Überlingen mid-air collision

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Bashkirian Airlines Flight 2937
DHL Flight 611
Accident summary
Date 1 July 2002 (2002-07)
Summary Mid-air collision
Site Überlingen, Germany
47°46′42″N 9°10′26″E / 47.77833°N 9.17389°E / 47.77833; 9.17389Coordinates: 47°46′42″N 9°10′26″E / 47.77833°N 9.17389°E / 47.77833; 9.17389
Total fatalities 71 (all)
Total survivors 0
First aircraft

RA-85816, the aircraft involved in the accident, seen here at Stuttgart Airport in August 1997.
Type Tupolev Tu-154M
Operator Bashkirian Airlines
Registration RA-85816
Flight origin Domodedovo Int'l Airport[BFU 1][2]
Moscow, Russia
Destination Barcelona Int'l Airport
Barcelona, Spain
Passengers 60 (including 45 children)
Crew 9
Fatalities 69 (all)
Survivors 0
Second aircraft

G-BIKP, identical to the accident aircraft, seen here at Frankfurt Airport in 2003.
Type Boeing 757-23APF[1]
Operator DHL
Registration A9C-DHL
Flight origin Bahrain Int'l Airport[3][4]
Stopover Orio al Serio Airport
Bergamo, Italy
Destination Brussels Airport
Brussels, Belgium
Passengers 0
Crew 2
Fatalities 2 (all)
Survivors 0
Site of the crash is located in Germany
Site of the crash
Site of the crash
The crash occurred at approximately 47° 46′ 42″ N, 9° 10′ 26″ E.
Memorial tablet "Die zerrissene Perlenkette".
Memorial tablet.
Überlingen memorial.

The Überlingen mid-air collision occurred at 21:35 UTC on 1 July 2002 between Bashkirian Airlines Flight 2937 (a Tupolev Tu-154M passenger jet carrying 60 passengers – mostly children – and 9 crew) and DHL Flight 611 (a Boeing 757-23APF cargo jet manned by two pilots) over the towns of Überlingen and Owingen in southern Germany. All 71 people on board the two aircraft were killed.[5]

Less than two years later, on 26 February 2004, Peter Nielsen, the air traffic controller on duty at the time of the accident, was stabbed to death by an architect, Vitaly Kaloyev,[6] who had lost his wife and two children in the accident. Nielsen was 36 years old.[7][8]

On 19 May 2004, the German Federal Bureau of Aircraft Accidents Investigation (BFU) published its determination that the accident had been caused by shortcomings in the Swiss air traffic control system supervising the flights at the time of the accident and by ambiguities in the use of TCAS, the on-board aircraft collision avoidance system.[BFU 2]

Flights involved[edit]

Bashkirian Airlines Flight 2937 was a chartered flight from Moscow, Russia to Barcelona, Spain, carrying sixty passengers and nine crew. Forty-five of the passengers were Russian schoolchildren from the city of Ufa in Bashkortostan on a school trip organized by the local UNESCO committee to the Costa Daurada area of Spain.[2][3][9][10] Most of the parents of the children were high-ranking officials in Bashkortostan.[11] One of the fathers was the head of the local UNESCO committee.[12]

The aircraft, a Tupolev Tu-154M registered as RA-85816, was piloted by an experienced Russian crew: 52-year-old Captain Alexander Mihailovich Gross (Александр Михайлович Гросс) and 40-year-old First Officer Oleg Pavlovich Grigoriev (Олег Павлович Григорьев). The captain had more than 12,000 flight hours to his credit. Grigoriev, the chief pilot of Bashkirian Airlines, had 8,500 hours of flying experience and his task was to evaluate Captain Gross's performance throughout the flight. 41-year-old Murat Ahatovich Itkulov (Мурат Ахатович Иткулов), a seasoned pilot with close to 7,900 flight hours who was normally the first officer, did not officially serve on duty due to the captain's assessment. 50-year-old Sergei Kharlov, a flight navigator with approximately 13,000 flight hours, and 37-year-old Flight Engineer Oleg Valeev, who had almost 4,200 flight hours, joined the three pilots in the cockpit.[13]

DHL Flight 611, a Boeing 757-23APF cargo aircraft registered as A9C-DHL, had originated in Bahrain and was being flown by two Bahrain-based[3][14] pilots, 47-year-old British Captain Paul Phillips and 34-year-old Canadian First Officer Brant Campioni.[10] Both pilots were very experienced – the captain had clocked close to 12,000 flight hours and the first officer had accumulated more than 6,600 flight hours. At the time of the accident, the aircraft was en route from Bergamo, Italy to Brussels, Belgium.


The two aircraft were flying at flight level 360 (36,000 feet, 10,973 m) on a collision course. Despite being just inside the German border, the airspace was controlled from Zürich, Switzerland, by the private Swiss airspace control company Skyguide. The only air traffic controller handling the airspace, Peter Nielsen, was working two workstations at the same time. He did not realize the problem in time and thus failed to keep the aircraft at a safe distance from each other. Only less than a minute before the accident did he realize the danger and contacted Flight 2937, instructing the pilot to descend by a thousand feet to avoid collision with crossing traffic (Flight 611). Seconds after the Russian crew initiated the descent, however, their traffic collision avoidance system (TCAS) instructed them to climb, while at about the same time the TCAS on Flight 611 instructed the pilots of that aircraft to descend.[BFU 3] Had both aircraft followed those automated instructions, the collision would not have occurred.[BFU 4]

Flight 611's pilots on the Boeing jet followed the TCAS instructions and initiated a descent, but could not immediately inform Nielsen because the controller was dealing with Flight 2937. About eight seconds before the collision, Flight 611's descent rate was about 2,400 feet per minute (12 m/s), not as rapid as the 2,500 to 3,000 ft/min (13 to 15 m/s) range advised by TCAS. Having already commenced his descent, as instructed by the controller, the pilot on the Tupolev disregarded the TCAS instruction to climb,[BFU 5] thus both planes were now descending.

Unaware of the TCAS-issued alerts, Nielsen repeated his instruction to Flight 2937 to descend, giving the Tupolev crew incorrect information as to the position of the DHL plane. Maintenance work was being carried out on the main radar system, which meant that the controllers were forced to use a slower system.[BFU 6]

The aircraft collided at almost a right angle at an altitude of 34,890 feet (10,630 m), with the Boeing's vertical stabilizer slicing completely through Flight 2937's fuselage just ahead of the Tupolev's wings. The Tupolev exploded and broke into several pieces, scattering wreckage over a wide area. The nose section of the aircraft fell vertically, while the tail section with the engines continued, stalled, and fell. The crippled Boeing, now with 80% of its vertical stabilizer lost, struggled for a further seven kilometres (four miles) before crashing into a wooded area close to the village of Taisersdorf at a 70-degree downward angle. Each engine ended up several hundred metres away from the main wreckage, and the tail section was torn from the fuselage by trees just before impact. All 69 people on the Tupolev, and the two on board the Boeing, died.[BFU 7]

Other factors in the crash[edit]

Only one air traffic controller, Peter Nielsen of ACC Zurich, was controlling the airspace through which the aircraft were flying. The other controller on duty was resting in another room for the night. This was against the regulations, but had been a common practice for years and was known and tolerated by management. The ground-based optical collision warning system, which would have alerted the controller to imminent collisions early, had been switched off for maintenance; Nielsen was unaware of this. There still was an aural STCA warning system, which released a warning addressed to workstation RE SUED at 21:35:00 (32 seconds before the collision); this warning was not heard by anyone present at that time, although no error in this system could be found in a subsequent technical audit; whether this audible warning is turned on or not, is not logged technically. Even if Nielsen had heard this warning, at that time finding a useful resolution order by the air traffic controller is impossible.[BFU 8]

Deviating statements in the official report[edit]

All countries involved could add additional "deviating" statements to the official report. The Kingdom of Bahrain, Switzerland, and the Russian Federation did submit positions that were published with the official report. The USA did not submit deviating positions. The deviating statements were published verbatim as an appendix to the report by the German federal investigators.[15]

The statement by the Kingdom of Bahrain, the home country of the DHL plane, mostly agrees with the findings of the report. It says that the report should have put less emphasis on the actions of individuals and stressed the problems with the organisation and management more. Bahrain's statement also mentions the lack of crew resource management in the Tupolev's cockpit as a factor in the crash.[15]

The Russian Federation states that the Russian pilots were unable to obey the TCAS advisory to climb; the advisory was given when they were already at 35500 feet while the controller wrongly stated there was conflicting traffic above them at 36000 feet. Also, the controller gave the wrong position of the DHL plane (2 o'clock instead of the actual 10 o'clock). Russia asserts that the DHL crew had a "real possibility" to avoid a collision since they were able to hear the conversation between the Russian crew and the controller.[15]

Switzerland notes that the Tupolev was about 33 metres below the flight level ordered by the Swiss controller, and still descending at 1900 feet per minute. The Swiss say that this was also a cause of the accident. The Swiss position also states that in spite of the false information given (position and phraseology) by the Swiss controller the TCAS advisories would have been useful if obeyed immediately.[15]


Skyguide memorial to the aviation accident and murder of Peter Nielsen.

Nielsen needed medical attention due to traumatic stress caused by the accident.[16] At Skyguide, his former colleagues maintained a vase with a white rose over Nielsen's former workstation.[17] Skyguide, after initially having blamed the Russian pilot for the accident, accepted full responsibility and asked relatives of the victims for forgiveness.[18] On 19 May 2004, the official investigators found that managerial incompetence and systems failures were the main cause of the accident.

On 27 July 2006, a court in Konstanz decided that the Federal Republic of Germany should pay compensation to Bashkirian Airlines. The court found that it was illegal for the state to allow a foreign private company to provide air traffic control in German airspace. The government appealed the ruling, and a final decision is still pending as of 2008.[19]

In another case before the court in Konstanz, Skyguide's liability insurance is suing Bashkirian Airlines for 2.5 million euro in damages. The case was opened in March 2008; the legal questions are expected to be difficult, as the airline has filed for bankruptcy under Russian law.[19]

A criminal investigation of Skyguide began in May 2004. On 7 August 2006, a Swiss prosecutor filed manslaughter charges against eight employees of Skyguide. The Winterthur prosecutor called for prison terms of 6 to 15 months, alleging "homicide by negligence".[20] The verdict was announced in September 2007. Three of the four managers convicted were given suspended prison terms and the fourth was ordered to pay a fine. Another four employees of the Skyguide firm were cleared of any wrongdoing.[21]

TCAS and conflicting orders[edit]

The accident raised questions on how pilots must react when they receive conflicting orders from the TCAS and from air traffic control (ATC). TCAS was a relatively new technology at the time of the accident, having been mandatory[Note 1] in Europe since 2000.[BFU 9] Whilst the TCAS is programmed to assume that both crews will promptly follow the system's instructions, the operations manual did not clearly state that TCAS should always take precedence over any ATC commands.[BFU 10]

When a resolution advisory (RA) occurs, the pilot flying should respond immediately by direct attention to RA displays and maneuver as indicated, unless doing so would jeopardize the safe operation of the flight, or unless the flight crew can assure separation with the help of definitive visual acquisition of the aircraft causing the RA.[22] In responding to a TCAS RA that directs a deviation from assigned altitude, communicate with ATC as soon as practicable after responding to the RA. When the RA is removed, the flight crew should advise ATC that they are returning to their previously assigned clearance or should acknowledge any amended clearance issued.[22]

The TCAS Pilot's Guide was ambiguous as to whether or not TCAS advisories should take precedence over ATC instructions.[BFU 11] This ambiguity was replicated in the Tu-154 Flight Operations Manual, which contained contradictory sections. On the one hand, chapter emphasized the role of the ATC and describes the TCAS as an "additional aid",[BFU 12] whilst chapter forbids manoeuvers contrary to the TCAS.[BFU 13] The BFU recommended that this ambiguity should be resolved in favor of obeying TCAS advisories even when these were in conflict with ATC instructions.[BFU 14]

Prior incidents[edit]

About a year before the Bashkirian Airlines-DHL collision there had already been another incident involving confusion between conflicting TCAS and ATC commands. During a 2001 Japan Airlines mid-air incident, two Japanese airliners nearly collided with each other in Japanese skies. Both aircraft had received conflicting orders from the TCAS and ATC; one pilot followed the instructions of the TCAS while the other did not. A collision was only averted because one of the pilots made evasive maneuvers based on a visual judgement. The aircraft missed each other by about 11 metres (36 ft), and the abrupt maneuver necessary to avert disaster left about 100 occupants injured on one aircraft, some seriously. As a consequence Japan called for measures to prevent similar incidents. However, the International Civil Aviation Organization (ICAO) did not take action until after the crash over Germany in 2002.[23] In addition four near misses in Europe occurred before the German disaster, because one set of pilots obeyed the air traffic controllers while the other obeyed TCAS.[citation needed] The ICAO decided to fulfill Japan's request 18 months after the Japan Airlines incident.[citation needed]

Technical solutions[edit]

Before this accident a change proposal (CP 112)[24] for the TCAS II system had been issued. This proposal would have created a "reversal" of the original warning – asking the DHL plane to climb and the Tupolev crew to descend.[BFU 15] According to an analysis by Eurocontrol this would have avoided the collision if the DHL crew had followed the new instructions and the Tupolev had continued to descend.[BFU 15] All new aircraft since March 2012 are fitted with TCAS II version 7.1 which includes this reversal logic, and existing aircraft must be upgraded before December 2015.[25]

Additionally, an automatic downlink for the TCAS – which would have alerted the controller that a TCAS advisory had been issued to the aircraft under his control, and notified him of the nature of that advisory – had not been deployed worldwide at the time of the accident.[BFU 16]

Recommendations after the accident[edit]

The investigation report contains a number of recommendations concerning TCAS, calling for upgrades and for better training and clearer instructions to the pilots.[BFU 17]

Notable passengers on Flight 2937[edit]

Fourteen-year old Kirill Degtyarev created paintings from age 4 to his death and had held two public exhibitions. After his death, Ufa hosted one exhibition and Überlingen hosted another exhibition.[13]

Murder of Peter Nielsen[edit]

Main article: Vitaly Kaloyev

Devastated by the loss of his wife and two children aboard flight 2937, Vitaly Kaloyev held Peter Nielsen responsible for their deaths. He stabbed Nielsen to death at his home in Kloten, near Zürich, on 24 February 2004.[17][26] Police arrested Kaloyev at a local motel not long after the murder, and he was subsequently convicted of the crime in 2005. He was released on 8 November 2007 because his mental condition was not sufficiently considered in the initial sentence. After his release, Kaloyev was dubbed a "hero" in North Ossetia. In January 2008, he was appointed deputy construction minister of North Ossetia.[27]


The Discovery Channel Canada documentary series Mayday featured this accident in the episode titled Deadly Crossroads, which was released in 2004.[28]

The National Geographic Channel documentary series Seconds From Disaster featured this mid-air collision in the episode entitled Collision at 35,000 feet release in 26 September 2011.

"Flug in die Nacht – Das Unglück von Überlingen" (2009), ("Flight into the night – the accident at Überlingen") produced by German and Swiss TV stations SWR and SF, is a motion picture based on the crash and the subsequent killing of the air traffic controller.[29]

See also[edit]

Other mid-air collisions:


  1. ^ TCAS was mandatory for aircraft with a maximum certified take-off weight of over 30 tonnes or a seating capacity of over thirty passengers. Both aircraft involved in this accident met the criteria for mandatory TCAS installation.


  1. ^ "A9C-DHL DHL International Boeing 757-23APF - cn 24635 / ln 258 - Planespotters.net". planespotters.net. Archived from the original on 11 October 2008. Retrieved 6 September 2008. 
  2. ^ a b Gallagher, Paul (9 July 2002). "Jet pilot's 14 seconds dilemma before fatal crash". The Scotsman (Edinburgh). Archived from the original on 19 January 2008. Retrieved 18 January 2007. 
  3. ^ a b c "Vain attempt to avert deadly crash". CNN. 2 July 2002. Retrieved 9 April 2010. [dead link]
  4. ^ "Mid-air collision of 1 July 2002: sequence of events" (Skyguide).[dead link]
  5. ^ "Passenger List". Archived from the original on 29 October 2008. Retrieved 21 November 2008. 
  6. ^ Boyes, Roger (26 October 2005). "Father killed air traffic chief over fatal crash". The Sunday Times (London). Retrieved 28 December 2010. 
  7. ^ Wolfsteller, Pilar (26 October 2005). "Father 'saw black' as he killed air traffic controller". The Scotsman (Edinburgh). Archived from the original on 19 January 2008. Retrieved 18 January 2007. 
  8. ^ Harding, Luke; Paton Walsh, Nick (28 February 2004). "Nothing left to lose: grief-crazed murder suspect haunted by family's air deaths". The Guardian (London). Retrieved 8 April 2008. 
  9. ^ Koïchiro Matsuura (3 July 2002). "Address by Mr Koïchiro Matsuura, Director-General of UNESCO, on receiving the International Prize of St Andrew for promoting dialogue among civilizations" (PDF (12KiB)). UNESCO. Retrieved 9 April 2010. 
  10. ^ a b Wild, Matthew. "Family devastated by pilot's death". North Shore News. Retrieved 18 January 2007. [dead link]
  11. ^ "Children's holiday party on doomed plane." CNN. 4 July 2002. Retrieved on 28 April 2010.[dead link]
  12. ^ http://www.newsru.com/world/02jul2002/aviacrash.html
  13. ^ a b "Deadly Crossroads," Mayday
  14. ^ "British pilot 'tried to avert disaster'". BBC. 2 July 2002. Archived from the original on 6 May 2008. Retrieved 8 April 2008. 
  15. ^ a b c d "Appendices/Deviating positions for Investigation Report AX001-1-2/02 MAY 2004" (PDF). Retrieved 5 May 2008. 
  16. ^ "Air crash safety device switched off". BBC NEWS. 3 July 2002. Retrieved 14 July 2009. 
  17. ^ a b "Information regarding the air accident at Überlingen on 1 July 2002". Skyguide. Retrieved 14 July 2009. [dead link]
  18. ^ "Plane crash killing trial starts". BBC News. 25 October 2005. Retrieved 8 April 2008. 
  19. ^ a b "Katastrophe von Überlingen – Flugunglück beschäftigt Landgericht". Stuttgarter Zeitung. 20 April 2008. Retrieved 7 June 2009. [dead link]
  20. ^ "Swiss go on trial over air crash". BBC. 15 May 2007. Retrieved 15 May 2007. 
  21. ^ "Four guilty over Swiss air crash". BBC. 4 September 2007. Retrieved 8 April 2008. 
  22. ^ a b http://www.faa.gov/documentLibrary/media/Advisory_Circular/TCAS%20II%20V7.1%20Intro%20booklet.pdf
  23. ^ "report outline". ICAO. Archived from the original on 29 September 2007. Retrieved 22 January 2007. 
  24. ^ Change proposal CP112E
  25. ^ "TCAS II Version 7.1 Requirements Coming to European Union". National Business Aviation Association. March 30, 2012. Retrieved 2015-02-22. 
  26. ^ "Swiss air crash controller killed." CNN. Wednesday 25 February 2004. Retrieved on 29 January 2010.
  27. ^ Franchetti, Mark (10 February 2008). "Russia hails Vitaly Kaloyev a hero". The Sunday Times (London). Retrieved 10 March 2009. 
  28. ^ IMDb
  29. ^ Flug in die Nacht – Das Unglück von Überlingen at the Internet Movie Database

Official report[edit]

"Investigation Report AX001-1-2" (PDF). German Federal Bureau of Aircraft Accidents Investigation. 2 May 2004. Archived from the original on 23 January 2007. Retrieved 17 January 2007. 

  1. ^ Section 1.1 "History of the flights", page 6
  2. ^ Section 3.2 "Causes", page 110
  3. ^ Section 4 "Safety Recommendations", pages 111-113
  4. ^ Section 1.16.2 "ACAS/TCAS II analysis", page 34
  5. ^ Section 2.7 "Analysis summary", pages 104-106
  6. ^ Section 1.17.1 "ATC Zurich", pages 35-42
  7. ^ Section 1.2 "Injuries to persons", page 9
  8. ^ page 89
  9. ^ page 45
  10. ^ page 103: "Paragraph 6.1 of the TCAS Pilot's Guide states "TCAS 2000 is intended as a back-up to visual collision avoidance, application of 'right-of-way' rules, and ATC separation services", and leaves a degree of ambiguity over the interpretation of the term 'back-up'."
  11. ^ page 80 "The wording "TCAS is a backup to the ATC system..." could be interpreted that ATC takes priority to TCAS"
  12. ^ page 53 "For the avoidance of in-flight collisions is the visual control of the situation in the airspace by the crew and the correct execution of all instructions issued by the Air Traffic Controller to be viewed as the most important tool. TCAS is an additional instrument which ensures the timely determination of oncoming traffic, the classification of the risk and, if necessary, planning of an advice for a vertical avoidance manoeuvre." - TU154M Flight Operations Manual
  13. ^ page 103
  14. ^ page 111 "Safety Recommendation 18/2003"
  15. ^ a b page 35
  16. ^ page 50
  17. ^ Section 4 "Safety Recommendations", pages 111-113

External links[edit]

On conflicting orders[edit]