Überlingen mid-air collision
|Date||1 July 2002|
|Summary||Collision caused by ATC confusion and compounded by ambiguity in TCAS operation|
|Total fatalities||71 (all)|
RA-85816, the accident aircraft, at Cologne Bonn Airport on July 1998, prior to its lease to Transeuropean Airlines.
|Flight origin||Domodedovo Int'l Airport[BFU 1]
|Destination||Barcelona Int'l Airport
|Passengers||60 (including 45 children)|
A9C-DHL, the Boeing 757 involved in the accident, at Brussels Airport in August 1996.
|Registration||A9C-DHL [Note 1]|
|Flight origin||Bahrain Int'l Airport
|Stopover||Orio al Serio Airport
On 1 July 2002, Bashkirian Airlines Flight 2937, a Tupolev Tu-154 passenger jet, and DHL Flight 611, a Boeing 757 cargo jet, collided in mid-air over Überlingen, a southern German town on Lake Constance, at 23:35 local time. All 69 passengers and crew aboard the Tu-154 and the two crew members aboard the Boeing 757 were killed.
The official investigation by the German Federal Bureau of Aircraft Accident Investigation (German: Bundesstelle für Flugunfalluntersuchung, (BFU)) identified as the main cause of the collision a number of shortcomings on the part of the Swiss air traffic control service in charge of the sector involved, and also ambiguities in the procedures regarding the use of TCAS, the on-board aircraft collision avoidance system.[BFU 2]
Two years after the crash, Peter Nielsen, the air traffic controller on duty at the time of the collision, was murdered in an apparent act of revenge by Vitaly Kaloyev, a Russian citizen who had lost his wife and two children in the accident.
- 1 Flights involved
- 2 Accident
- 3 Other factors in the crash
- 4 Aftermath
- 5 TCAS and conflicting orders
- 6 In popular culture
- 7 See also
- 8 Notes
- 9 References
- 10 External links
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 Dorada area of Spain. Most of the parents of the children were high-ranking officials in Bashkortostan. One of the fathers was the head of the local UNESCO committee.
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 Gennadyevich Kharlov (Сергей Геннадьевич Харлов), a flight navigator with approximately 13,000 flight hours, and 37-year-old Flight Engineer Oleg Irikovich Valeev (Олег Ирикович Валеев), who had almost 4,200 flight hours, joined the three pilots in the cockpit.
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 pilots, 47-year-old British Captain Paul Phillips and 34-year-old Canadian First Officer Brant Campioni. Both pilots were very experienced – the captain had logged 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. Partly due to the added workload, and partly due to delayed radar data, he did not realise 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 realise 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 (telling them that the Boeing was to the right of the Tupolev when it was in fact to the left).[BFU 6]
The aircraft collided at 23:35:32, 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 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.[BFU 7] All 69 people on the Tupolev, and the two on board the Boeing, died.[BFU 8]
Other factors in the crash
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,[vague] but had been a common practice for years and was known and tolerated by management. Maintenance work was being carried out on the main radar image processing system, which meant that the controllers were forced to use a fallback system.[BFU 9] The ground-based optical collision warning system, which would have alerted the controller to the pending collision approximately 2½ minutes before it happened,[BFU 10] had been switched off for maintenance; Nielsen was unaware of this.[BFU 11] There still was an aural STCA warning system, which released a warning addressed to workstation RE SUED at 23:35:00 (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 12]
Deviating statements in the official report
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 U.S. did not submit deviating positions. The deviating statements were published verbatim as an appendix to the report by the German federal investigators.
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 more on the faults within Skyguide's organisation and management. Bahrain's statement also mentions the lack of crew resource management in the Tupolev's cockpit as a factor in the crash.
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 35,500 feet (10,800 m) while the controller wrongly stated there was conflicting traffic above them at 36,000 feet (11,000 m). 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.
Switzerland notes that the Tupolev was about 33 metres (108 ft) below the flight level ordered by the Swiss controller, and still descending at 1,900 feet per minute (580 m/min). The Swiss say that this was also a cause of the accident. Switzerland also requested that the BFU make a formal finding that the TCAS advisories would have been useful if obeyed immediately; the BFU declined to do so.
Nielsen needed medical attention due to traumatic stress caused by the accident. At Skyguide, his former colleagues maintained a vase with a white rose over Nielsen's former workstation. Skyguide, after initially having blamed the Russian pilot for the accident, accepted full responsibility and asked relatives of the victims for forgiveness.
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 Germany was legally responsible for the actions of Skyguide. The government appealed the ruling; however, in the autumn of 2013 Bashkirian Airlines and the Federal Republic of Germany reached a tacit agreement, ending the court case before a decision on the legal issues was reached.
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.
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 prosecutor called for prison terms of up to 15 months if found guilty. 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 Skyguide employees were cleared of any wrongdoing.
Murder of Peter Nielsen
Devastated by the loss of his wife and two children aboard flight 2937, Vitaly Kaloyev, a Russian architect, held Peter Nielsen responsible for their deaths. He tracked down and stabbed Nielsen to death, in the presence of his wife and three children, at his home in Kloten, near Zürich, on 24 February 2004. The Swiss police arrested Kaloyev at a local motel shortly after, and in 2005 he was sentenced to prison for the murder. He was released in November 2007 because his mental condition was not sufficiently considered in the initial sentence. In January 2008, he was appointed deputy construction minister of North Ossetia.
TCAS and conflicting orders
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 2] in Europe since 2000.[BFU 13] When the TCAS issues a resolution advisory (RA), 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. In responding to a TCAS RA that directs a deviation from assigned altitude, the flight crew should 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.
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 14] The manual described TCAS as "a backup to the ATC system", which could be wrongly interpreted to mean that ATC instructions have higher priority.[BFU 15] This ambiguity was replicated in the Tu-154 Flight Operations Manual, which contained contradictory sections. On the one hand, chapter 18.104.22.168 emphasized the role of the ATC and describes the TCAS as an "additional aid",[BFU 16] whilst chapter 22.214.171.124 forbade manoeuvers contrary to the TCAS.[BFU 17] 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 18]
Seventeen months before the Bashkirian Airlines-DHL collision there had already been another incident involving confusion between conflicting TCAS and ATC commands. In 2001 two Japanese airliners nearly collided with each other in Japanese skies. One of the 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 135 metres (443 ft), and the abrupt maneuver necessary to avert disaster left 100 occupants injured on one aircraft, some seriously.(pp2,176,134,22) In its report, published eleven days after the Überlingen accident, Japan called on the International Civil Aviation Organization (ICAO) to make it clear that TCAS advisories should always take precedence over ATC instructions. ICAO accepted this recommendation and amended its regulations in November 2003.
Before this accident a change proposal (CP 112) 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 19] 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 19] All TCAS II equipped aircraft have been upgraded to support RA reversal.
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 20][not in citation given]
Recommendations after the accident
The investigation report contains a number of recommendations concerning TCAS, calling for upgrades and for better training and clearer instructions to the pilots.[BFU 21]
Fourteen-year-old Kirill Degtyarev, a passenger on board Bashkirian Airlines Flight 2937, created paintings from age 4 and had held two public exhibitions. After his death two further exhibitions of his work were held, one in Ufa and one in Überlingen.
In popular culture
The Discovery Channel Canada / National Geographic TV series Mayday dramatized the accident in a Season 2 episode titled Deadly Crossroads (broadcast in some countries as Mid-Air Collision or A Father's Revenge). The accident was featured again during Mayday Season 8, in an episode titled System Breakdown.
"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.
- Test run reg: N3502P, Original registrations: 9J-AFO, VH-AWE and OO-DLK
- 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.
- "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.
- Gallagher, Paul (9 July 2002). "Jet pilot's 14 seconds dilemma before fatal crash". The Scotsman. Edinburgh. Archived from the original on 30 March 2005. Retrieved 18 January 2007.
- "Vain attempt to avert deadly crash". CNN. 2 July 2002. Archived from the original on 14 May 2010. Retrieved 9 April 2010.
- "Mid-air collision of 1 July 2002: sequence of events" (Skyguide). Archived 27 September 2011 at the Wayback Machine.
- "Passenger List". Archived from the original on 29 October 2008. Retrieved 21 November 2008.
- "Peter Nielsen stabbed to death," The Age February 29, 2004. May 6, 2008.
- Boyes, Roger (26 October 2005). "Father killed air traffic chief over fatal crash". The Sunday Times. London. Retrieved 28 December 2010.
- Wolfsteller, Pilar (26 October 2005). "Father 'saw black' as he killed air traffic controller". The Scotsman. Edinburgh. Retrieved 18 January 2007.[dead link]
- 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.
- 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.
- Wild, Matthew. "Family devastated by pilot's death". North Shore News. Archived from the original on 14 July 2011. Retrieved 18 January 2007.
- "Children's holiday party on doomed plane." CNN. 4 July 2002. Retrieved on 28 April 2010. Archived 12 May 2010 at the Wayback Machine.
- "В небе Германии столкнулись Ту-154 и Boeing 757: 71 человек погиб". www.newsru.com. Retrieved 2016-07-24.
- "Deadly Crossroads," Mayday
- "British pilot 'tried to avert disaster'". BBC. 2 July 2002. Archived from the original on 6 May 2008. Retrieved 8 April 2008.
- "Plane Crash Remembered; One Mourner Not Welcome". The New York Times. Retrieved 30 April 2006.
- "Appendices/Deviating positions for Investigation Report AX001-1-2/02 MAY 2004" (PDF). Retrieved 5 May 2008.
- "Air crash safety device switched off". BBC NEWS. 3 July 2002. Retrieved 14 July 2009.
- "Information regarding the air accident at Überlingen on 1 July 2002". Skyguide. Archived from the original on 10 November 2009. Retrieved 14 July 2009.
- "Plane crash killing trial starts". BBC News. 25 October 2005. Retrieved 8 April 2008.
- "Katastrophe von Überlingen – Flugunglück beschäftigt Landgericht". Stuttgarter Zeitung. 20 April 2008. Archived from the original on 21 April 2008. Retrieved 7 June 2009.
- Nils Köhler (23 August 2014). "12 Jahre nach dem Flugzeugunglück bei Überlingen: Wer verantwortet den Himmel über Südbaden?". Südkurier. Retrieved 18 July 2015.
- "Swiss go on trial over air crash". BBC. 15 May 2007. Retrieved 15 May 2007.
- "Four guilty over Swiss air crash". BBC. 4 September 2007. Retrieved 8 April 2008.
- "Swiss air crash controller killed." CNN. Wednesday 25 February 2004. Retrieved on 29 January 2010.
- Franchetti, Mark (10 February 2008). "Russia hails Vitaly Kaloyev a hero". The Sunday Times. London. Retrieved 8 September 2017.[dead link]
- "Introduction to TCAS II Version 7.1" (PDF). Federal Aviation Administration. Feb 28, 2011.
- "Aircraft Accident Investigation Report JAL907/JAL958" (PDF). Aircraft and Railway Accidents Investigation Commission. July 12, 2002. Retrieved 2015-10-31.
- Flight Safety Digest, March 2004
- Change proposal CP112E Archived 9 January 2009 at the Wayback Machine.
- "TCAS II Version 7.1 Requirements Coming to European Union". National Business Aviation Association. March 30, 2012. Retrieved 2015-02-22.
- "Deadly Crossroads". Mayday. Season 2. 2005. Discovery Channel Canada / National Geographic Channel.
- "System Breakdown". Mayday. Season 8. 2009. Discovery Channel Canada / National Geographic Channel.
- Flug in die Nacht – Das Unglück von Überlingen on IMDb
- Da Costa, Diego (June 24, 2015). "Arnold Schwarzenegger se convertirá en un padre vengativo en el drama '478' (Arnold Schwarzenegger will become a vengeful father in the drama '478')". ecartelera.com. Archived from the original on 1 Feb 2016. Retrieved June 23, 2015.
"Investigation Report AX001-1-2 (English)" (PDF). German Federal Bureau of Aircraft Accidents Investigation. 2 May 2004. Archived (PDF) from the original on 23 January 2007. Retrieved 17 January 2007.
- Section 1.1 "History of the flights", page 6
- Section 3.2 "Causes", page 110
- Section 4 "Safety Recommendations", pages 111–113
- Section 1.16.2 "ACAS/TCAS II analysis", page 34
- Section 2.7 "Analysis summary", pages 104–106
- Section 2.4.1 "ATC Zurich", page 76
- Section 1.12 "Wreckages and impacts information", pages 19–33
- Section 1.2 "Injuries to persons", page 9
- Section 1.17.1 "ATC Zurich", pages 35–42
- Section 126.96.36.199 "Warning systems", page 88
- page 89
- page 89
- page 45
- 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'."
- page 80 "The wording "TCAS is a backup to the ATC system..." could be interpreted that ATC takes priority to TCAS"
- 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
- page 103
- page 111 "Safety Recommendation 18/2003"
- page 35
- page 50
- Section 4 "Safety Recommendations", pages 111–113
|Wikimedia Commons has media related to Überlingen mid-air collision.|
- Final Report – German Federal Bureau of Aircraft Accidents Investigation (English)
- Final Report – German Federal Bureau of Aircraft Accidents Investigation (in German) – The German version is the version of record.
- "Information regarding the air accident at Überlingen on 1 July 2002." Skyguide.
- Davies, Barbara. "THE LOST CHILDREN; EXCLUSIVE Plane crash that robbed a Russian city of its youth." The Daily Mirror. July 13, 2002. – Includes partial victim list
- District Court of Konstanz Bashkirian Airlines v. Federal Republic of Germany (in German)
- Photo documentary from Owingen Fire Dept. (German) – Official website from Owingen Fire Dept. with photos from a firefighter's perspective
- Identifying the factors that contributed to the Ueberlingen mid-air collision (PDF 322 KB) – University of Illinois
- Gallery of crash victim Kyrill Degtyarev's works
- 'The Uberlingen mid-air collision: Lessons for the management of control rooms in the process industries', Loss Prevention Bulletin issue 196, 2007, IChemE, UK.
- 'Work Practice Simulation of Complex Human-Automation Systems: The Brahms Generalized Überlingen Model'