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Accident and Serious Incident Reports: LOS

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Revision as of 16:10, 16 November 2010 by Editor1 (talk | contribs)
Article Information
Category: Loss of Separation Loss of Separation
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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

  • B752 / B752, en-route, north of Tenerife Spain 2011 (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.)
  • F100 / EC45, vicinity Bern Switzerland, 2012 (On 24 May 2012, a Fokker 100 descending visual downwind to land at Berne and an EC145 helicopter transiting the Bern CTR (Class 'D' airspace) VFR came within 0.7 nm horizontally and 75 ft vertically despite early traffic advice having been given to both aircraft. The Investigation attributed the conflict to the failure of the F100 crew to follow either their initial TCAS RA or a subsequent revised one and noted that although STCA was installed at Berne it had been disabled "many years before".)
  • GLF5 / A319, south-eastern France, 2004 (On 16 September 2004, a loss of separation occurred over Geneva between Air France A319 and a Gulfstream 5 which commenced descent without clearance by ATC and with coordinated TCAS RAs not followed by either aircraft.)
  • C525 / B773, vicinity London City UK, 2009 (On 27 July 2009, a Cessna 525 departing from London City failed to comply with the initial 3000 ft QNH SID Stop altitude and at 4000 ft QNH in day VMC came into close proximity on an almost reciprocal heading with a Boeing 777-300ER. Actual minimum separation was approximately 0.5nm laterally and estimated at between 100 ft and 200 ft vertically.)
  • DH8D / DH8D, vicinity Sudbury ON Canada, 2016 (On 14 October 2016, two Bombardier DHC8-400s received coordinated TCAS RAs as they came into opposite direction conflict near Sudbury, an uncontrolled airport, as one was descending inbound and emerging from an overcast layer and the other was level just below that layer after departing. Both aircraft crews ignored their RAs and their respective visual manoeuvring brought them to within 0.4nm at the same altitude. The Investigation noted that the conflict had occurred in Class ‘E’ airspace after the departing aircraft had cancelled IFR to avoid a departure delay attributable to the inbound IFR aircraft.)

... further results

Accepted ATC Clearance Not Followed

  • A319/B733, en-route, near Moutiers France, 2010 (On 8 July 2010 an Easyjet Airbus A319 on which line training was being conducted mis-set a descent level despite correctly reading it back and, after subsequently failing to notice an ATC re-iteration of the same cleared level, continued descent to 1000 feet below it in day VMC and into conflict with crossing traffic at that level, a Boeing 737. The 737 received and actioned a TCAS RA ‘CLIMB’ and the A319, which received only a TCAS TA, was given an emergency turn by ATC. The recorded CPA was 2.2 nm and 125 feet.)
  • F15 / B752, en-route, South East of Birmingham UK, 2000 (On 22 November 2000, near Birmingham UK, a dangerous loss of vertical and lateral separation occurred between a Boeing B757-200 being operated by Britannia Airways on a passenger flight and a formation flight of two F-15Es being operated by the United States Air Force (USAF).)
  • A310 / B736, en-route, Southern Norway, 2001 (On 21 February 2001, a level bust 10 nm north of Oslo Airport by a climbing PIA A310 led to loss of separation with an SAS B736 in which response to a TCAS RA by the A310 not being in accordance with its likely activation (descend). The B736 received and correctly actioned a Climb RA.)
  • EUFI / A321, en-route, near Clacton UK, 2008 (On 15 October 2008, following participation in a military exercise over East Anglia (UK), a formation of 2 foreign Eurofighters entered busy controlled airspace east north east of London without clearance while in the process of trying to establish the required initial contact with military ATC, resulting in loss of prescribed separation against several civil aircraft.)
  • BN2P / B763, vicinity Kagoshima Japan, 2015 (On 10 October 2015, a Britten-Norman BN2 instructed to join final behind a Boeing 767 instead joined in front of it which obliged the 767 crew to make a go around. The Investigation was unable to establish why the BN2 pilot failed to follow their conditional clearance but noted that the 'follow' clearance given onto final approach had not been accompanied by a sequence number, and when giving the aircraft type to be followed so that its sighting could be reported, the controller had not challenged the incomplete readback or repeated the aircraft type when subsequently issuing the clearance.)

... further results

"See and Avoid" Ineffective

  • B738/B738, vicinity Queenstown New Zealand, 2010 (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.)
  • H500 / D150, en-route, North of London UK, 2007 (On 5 October 2007, a loss of separation occurred between a Hughes 369 helicopter and a Jodel D150. The incident occurred outside controlled airspace, in VMC, and the estimated vertical separation as the Jodel took avoiding action by descending, was assessed by both pilots to be less than 50 feet.)
  • AS50 / PA32, en-route, Hudson River NJ USA, 2009 (On August 8, 2009 a privately operated PA32 and a Eurocopter AS350BA helicopter being operated by Liberty Helicopters on a public transport sightseeing flight collided in VMC over the Hudson River near Hoboken, New Jersey whilst both operating under VFR. The three occupants of the PA32, which was en route from Wings Field PA to Ocean City NJ, and the six occupants of the helicopter, which had just left the West 30th Street Heliport, were killed and both aircraft received substantially damaged.)
  • C525 / P180, south west of Sion Switzerland, 2012 (On 22 March 2013, a Cessna 525 inbound to Sion on a VFR clearance was flown into conflict with an IFR Piaggio P180 departing the same airport in compliance with its clearance and the prescribed separation between the two aircraft was lost in the vicinity of FL140. The Investigation concluded that an inappropriate ATC tactic had been employed in an attempt to achieve separation and recommended the development of a new procedure to better facilitate separation between IFR and VFR traffic in the airspace where the conflict occurred.)
  • NIM / AS32, vicinity RAF Kinloss UK, 2006 (On 17 October 2006, at night, in low cloud and poor visibility conditions in the vicinity of Kinloss Airfield UK, a loss of separation event occurred between an RAF Nimrod MR2 aircraft and a civilian AS332L Puma helicopter.)

... further results

Required Separation not Maintained

  • B738/B738, vicinity Oslo Norway, 2012 (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.)
  • H25B / AS29, en-route / manoeuvring, near Smith NV USA, 2006 (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.)
  • E145/E135, Chicago O’Hare USA, 2011 (On 8 August 2011, an Embraer 145 was given take off clearance from runway 32L at O’Hare in day VMC without the controller making the required check for potentially conflicting arrivals to runway 09R which pass over the runway. When the controller realised that the departing aircraft would conflict with an Embraer 135 approaching 09R, he told his aircraft to “stay low” and the runway 09R controller to send his aircraft around. Radar data indicated that the 135 on go around had crossed runway 32L about 125 feet above and just over 100 metres in front of the departing 145.)
  • B738/A319 en-route, south east of Zurich Switzerland, 2013 (On 12 April 2013, a Ryanair Boeing 737-800 took a climb clearance intended for another Ryanair aircraft on the same frequency. The aircraft for which the clearance was intended did not respond and the controller did not notice that the clearance readback had come from a different aircraft. Once the wrong aircraft began to climb, from FL360 to FL380, a TCAS RA to descend occurred due to traffic just transferred to a different frequency and at FL370. That traffic received a TCAS RA to climb. STCA was activated at the ATS Unit controlling both Ryanair aircraft.)
  • SF34/SF34, vicinity Stornoway UK, 2011 (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.)

... further results

Released to Own Separation

  • D328 / R44, Bern Switzerland, 2012 (On 2 June 2012, a Dornier 328 and a commercially-operated Robinson R44 helicopter came into close proximity within the airport perimeter whilst both were departing from Bern in VMC as cleared. The Investigation attributed the conflict to inappropriate issue of clearances by the controller in a context of an absence of both a defined final approach and take off area and fixed departure routes to the three designated departure points.)
  • B752/GLID, vicinity Glasgow UK, 2011 (On 23 July 2011 a Boeing 757 in Class ‘E’ airspace east of Glasgow in VMC encountered a glider ahead at the same altitude and deviated right to avoid a collision. The glider, climbing in a thermal, had not seen the 757 until it passed during avoiding action. The closest proximity was estimated as 100 metres at the same level as the glider passed to the left of the 757 in the opposite direction. Since the circumstances were considered to have demonstrated a safety critical risk by the UK CAA, an interim airspace reclassification Class ‘D’ was implemented)
  • B763/B738, vicinity Melbourne Australia, 2010 (On 5 December 2010 a Boeing 767-300 being operated by Qantas and departing Melbourne for Sydney in day VMC was following a Boeing 737-800 being operated by Virgin Australia which had also just departed Melbourne for Brisbane on the same SID and a loss of prescribed separation occurred. ATC became aware that the 767 was catching up with the 737 but were aware that it was in visual contact and therefore took no action to ensure separation was maintained. No TCAS activation occurred.)
  • ULAC / A319 vicinity Southend UK, 2013 (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".)
  • TOR / C152, en-route, Mattersey Nottinghamshire UK, 1999 (On 21 January 1999, a UK Royal Air Force Tornado GR1 and a private Cessna 152 collided in mid air, at low level in day VMC with the resultant loss of both aircraft and the death of all occupants.)

... further results

Level Bust

  • A310 / B736, en-route, Southern Norway, 2001 (On 21 February 2001, a level bust 10 nm north of Oslo Airport by a climbing PIA A310 led to loss of separation with an SAS B736 in which response to a TCAS RA by the A310 not being in accordance with its likely activation (descend). The B736 received and correctly actioned a Climb RA.)
  • B712, en-route, Western Australia, 2006 (On 28 February 2006, a Boeing 717-200 being operated by National Jet for Qantas Link on a domestic scheduled passenger flight from Paraburdoo to Perth, Western Australia in day IMC experienced an activation of the stall protection system just after the aircraft had levelled at a cruise altitude of FL340. The response of the flight crew was to initiate an immediate descent without either declaring an emergency or obtaining ATC clearance and, as a result, procedural separation against opposite direction traffic at FL320 was lost. The 72 occupants were uninjured and the aircraft was undamaged.)
  • B773, vicinity Houston TX USA, 2014 (On 3 July 2014, a Boeing 777-300 departing Houston came within 200 feet vertically and 0.61nm laterally of another aircraft after climbing significantly above the Standard Instrument Departure Procedure (SID) stop altitude of 4,000 feet believing clearance was to FL310. The crew responded to ATC avoiding action to descend and then disregarded TCAS 'CLIMB' and subsequently LEVEL OFF RAs which followed. The Investigation found that an inadequate departure brief, inadequate monitoring by the augmented crew and poor communication with ATC had preceded the SID non-compliance and that the crew should have followed the TCAS RAs issued.)
  • DH8D / B772, vicinity Sydney Australia, 2016 (On 9 December 2016, a Bombardier DHC8-400 departing Sydney lost prescribed separation against an inbound Boeing 777-200 after its crew failed to ensure that the aircraft levelled as cleared at 5,000 feet and this was exceeded by 600 feet. The Investigation found that the First Officer, as Pilot Flying, had disconnected the autopilot prior to routinely changing the selected airspeed because it tended to disconnect when this was done with altitude capture mode active but had then failed to re-engage it. The Captain's lack of effective monitoring was attributed to distraction as he sought to visually acquire the conflicting traffic.)
  • B738/A319 en-route, south east of Zurich Switzerland, 2013 (On 12 April 2013, a Ryanair Boeing 737-800 took a climb clearance intended for another Ryanair aircraft on the same frequency. The aircraft for which the clearance was intended did not respond and the controller did not notice that the clearance readback had come from a different aircraft. Once the wrong aircraft began to climb, from FL360 to FL380, a TCAS RA to descend occurred due to traffic just transferred to a different frequency and at FL370. That traffic received a TCAS RA to climb. STCA was activated at the ATS Unit controlling both Ryanair aircraft.)

... further results

Lateral Navigation Error

  • A320 / B789 / A343, San Francisco CA USA, 2017 (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.)
  • A319 / B735, vicinity Prague Czech Republic, 2012 (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.)
  • A320, en-route, Sydney Australia, 2007 (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.)
  • CRJ2/ATP, Stockholm Sweden, 2011 (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.)
  • D328 / R44, Bern Switzerland, 2012 (On 2 June 2012, a Dornier 328 and a commercially-operated Robinson R44 helicopter came into close proximity within the airport perimeter whilst both were departing from Bern in VMC as cleared. The Investigation attributed the conflict to inappropriate issue of clearances by the controller in a context of an absence of both a defined final approach and take off area and fixed departure routes to the three designated departure points.)

... further results

ATC Error

  • MD82 / A319, vicinity Helsinki Finland, 2007 (On 5 September 2007 in day VMC, an MD82 being operated by SAS was obliged to carry out an own-initiative avoiding action orbit in day VMC against an Airbus A319 being operated by Finnair on a scheduled passenger after conflict when about to join final approach. Both aircraft were following ATC instructions which, in the case of the MD 82, had not included maintaining own separation so that the applicable separation minima were significantly breached.)
  • C525 / P180, south west of Sion Switzerland, 2012 (On 22 March 2013, a Cessna 525 inbound to Sion on a VFR clearance was flown into conflict with an IFR Piaggio P180 departing the same airport in compliance with its clearance and the prescribed separation between the two aircraft was lost in the vicinity of FL140. The Investigation concluded that an inappropriate ATC tactic had been employed in an attempt to achieve separation and recommended the development of a new procedure to better facilitate separation between IFR and VFR traffic in the airspace where the conflict occurred.)
  • B773 / B738 / B738, Melbourne Australia, 2015 (On 5 July 2015, as a Boeing 777-300ER was departing Melbourne, two Boeing 737-800s which were initially on short final for intersecting runways with their ground separation dependent on one receiving a LAHSO clearance, went around. When both approaching aircraft did so, there was a loss of safe terrain clearance, safe separation and wake vortex separation between the three aircraft. The Investigation attributed the event to the actions of an inadequately supervised trainee controller and inappropriate intervention by a supervisory controller. It also identified a systemic safety issue generated by permitting LAHSO at night and a further flaw affecting the risk of all LAHSO at Melbourne.)
  • A320 / A320, Zurich Switzerland, 2011 (On 15 March 2011 two Swiss International Airlines’ Airbus A320 aircraft were cleared for simultaneous take off on intersecting runways at Zurich by the same controller. As both approached the intersection at high speed, the Captain of one saw the other and immediately rejected take off from 130 knots, stopping just at the edge of the intersection shortly after the other aircraft had flown low overhead unaware of the conflict. The Investigation noted a long history of similar incidents at Zurich and concluded that systemic failure of risk management had not been addressed by the air traffic control agency involved.)
  • A320 / A139 vicinity Zurich Switzerland, 2012 (On 29 May 2012, a British Airways Airbus A320 departing Zürich and in accordance with its SID in a climbing turn received and promptly and correctly actioned a TCAS RA 'CLIMB'. The conflict which caused this was with an AW 139 also departing Zürich IFR in accordance with a SID but, as this aircraft was only equipped with a TAS to TCAS 1 standard, the crew independently determined from their TA that they should descend and did so. The conflict, in Class 'C' airspace, was attributed to inappropriate clearance issue by the TWR controller and their inappropriate separation monitoring thereafter.)

... further results

Near Miss

  • A320 / GLID, vicinity Memmingen Germany, 2015 (On 6 April 2015, the crew of an A320 under radar control in Class E airspace and approaching 4000 feet made a very late sighting of a glider being flown by a student pilot which appeared ahead at a similar altitude. The glider pilot reported having seen a 'cone of light' coming towards him. Both aircraft took avoiding action as practicable and passed within a recorded 450 metres with the A320 passing an estimated 250 feet over the glider. The glider was not fitted with a transponder and was not required to be, and the controller had only secondary radar.)
  • A319/B733, en-route, near Moutiers France, 2010 (On 8 July 2010 an Easyjet Airbus A319 on which line training was being conducted mis-set a descent level despite correctly reading it back and, after subsequently failing to notice an ATC re-iteration of the same cleared level, continued descent to 1000 feet below it in day VMC and into conflict with crossing traffic at that level, a Boeing 737. The 737 received and actioned a TCAS RA ‘CLIMB’ and the A319, which received only a TCAS TA, was given an emergency turn by ATC. The recorded CPA was 2.2 nm and 125 feet.)
  • GLEX/F2TH, vicinity Ibiza Spain, 2012 (On 21 September 2012, two aircraft came into conflict in Class 'A' airspace whilst under radar control at night and loss of separation was resolved by TCAS RA responses by both aircraft. Investigation found that one of the aircraft had passed a procedurally-documented clearance limit without ATC clearance or intervention and that situational awareness of its crew had been diminished by communications with the conflicting aircraft being conducted in Spanish rather than English. A Safety Recommendation on resolving the "persistent problem" of such language issues was made, noting that a similar recommendation had been made 11 years earlier.)
  • A343 / B744, en-route, south of Newfoundland Canada, 1998 (On 20 July 1998, after an ATC error south of Newfoundland, an Air France A340 and an Air Canada 747-400 were on directly converging tracks and at the same level. Collision was avoided by the correct actioning of coordinated TCAS RAs by both aircraft.)
  • B738 / C172, en route, near Falsterbo Sweden, 2014 (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.)

... further results

Lateral Offset in Use

None on SKYbrary

Mid-Air Collision

None on SKYbrary

Uncommanded AP disconnect

None on SKYbrary

Military Aircraft Involved

  • BE20/SF34, vicinity Stornoway UK, 2011 (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.)
  • NIM / AS32, vicinity RAF Kinloss UK, 2006 (On 17 October 2006, at night, in low cloud and poor visibility conditions in the vicinity of Kinloss Airfield UK, a loss of separation event occurred between an RAF Nimrod MR2 aircraft and a civilian AS332L Puma helicopter.)
  • TOR / C152, en-route, Mattersey Nottinghamshire UK, 1999 (On 21 January 1999, a UK Royal Air Force Tornado GR1 and a private Cessna 152 collided in mid air, at low level in day VMC with the resultant loss of both aircraft and the death of all occupants.)
  • G115 / G115, near Porthcawl South Wales UK, 2009 (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)
  • C130 / C27J, manoeuvring, near Mackall AAF NC USA, 2014 (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.)

... further results

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Further Reading