Description

On 12 May 2010, an Airbus A330-200 (5A-ONG) being operated by Libyan airline Afriqiyah Airways on a scheduled passenger flight from Johannesburg to Tripoli as BU771 with a cruise relief First Officer on board and observing in the flight deck for the approach, commenced a go around in day Instrument Meteorological Conditions (IMC) after failing to obtain the required visual reference to land following a non precision approach to runway 09. However, soon afterwards, it crashed short of the intended landing runway just outside the aerodrome perimeter and was destroyed by the impact and subsequent fire with all but one of the 104 occupants being killed.

Investigation

An Investigation was carried out by the Libyan Civil Aviation Authority. Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) data was successfully downloaded from the recovered recorders. It was noted that both pilots and the observing relief First Officer had recorded exactly the same A330 flying hours total of 516 since qualifying on type at the manufacturer’s training facility the previous year and had all been previously rated on the Airbus A320.

The impact site was located 1200 metres from the threshold of the runway to which the approach had been made and 150 metres to the right of its extended centreline just outside the airport perimeter - see the diagram below taken from the Official Report. It was noted that the time of sunrise was ten minutes after the accident occurred, a time of day and year when fog and / or low Stratus cloud was not unusual, although not forecast on the day of the accident.

It was established that the First Officer had been PF and had flown a L/DME approach - see the chart below. Prior to commencement of this approach, the surface weather report had been given as ‘visibility 6km, sky clear’ and the applicable TAF was showing a ‘PROB 40’ of 5000 metres visibility in mist. Whilst the aircraft was on the approach and below 1200 ft Altimeter Pressure Settings, an aircraft which had just landed advised of fog patches beginning to form on the approach. As the aircraft passed 1000 feet QNH, the crew confirmed to ATC that they would report the runway in sight to obtain landing clearance.

With no response by the Captain to the automatic annunciation ‘MINMUM’ as the applicable MDA of 620 feet QNH (410 feet agl) was passed, the PF had then asked the Captain if the approach should be abandoned and followed this with a repeat of the automatic ‘THREE HUNDRED’ computer callout which had, by then, just occurred, the GPWS/TAWS “TOO LOW TERRAIN” alert activated and this appeared to have prompted the Captain to call a go around. This call was acknowledged and the go around initiated by the PF from 490 feet QNH (280 feet agl) with AP disconnection, Take-off / Go-around (TO/GA) Mode selection, and landing gear retracted.

Although the go around was initiated promptly and positively by the PF, only four seconds later, he had begun to apply nose-down inputs on his side stick, resulting in a decrease in the pitch attitude of the aircraft until it became negative. The maximum altitude reached was only 670 feet QNH (450 feet agl). It was considered that these continued inputs had been “consistent with the high pitch attitude he could have perceived (and) typical of a somatogravic perceptual illusion occurring in the absence of outside visual references and (a failure to monitor) the artificial horizon”. It was noted that the PF “would have maintained nose-down inputs as long as he was feeling this effect, the pitch attitude perceived being relatively constant and greater than the theoretical pitch attitude during a go-around”. See: Appendix 6: Study of Spatial Disorientation.

It was surmised that the PFs successive callouts of ‘Flaps’ at this point may well have been “due to his detection of the red and black stripe on the speed tape and the very high speed trend due to acceleration”. It was further considered that this apparent ‘tunnel vision’ of the speed trend at the expense of the more central indication of the increasingly unfavourable aircraft attitude was indicative of a desire to avoid replicating what had happened during a go around from an unstable approach to the same runway with the same crew two weeks earlier during which the over speed warning had been was activated. This event had been identified by the Operator OFDM system but no follow up action had been taken by the time of the accident approach.

As the aircraft had begun to descend from 450 ft agl, it was noted that “neither crew member seemed to be aware of the flight path of the aircraft”. The Captain had responded to the PFs ‘Flaps’ calls and spoken to TWR but was not monitoring the flight path. As the aircraft descended again through the MDA equivalent 410 feet agl and the automatic ‘MINMIMUM’ Call activated again, there was no recorded response from either pilot.

It was found from FDR data that, from the point of go around onwards, the Captain had begun making small inputs to his side stick, but these had not been sufficient to trigger the ‘Dual Input’ Alert. It was considered that the available evidence indicated that, “like the PF, the Captain’s attention appeared to be focused on the speed tape”. He had called ‘Speed’ and had pulled the Speed/Mach button on the FCU to select the current speed at 176 KCAS when the speed trend was still mainly in the red band. It was considered possible that the Captain also wanted to avoid triggering the over speed warning with a similar recollection of the earlier approach.

Finally, “three seconds after having selected the speed on the FCU and during the seven seconds before the aircraft struck the ground, a succession of TAWS alerts and warnings of increasing severity was recorded. In response to the first of these, the Captain had applied a sharp nose-down input followed immediately by a contrary pitch-up input by the First Officer. The Captain maintained his nose-down input on the side stick whilst taking side stick priority so that the effect of First Officer’s side stick selection to the pitch-up stop was negated.

At about 180 feet agl, less than two seconds before impact and one second after the last GPWS/TAWS ‘PULL UP’ warning was triggered, the Captain had applied a pitch-up input to the stop and released the priority side stick push button with the First Officer’s side stick input also to the pitch-up stop. It was considered that these inputs probably indicated that the two operating crew members had finally become aware of the aircraft path and ground proximity. However, it was seen from the data that the Captain had reversed his pitch-up input to a pitch-down input one second before impact.

In respect of the flight crew performance, it was noted that the approach brief given had been minimal and selective. Initially, although there was some evidence of non standard flight management with the AP engaged, exchanges between the two pilots “suggest that at this stage of the flight, both crew members shared the same approach strategy”. Thereafter, although the PF was clearly focused on his task, Crew Resource Management was not very effective and it was considered that in the latter part of the approach, “the pilots no longer seemed to share the same strategy for conducting the final approach” and that meaningful CRM had effectively ceased as soon as the go around had been initiated.

The vertical profile shown below was included as Appendix 11 to the Report and is based on consolidated data from the FDR and CVR summarises the approach and go around sequence leading up to impact. The third illustration, Appendix 10 to the Official Report, shows selected FDR parameters for the go around and adds a modelled representation of perceived pitch due to the effects of somatogravic illusion for comparison with actual pitch.

It was noted that the lack of any follow up after the unstable approach to the same runway flown by the same crew on the same aircraft two weeks earlier had removed a potentially significant opportunity for the both pilots to recognise the potential issues associated with managing non-precision approaches and the transition to any go around from one.

It was accepted that the performance of both pilots may have been impaired by fatigue but the available evidence did not allow this possibility to be confirmed or eliminated. See Appendix 7: Study of Fatigue.

It was considered that whilst the go around could have been performed with the AP remaining engaged, the First Officer’s choice of manual control “may be explained as a response to an emergency” as if a TAWS ‘PULL UP’ warning rather than the ‘TOO LOW TERRAIN’ alert which had actually occurred.

Overall, it was concluded that evidence led to a conclusion that the go around had been attempted without the Captain having fully engaged with the change from his previous expectation of a landing.

The question of inaccurate surface weather reports and broadcasts was considered. It was clear that, in respect of the prevailing visibility as the accident aircraft approached, evidence from the crew of the aircraft which landed just before the crash and another that was allowed (despite the degraded fire cover) to take off just after it was that the real cloud cover and visibility were not being reported by Meteorological Terminal Air Report (METAR) / Automatic Terminal Information Service (ATIS).

The pilot of the aircraft ahead of the accident aircraft on approach that landed on runway 09 four minutes before the accident and had advised on frequency of “fog patches beginning to form” advised the Investigation that although when he initiated the final descent, he could see the airport and the runway lights through the mist, he had “then passed through a more or less dense cloud layer that he considered to be low stratus cloud. Close to the minimum descent altitude, he regained sight of the ground and landed”. He had also suggested to ATC once parked that the runway in use should be changed and when he had heard the missed approach call, had thought this manoeuvre was due to his message about the weather conditions.

The departing aircraft crew reported that when they left their hotel in town at 0240Z, the tops of taller buildings were already invisible due to low cloud. Once on board their aircraft, they found that the ATIS being broadcast was timed at 2130Z the previous day. Then, when cleared to taxi for a 09 departure at about 0350Z, they again noticed that weather conditions were different from those being reported on the ATIS and estimated the cloud ceiling to be lower than reported and the visibility to be 2000-3000 metres. Shortly afterwards, they reported having heard the accident aircraft declare a go around and subsequently saw it “appearing below the clouds, in a low-nose attitude and almost wings level” before it impacted the ground.

In respect of the deteriorating weather conditions for approaches to runway 09 and the potential for a change to runway27, a recorded telephone exchange between the TWR and Tripoli ACC controllers had begun at 03:55:47Z with the Tripoli ACC controller answering a call from the Tripoli TWR controller on the direct line after 45 seconds of calling and three minutes prior to the transfer of the accident aircraft to the TWR. ACC was asked about a runway change from 09 to 27 and replied that this was impossible because there were six or seven flights in sequence. The TWR controller informed the ACC controller that wind was 240/10 Knots and tried to convince ACC to change the runway but could not and the final answer from the ACC was that there is no way to change the active runway adding the nearest traffic was 10 miles away. The call was ended by the ACC Controller saying that he was busy and would call TWR later.

It was concluded that the Cause of the Accident was:

• The lack of common action plan during the approach and a final approach continued below the MDA, without ground visual reference acquired.
• The inappropriate application of flight control inputs during a go- around and on the activation of TAWS warnings,
• The lack of monitoring and controlling of the flight path.

It was considered that these events could be explained by the following:

• Limited CRM on approach that degraded during the missed approach. This degradation was probably amplified by numerous radio-communications during the final approach and the crew’s state of fatigue
• Aircraft control inputs typical in the occurrence of somatogravic perceptual illusions.
• Inappropriate systematic analysis of flight data and feedback mechanism within the AFRIQIYAH Airways
• Non adherence to the company operation manual, SOPs and standard terminology

The Investigation Committee also identified the following as Contributory Factors to the accident:

• The weather available to the crew did not reflect the actual weather situation in the final approach segment at Tripoli International Airport.
• The inadequacy of training received by the crew.
• Shared use of the Tower frequency by both air and ground movements control.

A total of 21 Safety Recommendations were made as a result of the Investigation:

• that Flight Crews (should be) required to comply with company operations manual in regard to reportable events regardless of the Crew member position.

• that Flight Crews should strictly adhere to Company SOPs.

• that all Airlines must to comply with the current regulation related to operation of a flight (data) analysis programme and create an environment of safety awareness.

• that Aircraft Maintenance Personnel must not perform any maintenance work unless it is covered by the (aircraft) manufacturer’s documents and subsequent consultation with the manufacturer is recommended.

• that Air Traffic Control personnel have to comply with the national and international standard in performing their duties as well as to stick with the standard phraseology used in the field.

• that Air Traffic Control personnel should take due care about runway selection taking in consideration wind speed, direction and runway facilities as (the) main factors.

• that the Libyan Civil Aviation Authority Air Navigation Department should distinguish the ground and the air as will as approach and area movements communication knowing that facilities are available.

• that the Airports Authority should upgrade runway 09 at Tripoli International Airport to be equipped with precision approach facilities.

• that the Libyan Civil Aviation Authority and the National Safety Board should make available and use of radio communications facilities between (the) airport tower and fire fighting trucks.

• that Airbus should review its training course syllabus (to place) emphasis on go around, emergency procedures taking into account low visibility and somatogravic illusion.

• that the Libyan Civil Aviation Authority should develop a system for the supervision and control of medical examiners, including action to be taken in the event that sufficient evidence exists to demonstrate that a medical examiner has not performed his or her duties in accordance with the prescribed procedures.

• that Flight crew must immediately after landing report occurrences such as a go around to ATC and to the Company Safety Division before next flight and that ATC staff should be encouraged to report such events too.

• that ATC should report any abnormal occurrences associated with the operation of aircraft to the (relevant departments) in the Civil Aviation Authority.

• that Those conducting audits on AFRIQIYAH Airways (including the company quality system, LYCAA, and IATA Operational Safety Audit) should pay more attention to areas related to safety, operation and flight (data) analysis during their audits.

• that AFRIQIYAH Airways should make available and use a clear crew rest programme for augmented crew on long haul flights.

• that AFRIQIYAH Airways should make sure that somatogravic illusion phenomena is covered in pilot recurrent trainings.

• that AFRIQIYAH Airways should make a regular follow up and control on pilot performance emphasising on Crew CRM (make use of LOSA) and in particular to review the CRM training in order to minimize the gap between the CRM as prescribed in the manuals and how it is practiced during scheduled flights.

• that ATC Tower should consider downgrading of the airport fire category whenever the fire brigades or part of are engaged with an airport emergency.

• that the National Safety Board should properly train the rescue team to indicate and label the injured and victims in the crash site.

• that ICAO should review the requirement and the principles of the ELT.

• that the National Meteorological Centre should upgrade weather services at Tripoli International Airport as well as meteorological warnings (which) have to be issued in due time in case of significant weather change.

The main text of the Final Report of the Investigation was published on 28 February 2013. Twelve Appendices were also released as listed below. Appendix 11 consists of two illustrations which have both been included as illustrations above and acknowledged to source and Appendices 6, 7 and 12 are available for reference as indicated.

Appendix 1: Investigation Committee forming Resolution

Appendix 2: Transcript of the last 30 minutes of the SSCVR

Appendix 3: Nav. Aids calibration Report

Appendix 4: Victims Pathological Report

Appendix 5: Airport Information

Appendix 6: Study of Spatial Disorientation

Appendix 7: Study of Fatigue

Appendix 8: Side Stick Analysis and Examination

Appendix 9: Normal procedures / Non-precision approach in managed guidance

Appendix 10: Parameters from accident flight, with SSCVR extracts

Appendix 11: Chronology of end of accident flight

Appendix 12: Parameters from the 28 April 2010 flight

Similar Accidents and Incidents on SKYbrary

• A320, vicinity Bahrain Airport, Kingdom of Bahrain, 2000 (CFIT HF: On 23 August 2000, a Gulf Air Airbus A320 flew at speed into the sea during an intended dark night go around at Bahrain and all 143 occupants were killed. It was subsequently concluded that, although a number of factors created the scenario in which the accident could occur, the most plausible explanation for both the descent and the failure to recover from it was the focus on the airspeed indication at the expense of the ADI and the effect of somatogravic illusion on the recently promoted Captain which went unchallenged by his low-experience First Officer.

• A310, vicinity Quebec Canada, 2008 (LOC HF): On 5 March 2008, an Air Transat A310-300 was unintentionally mishandled by the flight crew during and shortly after departure from Quebec and effective control of the aircraft was temporarily lost. Whilst it was concluded that the origin of the initial difficulties in control were a result of confusion which began on the take off roll and led to a take off at excessive speed followed by subsequent mismanagement and overload, the inappropriate steep descent that followed was attributed to the effect of somatogravic illusion in respect of aircraft attitude control in conjunction with a singular focus on airspeed.

Further Reading

• Controlled Flight Into Terrain (CFIT)
• CFIT Precursors and Defences
• Cross-checking Process
• Response to a "PULL UP" Warning
• Crew Resource Management
• Fatigue
• Lessening the Effects of Visual Illusions
• Somatogravic and Somatogyral Illusions