Accident and Serious Incident Reports: LOS

Definition

Reports relating to accidents and incidents which involved Loss of Separation.

The accident and serious incident reports are grouped together below in subcategories.

TCAS RA Mis-flown

On 23 February 2018, an Embraer 195LR and an Airbus A320 on SIDs departing Brussels lost separation after the 195 was given a radar heading to resolve a perceived third aircraft conflict which led to loss of separation between the two departing aircraft. STCA and coordinated TCAS RA activations followed but only one TCAS RA was followed and the estimated minimum separation was 400 feet vertically when 1.36 nm apart. The Investigation found that conflict followed an error by an OJTI-supervised trainee controller receiving extended revalidation training despite gaining his licence and having almost 10 years similar experience in Latvia.

On 4 June 2016, a Boeing 737-800 instructed to climb from FL340 to FL380 by the controller of one sector in Bulgarian upper airspace came into sufficiently close proximity to an Airbus A320 under the control of a different sector controller to trigger co-ordinated TCAS RAs. Separation was eventually restored after the 737 followed its RA despite the A320, which had already deviated from its clearance on the basis of a prior TCAS TA without informing ATC, ignoring their RA. The Investigation found that the root cause of the conflict had been inadequate coordination between two vertically separated ATC sectors.

On 10 June 2011 an ATC error put a German Wings A319 and a Hahn Air Raytheon 390 on conflicting tracks over Switzerland and a co-ordinated TCAS RA followed. The aircraft subsequently passed in very close proximity without either sighting the other after the Hahn Air crew, contrary to Company procedures, followed an ATC descent clearance issued during their TCAS ‘Climb’ RA rather than continuing to fly the RA. The Investigation could find no explanation for this action by the experienced crew - both Hahn Air management pilots. The recorded CPA was 0.6 nm horizontally at 50 feet vertically.

On 20 November 2011, a problem in reading the altitude labels on the ATC radar control display led to a Finnair Boeing 757 being cleared to make a descent which brought it into proximity with a Thomas Cook Boeing 757 in day VMC. Co-ordinated TCAS RAs were generated onboard both aircraft but when the Finnair aircraft failed to respond to its Climb RA and continued descent, the other aircraft, which had responded correctly to its initial RA, received a further RA to reverse their descent to a climb. The Finnair aircraft reported retaining visual contact with the other aircraft throughout.

On 7 February 2011 two Air Inuit DHC8s came into head-to-head conflict en route over the eastern shoreline of Hudson Bay in non radar Class A airspace when one of them deviated from its cleared level towards the other which had been assigned the level 1000 feet below. The subsequent investigation found that an inappropriate FD mode had been used to maintain the assigned level of the deviating aircraft and noted deficiencies at the Operator in both TCAS pilot training and aircraft defect reporting as well as a variation in altitude alerting systems fitted to aircraft in the DHC8 fleet.

Accepted ATC Clearance Not Followed

On 23 February 2018, an Embraer 195LR and an Airbus A320 on SIDs departing Brussels lost separation after the 195 was given a radar heading to resolve a perceived third aircraft conflict which led to loss of separation between the two departing aircraft. STCA and coordinated TCAS RA activations followed but only one TCAS RA was followed and the estimated minimum separation was 400 feet vertically when 1.36 nm apart. The Investigation found that conflict followed an error by an OJTI-supervised trainee controller receiving extended revalidation training despite gaining his licence and having almost 10 years similar experience in Latvia.

On 4 June 2016, a Boeing 737-800 instructed to climb from FL340 to FL380 by the controller of one sector in Bulgarian upper airspace came into sufficiently close proximity to an Airbus A320 under the control of a different sector controller to trigger co-ordinated TCAS RAs. Separation was eventually restored after the 737 followed its RA despite the A320, which had already deviated from its clearance on the basis of a prior TCAS TA without informing ATC, ignoring their RA. The Investigation found that the root cause of the conflict had been inadequate coordination between two vertically separated ATC sectors.

On 10 June 2011 an ATC error put a German Wings A319 and a Hahn Air Raytheon 390 on conflicting tracks over Switzerland and a co-ordinated TCAS RA followed. The aircraft subsequently passed in very close proximity without either sighting the other after the Hahn Air crew, contrary to Company procedures, followed an ATC descent clearance issued during their TCAS ‘Climb’ RA rather than continuing to fly the RA. The Investigation could find no explanation for this action by the experienced crew - both Hahn Air management pilots. The recorded CPA was 0.6 nm horizontally at 50 feet vertically.

On 20 November 2011, a problem in reading the altitude labels on the ATC radar control display led to a Finnair Boeing 757 being cleared to make a descent which brought it into proximity with a Thomas Cook Boeing 757 in day VMC. Co-ordinated TCAS RAs were generated onboard both aircraft but when the Finnair aircraft failed to respond to its Climb RA and continued descent, the other aircraft, which had responded correctly to its initial RA, received a further RA to reverse their descent to a climb. The Finnair aircraft reported retaining visual contact with the other aircraft throughout.

On 7 February 2011 two Air Inuit DHC8s came into head-to-head conflict en route over the eastern shoreline of Hudson Bay in non radar Class A airspace when one of them deviated from its cleared level towards the other which had been assigned the level 1000 feet below. The subsequent investigation found that an inappropriate FD mode had been used to maintain the assigned level of the deviating aircraft and noted deficiencies at the Operator in both TCAS pilot training and aircraft defect reporting as well as a variation in altitude alerting systems fitted to aircraft in the DHC8 fleet.

"See and Avoid" Ineffective

On 20 June 2010, a Boeing 737-800 being operated by New Zealand company Pacific Blue AL on a scheduled passenger flight from Auckland to Queenstown lost IFR separation assurance against a Boeing 737-800 being operated by Qantas on a scheduled passenger flight from Sydney to Queenstown whilst both aircraft were flying a go around following successive but different instrument approaches at their shared intended destination. There were no abrupt manoeuvres and none of the respectively 88 and 162 occupants of the two aircraft were injured.

On 15 October 2017, a Falcon 2000EX on base leg for an easterly ILS approach at St Gallen-Altenrhein came into close proximity with a reciprocal track glider at 5000 feet QNH in Class ‘E’ airspace in day VMC with neither aircraft seeing the other until just before their minimum separation - 0.35 nm horizontally and 131 feet vertically - occurred. The Investigation attributed the conflict to the lack of relevant traffic separation requirements in Class E airspace and to the glider not having its transponder switched on and not listening out with the relevant ATC Unit.

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 12 October 2016, a BN2 Islander and a Bombardier DHC8-200 were involved in a near miss after the DHC8 took off from a runway which intersected with the runway on which the BN2 was about to land. The BN2 broke off its approach just before touchdown when the DHC8 was observed accelerating towards the runway intersection on its take-off roll. The Investigation noted that the aerodrome involved relied on visual separation and use of a CTAF and found that although both aircraft were aware of each other, the DHC8 crew failed to fully utilise visual lookout.

On 7 July 2015, a mid-air collision occurred between an F16 and a Cessna 150 in VMC at 1,600 feet QNH in Class E airspace north of Charleston SC after neither pilot detected the conflict until it was too late to take avoiding action. Both aircraft subsequently crashed and the F16 pilot ejected. The parallel civil and military investigations conducted noted the limitations of see-and-avoid and attributed the accident to the failure of the radar controller working the F16 to provide appropriate timely resolution of the impending conflict.

Required Separation not Maintained

On 22 December 2018, a Boeing 747-400 crew began to climb from FL310 without clearance and prescribed separation was lost against both an opposite direction Boeing 777-300 at FL 320 and another same direction Boeing 777-300 cleared to fly at FL330. The Investigation found that the 747 crew had requested FL 390 and then misunderstood the controller’s response of “level available 350” as a clearance to climb and gave a non-standard response and began to climb when the controller responded instructing the flight to standby for higher. Controller attempts to resolve the resultant ‘current conflict warnings’ were only partially successful.

On 27 September 2019, an Airbus A320 and an Embraer 145 both inbound to Barcelona and being positioned for the same Transition for runway 25R lost separation and received and followed coordinated TCAS RAs after which the closest point of approach was 0.8nm laterally when 200 feet vertically apart. The Investigation found that the experienced controller involved had initially created the conflict whilst seeking to resolve another potential conflict between one of the aircraft and a third aircraft inbound for the same Transition and having identified it had then implemented a faulty recovery plan and executed it improperly.

On 12 April 2019, a Boeing 717-200 commenced a go around at Strasbourg because the runway ahead was occupied by a departing Bombardier CRJ700 which subsequently, despite co-ordinated TCAS RAs, then came to within 50 feet vertically when only 740 metres apart laterally as the CRJ, whose crew did not see the 717, passed right to left in front of it. The Investigation attributed the conflict primarily to a series of flawed judgements by the TWR controller involved whilst also noting one absent and one inappropriate ATC procedure which respectively may have provided a context for the resultant risk.

On 26 June 2017, an Airbus A319 which had just taken off from Stuttgart came into conflict in Class ‘D’ airspace with a VFR light aircraft crossing its track and when, at 1,200 feet agl, the TCAS RA to descend which resulted was followed, an EGPWS Mode 3 Alert was generated. Clear of Conflict was annunciated after 10 seconds and climb resumed. The Investigation concluded that the light aircraft pilot had failed to follow the clearance which had been accepted and had caused the flight path conflict which was resolved by the response of the A319 to the TCAS RA.

On 29 March 2018, a Boeing 737-700 commenced a late go-around from landing at Amsterdam on a runway with an extended centreline which passed over another runway from which a Boeing 737-800 had already been cleared for takeoff. An attempt by the controller responsible for both aircraft to stop the departing aircraft failed because the wrong callsign was used, so low level divergent turns were given to both aircraft and 0.5nm lateral and 300 feet vertical separation was achieved. The Investigation concluded that the ATC procedure involved was potentially hazardous and made a safety recommendation that it should be withdrawn.

Released to Own Separation

Level Bust

On 12 November 1996, an Ilyushin IL76TD and an opposite direction Boeing 747-100 collided head on at the same level in controlled airspace resulting in the destruction of both aircraft and the loss of 349 lives. The Investigation concluded that the IL76 had descended one thousand feet below its cleared level after its crew had interpreted ATC advice of opposite direction traffic one thousand feet below as the reason to remain at FL150 as re-clearance to descend to this lower level. Fifteen Safety Recommendations relating to English language proficiency, crew resource management, collision avoidance systems and ATC procedures were made.

 

 

On 22 December 2018, a Boeing 747-400 crew began to climb from FL310 without clearance and prescribed separation was lost against both an opposite direction Boeing 777-300 at FL 320 and another same direction Boeing 777-300 cleared to fly at FL330. The Investigation found that the 747 crew had requested FL 390 and then misunderstood the controller’s response of “level available 350” as a clearance to climb and gave a non-standard response and began to climb when the controller responded instructing the flight to standby for higher. Controller attempts to resolve the resultant ‘current conflict warnings’ were only partially successful.

On 6 August 2011 an Easyjet Airbus A319 on which First Officer Line Training was in progress exceeded its cleared level during the climb after a different level to that correctly read back was set on the FMS. As a result, it came into conflict with an Alitalia A321 and this was resolved by responses to coordinated TCAS RAs. STCA alerts did not enable ATC resolution of the conflict and it was concluded that a lack of ATC capability to receive Mode S EHS DAPs - since rectified - was a contributory factor to the outcome.

On 31 December 2011 a USAF C12 Beech King Air descended 700 feet below the cleared outbound altitude on a procedural non precision approach to Stornoway in uncontrolled airspace in IMC and also failed to fly the procedure correctly. As a result it came into conflict with a Saab 340 inbound on the same procedure. The Investigation found that the C12 crew had interpreted the QNH given by ATC as 990 hPa as 29.90 inches, the subscale setting units used in the USA. The Saab 340 pilot saw the opposite direction traffic on TCAS and descended early to increase separation.

On 15 October 2011, a Loganair Saab 340 in uncontrolled airspace and inbound and level at 2000 feet QNH on a procedural non precision approach in day IMC to runway 18 at Stornoway received a TCAS RA ‘DESCEND’ when a second Loganair Saab 340 outbound on the same procedure descended prematurely to the same altitude contrary to ATC clearance. The subsequent investigation concluded that the failure of the controller to re-iterate the requirement to remain at 3000 feet outbound until advised had contributed the crew error. Minimum separation after the TCAS RA was less than 0.1nm horizontally when 500 feet vertically.

Lateral Navigation Error

On 11 May 2018, a Bombardier CRJ1000 climbing on departure from Tambolaka and an ATR72-500 descending inbound there lost safe separation when during opposite turns in visual flight in uncontrolled airspace. Prompt response to both coordinated TCAS RAs resolved the conflict. The Investigation found the departing flight Captain mixed up left and right downwind circuit joining by the ATR 72 and that his inexperienced First Officer had not picked this up. It also noted that this Captain may not have been fit for duty and that all parties may have failed to fully recognise the limitations of ANSP ‘information’ service.

On 21 January 2011, a Belarusian Bombardier CRJ200 failed to fly the prescribed missed approach procedure at night in IMC and when ATC observed a developing conflict with another aircraft which had just departed another runway with a conflicting clearance, both aircraft were given heading instructions to mitigate the proximity risk. The resulting CPA was 1.8nm at an altitude of 1600 feet. The subsequent investigation attributed the pilot error to a change of aircraft control in the flare when it became apparent that a safe landing was not assured.

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 7 July 2017 the crew of an Airbus A320, cleared for an approach and landing on runway 28R at San Francisco in night VMC, lined up for the visual approach for which it had been cleared on the occupied parallel taxiway instead of the runway extended centreline and only commenced a go-around at the very last minute, having descended to about 60 feet agl whilst flying over two of the four aircraft on the taxiway. The Investigation determined that the sole direct cause of the event was the poor performance of the A320 flight crew.

On 7 September 2012, the crew of an Air France Airbus A319 failed to follow their arrival clearance at destination and turned directly towards the ILS FAF and thereby into conflict with a Boeing 737-500 on an ILS approach. When instructed to turn left (and clear of the ILS) by the controller, the crew replied that they were following standard arrival which was not the case. As the separation between the two aircraft reduced, the controller repeated the instruction to the A319 to turn left and this was acknowledged. Minimum lateral separation was 1.7nm, sufficient to activate STCA.

ATC Error

On 23 February 2018, an Embraer 195LR and an Airbus A320 on SIDs departing Brussels lost separation after the 195 was given a radar heading to resolve a perceived third aircraft conflict which led to loss of separation between the two departing aircraft. STCA and coordinated TCAS RA activations followed but only one TCAS RA was followed and the estimated minimum separation was 400 feet vertically when 1.36 nm apart. The Investigation found that conflict followed an error by an OJTI-supervised trainee controller receiving extended revalidation training despite gaining his licence and having almost 10 years similar experience in Latvia.

On 12 April 2019, a Boeing 717-200 commenced a go around at Strasbourg because the runway ahead was occupied by a departing Bombardier CRJ700 which subsequently, despite co-ordinated TCAS RAs, then came to within 50 feet vertically when only 740 metres apart laterally as the CRJ, whose crew did not see the 717, passed right to left in front of it. The Investigation attributed the conflict primarily to a series of flawed judgements by the TWR controller involved whilst also noting one absent and one inappropriate ATC procedure which respectively may have provided a context for the resultant risk.

On 27 September 2019, an Airbus A320 and an Embraer 145 both inbound to Barcelona and being positioned for the same Transition for runway 25R lost separation and received and followed coordinated TCAS RAs after which the closest point of approach was 0.8nm laterally when 200 feet vertically apart. The Investigation found that the experienced controller involved had initially created the conflict whilst seeking to resolve another potential conflict between one of the aircraft and a third aircraft inbound for the same Transition and having identified it had then implemented a faulty recovery plan and executed it improperly.

On 12 May 2019, a Boeing 737-800 making its second procedural ILS approach to runway 25 at Reus came into conflict with an opposite direction light aircraft as the latter approached one of the designated VFR entry points having been instructed to remain well above the altitude which normally ensures separation of IFR and VFR traffic. The collision risk was resolved by TCAS RA promptly followed by the 737. The Investigation concluded that limiting the TWR radar display to the ATZ for controller training purposes had resulted in neither the trainee controller nor their supervisor being aware of the risk.

On 4 June 2016, a Boeing 737-800 instructed to climb from FL340 to FL380 by the controller of one sector in Bulgarian upper airspace came into sufficiently close proximity to an Airbus A320 under the control of a different sector controller to trigger co-ordinated TCAS RAs. Separation was eventually restored after the 737 followed its RA despite the A320, which had already deviated from its clearance on the basis of a prior TCAS TA without informing ATC, ignoring their RA. The Investigation found that the root cause of the conflict had been inadequate coordination between two vertically separated ATC sectors.

Near Miss

On 12 April 2019, a Boeing 717-200 commenced a go around at Strasbourg because the runway ahead was occupied by a departing Bombardier CRJ700 which subsequently, despite co-ordinated TCAS RAs, then came to within 50 feet vertically when only 740 metres apart laterally as the CRJ, whose crew did not see the 717, passed right to left in front of it. The Investigation attributed the conflict primarily to a series of flawed judgements by the TWR controller involved whilst also noting one absent and one inappropriate ATC procedure which respectively may have provided a context for the resultant risk.

On 29 June 2010, an Easyjet Switzerland Airbus A319 inbound to Basle-Mulhouse and an Air France Airbus A319 outbound from Basle-Mulhouse lost separation after an error made by a trainee APP controller under OJTI supervision during procedural service. The outcome was made worse by the excessive rate of climb of the Air France aircraft approaching its cleared level and both an inappropriate response to an initial preventive TCAS RA and a change of track during the ensuing short sequence of RAs by the Training Captain in command of and flying the Easyjet aircraft attributed by him to his situational ‘anxiety’.

On 20 June 2012, an ATR72-200 level at FL140 and a climbing opposite direction Jetstream 32 received and correctly responded to co-ordinated TCAS RAs after ATC error. The controller had not noticed visual MTCD and STCA alerts and had attempted to continue active controlling after a TCAS RA declaration. The Investigation observed that the ineffectiveness of visual conflict alerts had previously featured in a similar event at the same ACC and that the ANSP had advised then that its addition was planned. TCAS RA response controller training was considered to be in need of improvement to make it more effective.

On 5 November 2011, ATC cleared a Virgin Australia Boeing 737-700 to climb without speed restriction through an active parachute Drop Zone contrary to prevailing ATC procedures. As a result, prescribed separation from the drop zone was not maintained, but an avoiding action turn initiated by the 737 crew in VMC upon recognising the conflict eliminated any actual risk of collision with either the drop aircraft or its already-departed free-fall parachutists. The incident was attributed to a combination of inadequate controller training and inadequate ATC operational procedures.

On 10 June 2011 an ATC error put a German Wings A319 and a Hahn Air Raytheon 390 on conflicting tracks over Switzerland and a co-ordinated TCAS RA followed. The aircraft subsequently passed in very close proximity without either sighting the other after the Hahn Air crew, contrary to Company procedures, followed an ATC descent clearance issued during their TCAS ‘Climb’ RA rather than continuing to fly the RA. The Investigation could find no explanation for this action by the experienced crew - both Hahn Air management pilots. The recorded CPA was 0.6 nm horizontally at 50 feet vertically.

Lateral Offset in Use

none on SKYbrary

Mid-Air Collision

On 12 November 1996, an Ilyushin IL76TD and an opposite direction Boeing 747-100 collided head on at the same level in controlled airspace resulting in the destruction of both aircraft and the loss of 349 lives. The Investigation concluded that the IL76 had descended one thousand feet below its cleared level after its crew had interpreted ATC advice of opposite direction traffic one thousand feet below as the reason to remain at FL150 as re-clearance to descend to this lower level. Fifteen Safety Recommendations relating to English language proficiency, crew resource management, collision avoidance systems and ATC procedures were made.

 

 

On 1 December 2014, a night mid-air collision occurred in uncontrolled airspace between a Lockheed C130H Hercules and an Alenia C27J Spartan conducting VFR training flights and on almost reciprocal tracks at the same indicated altitude after neither crew had detected the proximity risk. Substantial damage was caused but both aircraft were successfully recovered and there were no injuries. The Investigation attributed the collision to a lack of visual scan by both crews, over reliance on TCAS and complacency despite the inherent risk associated with night, low-level, VFR operations using the Night Vision Goggles worn by both crews.

On 5 September 2015, a Boeing 737-800 cruising as cleared at FL350 on an ATS route in daylight collided with an opposite direction HS 125-700 which had been assigned and acknowledged altitude of FL340. The 737 continued to destination with winglet damage apparently causing no control impediment but radio contact with the HS 125 was lost and it was subsequently radar-tracked maintaining FL350 and continuing westwards past its destination Dakar for almost an hour before making an uncontrolled descent into the sea. The Investigation found that the HS125 had a recent history of un-rectified altimetry problems which prevented TCAS activation.

On 7 July 2015, a mid-air collision occurred between an F16 and a Cessna 150 in VMC at 1,600 feet QNH in Class E airspace north of Charleston SC after neither pilot detected the conflict until it was too late to take avoiding action. Both aircraft subsequently crashed and the F16 pilot ejected. The parallel civil and military investigations conducted noted the limitations of see-and-avoid and attributed the accident to the failure of the radar controller working the F16 to provide appropriate timely resolution of the impending conflict.

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.

Uncommanded AP disconnect

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Military Aircraft Involved

On 31 December 2011 a USAF C12 Beech King Air descended 700 feet below the cleared outbound altitude on a procedural non precision approach to Stornoway in uncontrolled airspace in IMC and also failed to fly the procedure correctly. As a result it came into conflict with a Saab 340 inbound on the same procedure. The Investigation found that the C12 crew had interpreted the QNH given by ATC as 990 hPa as 29.90 inches, the subscale setting units used in the USA. The Saab 340 pilot saw the opposite direction traffic on TCAS and descended early to increase separation.

On 1 December 2014, a night mid-air collision occurred in uncontrolled airspace between a Lockheed C130H Hercules and an Alenia C27J Spartan conducting VFR training flights and on almost reciprocal tracks at the same indicated altitude after neither crew had detected the proximity risk. Substantial damage was caused but both aircraft were successfully recovered and there were no injuries. The Investigation attributed the collision to a lack of visual scan by both crews, over reliance on TCAS and complacency despite the inherent risk associated with night, low-level, VFR operations using the Night Vision Goggles worn by both crews.

On 7 July 2015, a mid-air collision occurred between an F16 and a Cessna 150 in VMC at 1,600 feet QNH in Class E airspace north of Charleston SC after neither pilot detected the conflict until it was too late to take avoiding action. Both aircraft subsequently crashed and the F16 pilot ejected. The parallel civil and military investigations conducted noted the limitations of see-and-avoid and attributed the accident to the failure of the radar controller working the F16 to provide appropriate timely resolution of the impending conflict.

On 23 June 2014, a civil-operated Learjet 35 taking part in a German Air Force interception training exercise collided with the intercepting fighter aircraft as it began a follow-me manoeuvre. It became uncontrollable as a result of the damage sustained in the collision and crashed into terrain, killing both pilots. The Investigation found that whilst preparation for the exercise by all involved had been in compliance with requirements, these requirements had been inadequate, especially in respect of co-ordination between all the pilots involved, with both the civil and military safety regulatory authorities failing to detect and act on this situation.

On 11 February 2009, the plots of two civil-registered Grob 115E Tutors being operated for the UK Royal Air Force (RAF) and both operating from RAF St Athan near Cardiff were conducting Air Experience Flights (AEF) for air cadet passengers whilst in the same uncontrolled airspace in day VMC and aware of the general presence of each other when they collided. The aircraft were destroyed and all occupants killed

Apparent de-selection of transponder

On 29 September 2006, a Boeing 737-800 level at FL370 collided with an opposite direction Embraer Legacy at the same level. Control of the 737 was lost and it crashed, killing all 154 occupants. The Legacy's crew kept control and successfully diverted to the nearest suitable airport. The Investigation found that ATC had not instructed the Legacy to descend to FL360 when the flight plan indicated this and soon afterwards, its crew had inadvertently switched off their transponder. After the consequent disappearance of altitude from all radar displays, ATC assumed but did not confirm the aircraft had descended.

On 27 January 2005, two USAF-operated McDonnell Douglas F15E fighter aircraft, both continued to climb and both passed through the level of an Embraer 145 being operated by British Airways Regional on a scheduled passenger flight from Birmingham to Hannover, one seen at an estimated range of 100 feet.

Transponder non selection

On 11 March 2011, a Delta AL Boeing 757 departed Atlanta GA with no secondary radar indication visible to ATC and also failed to make contact with departure radar after accepting the frequency transfer instruction. During the eight minutes out of radio contact, it successively lost separation against two light aircraft and another passenger aircraft as it followed the cleared RNAV departure routing for eight minutes until the crew queried further climb on the TWR frequency and were invited to select their transponder on and contact the correct frequency.

On 15 October 2017, a Falcon 2000EX on base leg for an easterly ILS approach at St Gallen-Altenrhein came into close proximity with a reciprocal track glider at 5000 feet QNH in Class ‘E’ airspace in day VMC with neither aircraft seeing the other until just before their minimum separation - 0.35 nm horizontally and 131 feet vertically - occurred. The Investigation attributed the conflict to the lack of relevant traffic separation requirements in Class E airspace and to the glider not having its transponder switched on and not listening out with the relevant ATC Unit.

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 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 20 July 2014, the pilot of a VFR Cessna 172 became distracted and entered the Class 'C' controlled airspace of two successive TMAs without clearance. In the second one he was overtaken by a Boeing 738 inbound to Copenhagen with less than 90 metres separation. The 738 crew reported a late sighting of the 172 and seemingly assessed that avoiding action was unnecessary. Although the 172 had a Mode C-capable transponder, it was not transmitting altitude prior to the incident and the Investigation noted that this had invalidated preventive ATC and TCAS safety barriers and compromised flight safety.

Go Around Separation

On 12 April 2019, a Boeing 717-200 commenced a go around at Strasbourg because the runway ahead was occupied by a departing Bombardier CRJ700 which subsequently, despite co-ordinated TCAS RAs, then came to within 50 feet vertically when only 740 metres apart laterally as the CRJ, whose crew did not see the 717, passed right to left in front of it. The Investigation attributed the conflict primarily to a series of flawed judgements by the TWR controller involved whilst also noting one absent and one inappropriate ATC procedure which respectively may have provided a context for the resultant risk.

On 29 March 2018, a Boeing 737-700 commenced a late go-around from landing at Amsterdam on a runway with an extended centreline which passed over another runway from which a Boeing 737-800 had already been cleared for takeoff. An attempt by the controller responsible for both aircraft to stop the departing aircraft failed because the wrong callsign was used, so low level divergent turns were given to both aircraft and 0.5nm lateral and 300 feet vertical separation was achieved. The Investigation concluded that the ATC procedure involved was potentially hazardous and made a safety recommendation that it should be withdrawn.

On 31 October 2012, a Boeing 737-800 on go around after delaying the breaking off of a fast and high unstable ILS approach at Oslo lost separation in IMC against another aircraft of the same type and Operator which had just taken off from the same runway as the landing was intended to be made on. The situation was aggravated by both aircraft responding to a de-confliction turn given to the aircraft on go around. Minimum separation was 0.2nm horizontally when 500 feet apart vertically, both climbing. Standard missed approach and departure tracks were the same.

On 12 February 2019, an Airbus A320 under the command of a Captain reportedly undergoing line training supervised by a Training Captain occupying the supernumerary crew seat was slow to follow ATC instructions after breaking off from an unstabilised approach at London Stansted caused by the First Officer’s mismanagement of the approach and lost separation at night as it crossed approximately 600 feet above a Saab 340B climbing after takeoff. The Investigation found that flight crew workload had been exacerbated after the Captain under supervision unnecessarily delayed taking over control and had then not done so in the prescribed way.

On 7 October 2017, an arriving Boeing 787-9 and a departing Boeing 777-300 lost separation during intended use of runway 29 at Delhi when the 787-9 commenced a go around from overhead the runway because the departing 777-300 was still on the runway and came within 0.2 nm laterally and 200 feet vertically after ATC had failed to ensure that separation appropriate to mixed mode use was applied using speed control. The conflict was attributed to failure of the TWR controller to adhere to prevailing standard operating procedures.

UAV Involved

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Unregulated Manned Flight Involved

On 18 July 2013, an Airbus A319 level at 2000 feet QNH in Class G airspace and being radar vectored towards an ILS approach at Southend in day VMC had a sudden but brief base leg encounter with a paramotor which was not visible on radar and was seen too late for avoiding action to be practicable, before passing within an estimated 50 metres of the A319. The paramotor pilot could not subsequently be traced. The Investigation made a safety recommendation to the UK CAA to review the regulation and licensing of paramotor pilots.

Procedural Control

On 12 May 2019, a Boeing 737-800 making its second procedural ILS approach to runway 25 at Reus came into conflict with an opposite direction light aircraft as the latter approached one of the designated VFR entry points having been instructed to remain well above the altitude which normally ensures separation of IFR and VFR traffic. The collision risk was resolved by TCAS RA promptly followed by the 737. The Investigation concluded that limiting the TWR radar display to the ATZ for controller training purposes had resulted in neither the trainee controller nor their supervisor being aware of the risk.

On 5 September 2015, a Boeing 737-800 cruising as cleared at FL350 on an ATS route in daylight collided with an opposite direction HS 125-700 which had been assigned and acknowledged altitude of FL340. The 737 continued to destination with winglet damage apparently causing no control impediment but radio contact with the HS 125 was lost and it was subsequently radar-tracked maintaining FL350 and continuing westwards past its destination Dakar for almost an hour before making an uncontrolled descent into the sea. The Investigation found that the HS125 had a recent history of un-rectified altimetry problems which prevented TCAS activation.

On 31 March 2012, after the implementation of contingency ATC procedures for a period of 5 hours due to controller shortage, two Garuda A330 aircraft which had been transiting an associated Temporary Restricted Area (TRA) prior to re-entering controlled airspace were separately involved in losses of separation assurance, one when unexpectedly entering adjacent airspace from the TRA, the other when the TRA ceased and controlled airspace was restored. The Investigation did not find that any actual loss of separation had occurred but identified four Safety Issues in relation to the inadequate handling of the TRA activation by ANSP Airservices Australia.

On 2 August 2007, a Fokker F50 on an ILS approach to Maastricht in IMC came into close proximity inside the CTZ with an unseen light aircraft which had failed to comply with its Special VFR transit clearance. The Investigation found that the transiting aircraft had come within 0.14nm / 260 metres of the opposite direction F50 at a similar altitude without either aircraft having sight of the other, and that the Harvard had been wrongly assumed by ATC to be a helicopter after an initial lack of call sign prefix clarity on first contact had not been positively resolved.

ATC control using ADS-B

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ATC control supported by ADS-C

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Uncontrolled Airspace

On 11 May 2018, a Bombardier CRJ1000 climbing on departure from Tambolaka and an ATR72-500 descending inbound there lost safe separation when during opposite turns in visual flight in uncontrolled airspace. Prompt response to both coordinated TCAS RAs resolved the conflict. The Investigation found the departing flight Captain mixed up left and right downwind circuit joining by the ATR 72 and that his inexperienced First Officer had not picked this up. It also noted that this Captain may not have been fit for duty and that all parties may have failed to fully recognise the limitations of ANSP ‘information’ service.

On 1 December 2014, a night mid-air collision occurred in uncontrolled airspace between a Lockheed C130H Hercules and an Alenia C27J Spartan conducting VFR training flights and on almost reciprocal tracks at the same indicated altitude after neither crew had detected the proximity risk. Substantial damage was caused but both aircraft were successfully recovered and there were no injuries. The Investigation attributed the collision to a lack of visual scan by both crews, over reliance on TCAS and complacency despite the inherent risk associated with night, low-level, VFR operations using the Night Vision Goggles worn by both crews.

On 7 March 2017, an en-route Cessna Citation and a manoeuvring Ikarus C42 light aircraft approaching almost head-on at speeds of 240 knots and 55 knots respectively almost collided at an altitude of 3,500 feet in VMC outside controlled airspace. The Investigation found that only the C42 pilot had seen a conflicting aircraft and that they had then taken avoiding action which had mitigated the high risk of collision. The closest point of approach was recorded on radar as less than 100 feet vertically and less than 185 metres laterally. The near miss was categorised as an ICAO 'A' event.

On 12 October 2016, a BN2 Islander and a Bombardier DHC8-200 were involved in a near miss after the DHC8 took off from a runway which intersected with the runway on which the BN2 was about to land. The BN2 broke off its approach just before touchdown when the DHC8 was observed accelerating towards the runway intersection on its take-off roll. The Investigation noted that the aerodrome involved relied on visual separation and use of a CTAF and found that although both aircraft were aware of each other, the DHC8 crew failed to fully utilise visual lookout.

On 31 July 2015 a Saudi-operated Embraer Phenom on a private flight continued an unstabilised day visual approach to Blackbushe in benign weather conditions. The aircraft touched down with excess speed with almost 70% of the available landing distance behind the aircraft. It overran and was destroyed by impact damage and fire and all occupants died. The Investigation concluded that the combination of factors which created a very high workload for the pilot may have saturated his mental capacity, impeding his ability to handle new information and adapt his mental model leading to his continuation of a highly unstable approach.

TCAS RA Reversal

On 29 June 2010, an Easyjet Switzerland Airbus A319 inbound to Basle-Mulhouse and an Air France Airbus A319 outbound from Basle-Mulhouse lost separation after an error made by a trainee APP controller under OJTI supervision during procedural service. The outcome was made worse by the excessive rate of climb of the Air France aircraft approaching its cleared level and both an inappropriate response to an initial preventive TCAS RA and a change of track during the ensuing short sequence of RAs by the Training Captain in command of and flying the Easyjet aircraft attributed by him to his situational ‘anxiety’.

On 30 October 2014, a descending Airbus A320 came close to a Boeing 737-800 at around FL 220 after the A320 crew significantly exceeded a previously-instructed 2,000 fpm maximum rate of descent assuming it no longer applied when not reiterated during re-clearance to a lower altitude. Their response to a TCAS RA requiring descent at not above 1,000 fpm was to further increase it from 3,200 fpm. Lack of notification delayed the start of an independent Investigation but it eventually found that although the A320 TCAS equipment had been serviceable, its crew denied failing to correctly follow their initial RA.

On 2 September 2013, a B737 crew were not instructed to go around from their approach by ATC as it became increasingly obvious that an A320 departing the same runway would not be airborne in time for a landing clearance to be issued. They initiated a go around over the threshold and then twice came into conflict with the A320 as both climbed on similar tracks without ATC de-confliction, initially below the height where TCAS RAs are functional. Investigation attributed the conflict to ATC but the failure to effectively deal with the consequences jointly to ATC and both aircraft crews.

On 31 July 2015 a Saudi-operated Embraer Phenom on a private flight continued an unstabilised day visual approach to Blackbushe in benign weather conditions. The aircraft touched down with excess speed with almost 70% of the available landing distance behind the aircraft. It overran and was destroyed by impact damage and fire and all occupants died. The Investigation concluded that the combination of factors which created a very high workload for the pilot may have saturated his mental capacity, impeding his ability to handle new information and adapt his mental model leading to his continuation of a highly unstable approach.

On 13 October 2009, an Avro RJ100 being operated by Malmo Aviation on a scheduled passenger flight from Stockholm Bromma to Malmo in day VMC came into proximity with a unseen light aircraft crossing below which activated a TCAS RA which was followed. The flight crew were unaware that they were outside controlled airspace at the time. No abrupt manoeuvring occurred and none of the 85 occupants were injured.

VFR Aircraft Involved

On 26 June 2017, an Airbus A319 which had just taken off from Stuttgart came into conflict in Class ‘D’ airspace with a VFR light aircraft crossing its track and when, at 1,200 feet agl, the TCAS RA to descend which resulted was followed, an EGPWS Mode 3 Alert was generated. Clear of Conflict was annunciated after 10 seconds and climb resumed. The Investigation concluded that the light aircraft pilot had failed to follow the clearance which had been accepted and had caused the flight path conflict which was resolved by the response of the A319 to the TCAS RA.

On 12 May 2019, a Boeing 737-800 making its second procedural ILS approach to runway 25 at Reus came into conflict with an opposite direction light aircraft as the latter approached one of the designated VFR entry points having been instructed to remain well above the altitude which normally ensures separation of IFR and VFR traffic. The collision risk was resolved by TCAS RA promptly followed by the 737. The Investigation concluded that limiting the TWR radar display to the ATZ for controller training purposes had resulted in neither the trainee controller nor their supervisor being aware of the risk.

On 5 November 2011, ATC cleared a Virgin Australia Boeing 737-700 to climb without speed restriction through an active parachute Drop Zone contrary to prevailing ATC procedures. As a result, prescribed separation from the drop zone was not maintained, but an avoiding action turn initiated by the 737 crew in VMC upon recognising the conflict eliminated any actual risk of collision with either the drop aircraft or its already-departed free-fall parachutists. The incident was attributed to a combination of inadequate controller training and inadequate ATC operational procedures.

On 15 October 2017, a Falcon 2000EX on base leg for an easterly ILS approach at St Gallen-Altenrhein came into close proximity with a reciprocal track glider at 5000 feet QNH in Class ‘E’ airspace in day VMC with neither aircraft seeing the other until just before their minimum separation - 0.35 nm horizontally and 131 feet vertically - occurred. The Investigation attributed the conflict to the lack of relevant traffic separation requirements in Class E airspace and to the glider not having its transponder switched on and not listening out with the relevant ATC Unit.

On 22 September 2018, a Saab 340B taking off in accordance with its clearance at Nassau came close to a midair collision over the main runway after a light aircraft began an almost simultaneous takeoff in the opposite direction of the same runway contrary to its received and correctly acknowledged non-conflicting takeoff clearance for a different runway without the TWR controller noticing. The light aircraft passed over the Saab 340 without either aircraft crew seeing the other aircraft. The Investigation noted that the light aircraft pilot had “forgotten” his clearance and unconsciously substituted an alternative.

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Bureau d’Enquêtes et d’Analyses (BEA)

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