fact that simulator replication of aircraft handling did not correspond to reality.
On 31 December 2017, a de Havilland DHC2 floatplane being manoeuvred at low level over Jerusalem Bay shortly after takeoff was observed to enter a steeply banked turn from which it appeared to depart controlled flight and impact the water surface below almost vertically. The Investigation concluded that the aircraft had stalled despite the exemplary proficiency record of the pilot and that in the absence of any other plausible explanation found that the loss of control was likely to have been the effect of an elevated exposure to carbon monoxide found during post mortem toxicology testing.
On 11 November 2019, one of the two PW100 series engines of a Bombardier DHC8-300 failed catastrophically when takeoff power was set prior to brake release. The Investigation found that the power turbine shaft had fractured in two places and all first and second stage power turbine blades had separated from their disks. The shaft failure was found to have been caused by fatigue cracking initiated by corrosion pitting which was assessed as probably the result of prolonged marine low-altitude operations by the aircraft. It was found that this fatigue cracking could increase undetected during service between scheduled inspections.
Cross Connection
On 17 October 2019, a Saab 2000 overran the Unalaska runway after touchdown following difficulty braking and exited the airport perimeter before finally coming to rest on shoreline rocks. The Investigation attributed the poor braking to incorrect brake system wiring originating during maintenance some 2½ years earlier but noted the touchdown occurred with crew awareness that the prevailing tailwind component was well in excess of the permitted limits with no reason not to use the into-wind runway and attributed this to plan continuation bias. The aircraft operator’s failure to apply their specifically-applicable airport qualification requirements to the Captain was noted.
On 11 November 2018, an Embraer 190-100LR just airborne on a post maintenance non revenue positioning flight became extremely difficult to control as it entered cloud despite the complete absence of any flight control warnings. After reversion to Direct Law, partial normal control was regained and, once visual, the flight was guided to an eventually successful landing. The Investigation found that the aircraft had been released from heavy maintenance with the aileron system incorrectly configured and attributed this primarily to the comprehensively dysfunctional working processes at the maintenance facility involved. Extensive airframe deformation meant the aircraft was a hull loss.
On 13 August 2012, an Ilyushin IL76 freighter overran landing runway 11 at St John's at 40 knots. The Investigation established that although a stabilised approach had been flown, the aircraft had been allowed to float in the presence of a significant tail wind component and had not finally touched down until half way along the 2590 metre long runway. It was also found that reverse thrust had then not been fully utilised and that cross connection of the brake lines had meant that the anti skid pressure release system worked in reverse sense, thus reducing braking effectiveness.
On 21 March 2001 an Airbus A320-200, operated by Lufthansa, experienced a flight controls malfunctions shortly after take-off which resulted in loss of control and subsequent near terrain impact. The uncontrolled roll, due to the malfunction of the pilot flying's sidestick, was recovered by the other pilot and the aircraft safely returned to land in Frankfurt without further incident.
Engine Compressor Washing
On 28 February 2019, an Embraer E195 abandoned takeoff from Exeter when fight deck fumes/smoke accompanied thrust applied against the brakes. When informed of similar conditions in the cabin, the Captain ordered an emergency evacuation. Some passengers using the overwing exits re-entered the cabin after becoming confused as to how to leave the wing. The Investigation attributed the fumes to an incorrectly-performed engine compressor wash arising in a context of poorly-managed maintenance and concluded that guidance on overwing exit use had been inadequate and that the 1.8 metre certification height limit for exits without evacuation slides should be reduced.
On 3 October 2015, an Airbus A320 which had just taken off from Dublin experienced fumes from the air conditioning system in both flight deck and cabin. A 'PAN' was declared and the aircraft returned with both pilots making precautionary use of their oxygen masks. The Investigation found that routine engine pressure washes carried out prior to departure have been incorrectly performed and a contaminant was introduced into the bleed air supply to the air conditioning system as a result. The context for the error was found to be the absence of any engine wash procedure training for the Operator's engineers.
On 9 September 2012, the crew of a DHC8-300 climbing out of Abu Dhabi declared a PAN and returned after visual evidence of the right engine overheating were seen from the passenger cabin. The Investigation found that the observed signs of engine distress were due to hot gas exiting through the cavity left by non-replacement of one of the two sets of igniters on the engine after a pressure wash carried out overnight prior to the flight and that the left engine was similarly affected. The context for the error was identified as a dysfunctional maintenance organisation at the Operator.
On 5 July 2006, during daytime, a Boeing 737-500, operated by Air Nippon Co., Ltd. took off from Fukuoka Airport as All Nippon Airways scheduled flight 2142. At about 08:10, while flying at 37,000 ft approximately 60 nm southeast of Kushimoto VORTAC, a cabin depressurization warning was displayed and the oxygen masks in the cabin were automatically deployed. The aircraft made an emergency descent and, at 09:09, landed on Chubu International Airport.
Ejected Engine Failure Debris
On 20 February 2021, a PW4077-powered Boeing 777-200 was climbing through 12,500 feet after takeoff from Denver when there was a sudden uncontained failure of the right engine. The associated fire did not fully extinguish in response to the prescribed non-normal procedure and on completion of a return to land, it was fully extinguished before the aircraft could be towed in for passenger disembarkation. The Investigation has already established that the failure originated in a single fan blade within which internal fatigue cracking had been initiated. All operators of 777s powered by PW4000 series engines have grounded their fleets indefinitely.
On 11 November 2019, one of the two PW100 series engines of a Bombardier DHC8-300 failed catastrophically when takeoff power was set prior to brake release. The Investigation found that the power turbine shaft had fractured in two places and all first and second stage power turbine blades had separated from their disks. The shaft failure was found to have been caused by fatigue cracking initiated by corrosion pitting which was assessed as probably the result of prolonged marine low-altitude operations by the aircraft. It was found that this fatigue cracking could increase undetected during service between scheduled inspections.
On 27 August 2016, debris from sudden uncontained failure of the left CFM56-7B engine of a Boeing 737-700 climbing through approximately FL 310 west southwest of Pensacola in day VMC penetrated the fuselage barrel and caused a rapid depressurisation. An emergency descent and a diversion to Pensacola followed without further event. The Investigation found that collateral damage had followed low-cycle fatigue cracking of a single fan blade due to a previously unrecognised weakness in the design of this on-condition component which, because it had not been detected during the engine certification process, meant its consequences “could not have been predicted”.
On 30 September 2017, an Airbus A380-800 en-route over Greenland suffered a sudden explosive uncontained failure of the number 4 engine shortly after thrust was increased to adjust the cruise level to FL 370. Following recovery of a crucial piece of ejected debris, the Investigation was able to determine that the failure was attributable to a specific type of fatigue failure within a titanium alloy used in the manufacture of the engine fan hub. This risk had not been identifiable during manufacture or in-service and had not been recognised by the engine manufacturer or during the engine certification process.
On 28 May 2012 a GE90-powered Air Canada Boeing 777-300ER experienced sudden failure of the right engine during the initial climb after take off. There were no indications of associated engine fire and the failed engine was secured, fuel jettisoned and a return to land made. The Investigation found that the failure was related to a known manufacturing defect which was being controlled by repetitive boroscope inspections, the most recent of which was suspected not to have identified deterioration in the affected part of the engine.
On 7 June 2016, a GE90-115B engined Boeing 777-300 made a high speed rejected takeoff on 3200 metre-long runway 14 at Dhaka after right engine failure was annunciated at 149KCAS - just below V1. Neither crew nor ATC requested a runway inspection and 12 further aircraft movements occurred before it was closed for inspection and recovery of 14 kg of debris. The Investigation found that engine failure had followed Super Absorbent Polymer (SAP) contamination of some of the fuel nozzle valves which caused them to malfunction leading to Low Pressure Turbine (LPT) mechanical damage. The contaminant origin was not identified.
On 8 November 2017, an Avro RJ85 in cruise after just crossing into South African airspace from Zimbabwe suddenly experienced the apparently simultaneous failure of both left hand engines. After reviewing their situation, it was decided to continue to Johannesburg and this was achieved without further event. The Investigation found that the initiating failure was that of the number 2 (inner) engine which failed mechanically as a consequence of maintenance error but that this failure was uncontained and turbine debris from the number 2 hit the number 1 engine FADEC box and caused that engine to shut down too.
On 17 April 2018, sudden uncontained left engine failure occurred to a CFM56-7B powered Boeing 737-700 when climbing through approximately FL320. Consequent damage included a broken cabin window causing rapid decompression and a passenger fatality. Diversion to Philadelphia without further significant event then followed. A single fan blade was found to have failed due to undetected fatigue. The Investigation noted that the full consequences of blade failure had not been identified during engine / airframe type certification nor fully recognised during investigation of an identical blade failure event in 2016 which had occurred to another of the same operator s 737-700s.
On 27 May 2016, a Boeing 777-300 crew made a high speed rejected take off when departing from Tokyo after a number one engine failure warning was quickly followed by a fire warning for the same engine and ATC advice of fire visible. As the fire warning continued with the aircraft stopped, an emergency evacuation was ordered. The Investigation found that the engine failure and fire had occurred when the 1st stage disc of the High Pressure Turbine had suddenly failed as result of undetected fatigue cracking which had propagated from an undetected disc manufacturing fault.
On 15 October 2015 a Boeing 747-300 experienced significant vibration from one of the engines almost immediately after take-off from Tehran Mehrabad. After the climb out was continued without reducing the affected engine thrust an uncontained failure followed 3 minutes later. The ejected debris caused the almost simultaneous failure of the No 4 engine, loss of multiple hydraulic systems and all the fuel from one wing tank. The Investigation attributed the vibration to the Operator's continued use of the engine without relevant Airworthiness Directive action and the subsequent failure to continued operation of the engine after its onset.
Dispatch of Unserviceable Aircraft
On 26 February 2020, after a difficult Airbus A321 left engine first flight of the day start, the same happened on the third sector with en-route engine abnormalities then affecting both engines. With no fault found during post flight maintenance inspections and despite similar engine starting problems, both engines then malfunctioned after takeoff from Gatwick. A MAYDAY return followed. Investigation found that the cause was fuel system contamination by addition of approximately 38 times the correct quantity of biocide during earlier scheduled maintenance and that the release of the aircraft to service for the flight had followed inadequate troubleshooting action.
On 13 April 2013, an Air France Airbus A330-200 was damaged during a hard (2.74 G) landing at Caracas after the aircraft commander continued despite the aircraft becoming unstabilised below 500 feet agl with an EGPWS ‘SINK RATE’ activation beginning in the flare. Following a superficial inspection, maintenance personnel determined that no action was required and released the aircraft to service. After take off, it was impossible to retract the landing gear and the aircraft returned. Considerable damage from the earlier landing was then found to both fuselage and landing gear which had rendered the aircraft unfit to fly.
On 27 February 2001, a Loganair SD3-60 lost all power on both engines soon after take off from Edinburgh. An attempt to ditch in the Firth or Forth in rough seas resulted in the break up and sinking of the aircraft and neither pilot survived. The loss of power was attributed to the release of previously accumulated frozen deposits into the engine core when the engine anti icing systems were selected on whilst climbing through 2200 feet. These frozen deposits were considered to have accumulated whilst the aircraft had been parked prior to flight without engine intake blanks fitted.
On 12 October 2018, the crew of a Boeing 737-400 already released to service under MEL conditions with an inoperative No 1 engine generator encountered a loss of services from the No 2 electrical system en-route to East Midlands which created a situation not addressed by QRH procedures. The flight was completed and both the new and existing defects were subsequently rectified relatively easily. The Investigation concluded that the operator involved appeared to be prioritising operational requirements over aircraft serviceability issues and made a range of Safety Recommendations aimed at improving company safety culture and the effectiveness of regulatory oversight.
On 11 November 2018, an Embraer 190-100LR just airborne on a post maintenance non revenue positioning flight became extremely difficult to control as it entered cloud despite the complete absence of any flight control warnings. After reversion to Direct Law, partial normal control was regained and, once visual, the flight was guided to an eventually successful landing. The Investigation found that the aircraft had been released from heavy maintenance with the aileron system incorrectly configured and attributed this primarily to the comprehensively dysfunctional working processes at the maintenance facility involved. Extensive airframe deformation meant the aircraft was a hull loss.
On 16 July 2016, an Airbus A321’s unstabilised approach at Fuerteventura during pilot line training was not discontinued and takeover of control and commencement of a go-around had occurred just before a very hard runway contact. The subsequent landing was successful but serious damage to the main landing gear was not rectified before the next flight. The Investigation found that the hard touchdown had been recorded as in excess of 3.3g and that the return flight had been “risky and unsafe” after failure of the Captain and maintenance personnel at the Operator to recognise the seriousness of the hard landing.
On 6 April 2016, a BAe ATP partly left the side of the runway soon after touchdown, regaining it after 155 metres before completing its landing roll. It sustained damage rendering it unfit to continue flying but this was not noticed until five further flights had been made. Investigation attributed the excursion to lack of pilot response to unexpected beta range power and the continued flying to the aircraft Captain's failure to ensure proper event recording, accurate operator notification or a post-excursion engineering inspection of the aircraft. Systemic inadequacy in safety management and culture at the operator was identified.
On 27 November 2010, collateral damage to the wing of an IL-76 in the vicinity of an uncontained engine failure, which occurred soon after take-off from Karachi, led to fuel in that wing igniting. Descent from a maximum height of 600 feet occurred accompanied by a steadily increasing right bank. Just under a minute after take-off ground impact occurred and impact forces and fire destroyed the aircraft. The Investigation concluded that the engine failure was attributable to component fatigue in the LP compressor and that it would have been impossible for the crew to retain control.
On 20 February 2014, an ATR 72-600 crew mishandled their response to an intended airspeed adjustment whilst using VS mode during descent to Sydney and an upset involving opposite control inputs from the pilots caused an elevator disconnect. The senior cabin attendant sustained serious injury. After recovery of control, the flight was completed without further event. Post flight inspection did not discover damage to the aircraft which exceeded limit and ultimate loads on the stabilisers and the aircraft remained in service for a further five days until it was grounded for replacement of both horizontal and vertical stabilisers.
Maintenance FOD
On 22 September 2021, a Boeing 787-9 was found on arrival at its destination, Los Angeles, to have completed the 14½ hour flight from Melbourne with all four fan cowl static ports taped over. The crew had not observed any adverse consequence. The Investigation attributed the oversight to inadequate pre-flight maintenance and operational procedures and found that failure to identify the taping had resulted in the aircraft departing with reduced redundancy to the engine electronic control systems of both engines.
On 23 October 2020, an Airbus A320 taking off from Brisbane became difficult to keep on the centreline as speed increased and takeoff was rejected from a low speed. It remained on the runway and messages indicating a malfunctioning right engine were then seen. The Investigation found that one engine had surged as thrust was applied due to damage caused by a screwdriver tip inadvertently left in the engine during routine maintenance and that the pilot flying had used the rudder when attempting to maintain directional control during the reject despite its known ineffectiveness for this purpose at low speeds.
On 7 December 2016, the crew of an ATR 42-500 lost control after airworthiness-related complications followed shutdown of the left engine whilst in the cruise and high speed terrain impact followed. The Investigation concluded that three pre-existing faults with the left engine and its propeller control mechanism had led to a loss of power which had necessitated its shutdown but that these faults had then caused much higher left side drag than would normally result from an engine shutdown and made it progressively more difficult to maintain control. Recovery from a first loss of control was followed by another without recovery.
On 27 October 2017, an Airbus A320 returned to Auckland after advice from ATC that the right engine may have been affected by ingestion of FOD during engine start - a clipboard and paper left just inside the right hand engine by an employee of the airline’s ground handling contractor acting as the aircraft loading supervisor. The subsequent inspection found paper throughout the engine and minor damage to an engine fan blade and the fan case attrition liner. The Dispatcher overseeing the departure said she had seen the clipboard inside the engine but assumed it would be retrieved before departure.
On 11 February 2017, a Cessna 402 failed to stop on the runway when landing at Virgin Gorda and was extensively damaged. The Investigation noted that the landing distance required was very close to that available with no safety margin so that although touchdown was normal, when the brakes failed to function properly, there was no possibility of safely rejecting the landing or stopping normally on the runway. Debris in the brake fluid was identified as causing brake system failure. The context was considered as the Operator s inadequate maintenance practices and a likely similar deficiency in operational procedures and processes.
In flight separation of failed component
On 8 July 2019, a loud bang was heard following intermediate flap selection on a Boeing 747-400F making an approach to Harare and a concurrent uncommanded right roll was countered with left aileron. The flight was completed without further event but a post-flight inspection found part of the inboard section of the right wing flap assembly was missing and the right fuselage impact-damaged in several places. The missing flap section measuring 3.7 metres by 0.6 metres was recovered with detachment attributed to undetected fatigue cracking already present at component installation. A long history of problems with 747 flaps was noted.
On 1 August 2019, an Airbus A320 annunciated an abnormal gear status indication when retraction was attempted after takeoff. Soon afterwards, an aircraft part was observed by an aircraft following the same taxi route as the A320 and recovered. After completing relevant drills, the A320 returned and completed a landing with significant damage to the left main gear which was nevertheless locked down. The runway was vacated and passengers disembarked. The Investigation found that the cause of the problem was the cyclic fatigue of a pin linking the two parts of the left main gear torque link of manufacturing origin.
On 25 March 2018, an ATR 42-500 main landing gear bay door weighing 15 kg detached shortly after a night descent had begun but this was unknown until the flight arrived at Aurillac. The Investigation found that the root cause of the detachment was a loose securing nut which had triggered a sequence of secondary failures within a single flight which culminated in the release of the door. It was concluded that the event highlighted specific and systemic weakness in relevant airworthiness documentation and practice in relation to the lost door and the use of fasteners on this aircraft type generally.
On 14 August 2018, an Airbus A320 departed Perth without full removal of its main landing gear ground locks and the unsecured components fell unseen from the aircraft during taxi and takeoff, only being recovered after runway FOD reports. The Investigation identified multiple contributory factors including an inadequately-overseen recent transfer of despatch responsibilities, the absence of adequate ground lock use procedures, the absence of required metal lanyards linking the locking components not attached directly to each gear leg flag (as also found on other company aircraft) and pilot failure to confirm that all components were in the flight deck stowage.
On 17 March 2017, uncommanded engine indications on a Saab 340B en route to Sydney were followed by vibration of the right engine after which, as the crew commenced right engine shutdown, its propeller assembly separated from the engine. A PAN was declared and the flight subsequently reached Sydney without further event. The Investigation found that the propeller gearbox shaft had fractured because of undetected internal fatigue cracking in the shaft. Applicable in-service shaft inspection procedures were found to be inadequate and mandatory enhancements to these procedures have since been introduced.
On 23 September 2017, a large wing-to-body fairing panel confirmed to have dropped from a Boeing 777-200 passing over the centre of Osaka after takeoff off from Kansai hit and significantly damaged a moving vehicle. The Investigation found that the panel involved had a sufficient history of attachment bracket failures for Boeing to have developed an improved thicker bracket for new-build aircraft which had then been advised as available as a replacement for in-service 777-200 aircraft in a Service Letter which KLM had decided not to follow. Although some incorrect bracket attachment bolts were found, this was not considered contributory.
On 4 December 2014, directional control of an ATR 72-200 was compromised shortly after touchdown at Zurich after slightly misaligned nose wheels caused both tyres to be forced off their wheels leaving the wheel rims in direct contact with the runway surface. The Investigation found that the cause of the misalignment was the incorrect installation of a component several months earlier and the subsequent failure to identify the error. Previous examples of the same error were found and a Safety Recommendation was made that action to make the component involved less vulnerable to incorrect installation should be taken.
On 16 October 2015, the unlatched fan cowl doors of the left engine on an A320 fell from the aircraft during and soon after takeoff. The one which remained on the runway was not recovered for nearly an hour afterwards despite ATC awareness of engine panel loss during takeoff and as the runway remained in use, by the time it was recovered it had been reduced to small pieces. The Investigation attributed the failure to latch the cowls shut to line maintenance and the failure to detect the condition to inadequate inspection by both maintenance personnel and flight crew.
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