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2002 Überlingen mid-air collision

Coordinates: 47°46′42″N 9°10′26″E / 47.77833°N 9.17389°E / 47.77833; 9.17389
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Bashkirian Airlines Flight 2937
DHL Flight 611
Occurrence
Date1 July 2002
SummaryMid-air collision
involving ATC error
SiteÜberlingen, Germany
47°46′42″N 9°10′26″E / 47.77833°N 9.17389°E / 47.77833; 9.17389
Total fatalities71
Total survivors0
First aircraft
TypeTupolev Tu-154M
OperatorBashkirian Airlines
RegistrationRA-85816disaster
Flight originDomodedovo Int Airport[2][3]
 Moscow, Russia
DestinationBarcelona Int'l Airport
 Barcelona, Spain
Passengers60
Crew9
Second aircraft
TypeBoeing 757-23APF[1]
OperatorDHL Aviation
RegistrationA9C-DHLdisaster
Flight originBahrain Int'l Airport[4][5]
StopoverOrio al Serio Airport
 Bergamo, Italy
DestinationBrussels Airport, Belgium
Passengers0
Crew2
Site of the crash is located in Germany
Site of the crash
Site of the crash
Site of the crash (Germany)

Bashkirian Airlines Flight 2937, registration RA-85816, was a Tupolev 154M passenger jet en route from Moscow, Russia, to Barcelona, Spain. DHL Flight 611, registration A9C-DHL, was a Boeing 757-23APF cargo jet flying from Bergamo, Italy, to Brussels, Belgium. The two aircraft collided in mid-air on 1 July 2002, at 21:35 (UTC) over the towns of Owingen and Überlingen in Germany, (near Lake Constance), killing all 71 aboard both aircraft. German official investigators determined on 19 May 2004, that the accident had been caused by problems within the air traffic control system and problems with the use of the collision warning system.[2] On 24 February 2004, the controller who was on duty at the time, Dane Peter Nielsen, was stabbed to death by Vitaly Kaloyev[6] who had lost his wife and two children in the accident.[7][8]

The flights involved

Flight 2937 was a chartered flight carrying 60 passengers and 9 crew. 45 of the passengers were Bashkortostan schoolchildren being taken to a resort in the Costa Dorada area of Spain[4] as a prize for their win in republican competitions.[3][9] They took a train from Ufa to Moscow.[10] Most of the parents of the children were high-ranking officials in Bashkortostan[11]. A local committee for UNESCO organized the holiday trip.[12] Originally the children were supposed to leave from Sheremetyevo Airport on a Sunday; the children had arrived late in Moscow and they had arrived at the wrong airport.[10] The children did not leave until Monday (1 July)[11] from Domodedovo International Airport. A Russian crew operated the aircraft. The captain, Alexander Mihailovich Gross (Александр Михайлович Гросс)[10], and the first officer and Alexander Gross's supervisor, Oleg Pavlovich Grigoriev (Олег Павлович Григорьев)[10], flew the Tupolev. Oleg Grigoriev, the chief pilot of Bashkirian Airlines, used the trip to evaluate Gross's performance. Murat Ahatovich Itkulov (Мурат Ахатович Иткулов)[10], normally the first officer, did not officially serve on duty because Grigoriev sat in his seat. The crew wanted the opinions and guidance of Murat Itkulov, who was slated to be promoted to captain. Sergei Kharlov, a navigator, and a flight engineer joined the three pilots.[10]

Flight 611 was carrying a load of air freight and had two Bahrain-based[13][4] crew members aboard, British Captain Paul Phillips and Canadian First Officer Brant Campioni.[9]

Notable passengers on Flight 2937

14-year old Kirill Degtyarev created paintings from age 4 to his death and held two public exhibitions before his death. After his death, Ufa hosted one exhibition and Überlingen hosted another exhibition.[10]

The accident

File:Uberlingen aircraft accident computer reconstruction.jpg
Computer reconstruction of the accident derived from the Flight Data Recorder and collision evidence.
File:Uberlingen aircraft accident computer reconstruction side view.jpg
Computer reconstruction (side view).

The two aircraft were flying at flight level 360 (approximately 36,000 feet above Mean Sea Level) on a collision course. Despite being over Germany, the airspace was controlled from Zürich, Switzerland by the private Swiss airspace control company Skyguide.

The air traffic controller handling the airspace, Peter Nielsen, was working two workstations at the same time and did not realise the danger facing the two aircraft until less than a minute before the accident. At that time he 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. Had both aircraft followed those automated instructions, it is likely that the collision would not have occurred.

Flight 611's pilots on the Boeing jet initially followed the TCAS instructions and initiated a descent, but could not immediately inform the controller due to the fact that he was dealing with Flight 2937. About eight seconds before the collision, Flight 611's descent rate was about 2400 feet per minute, not as rapid as the 2500-3000 ft/min range advised by TCAS. The Russian pilot on the Tupolev disregarded the TCAS instruction to climb and instead began to descend, as instructed by the controller, 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.

The aircraft collided at almost a right angle at an altitude of 34,890 feet, 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 continued, stalled, and fell. The crippled Boeing, now with 80% of its vertical stabilizer lost, struggled for a further seven kilometres (4.3 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.

Other factors in the crash

One air traffic controller, Peter Nielsen of ACC Zurich, was controlling the airspace through which the aircraft were transitioning. The only 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. Due to maintenance work, Nielsen had a stand-by controller and system manager on call. Nielsen was either unaware of this or he chose not to use either of the two additional air traffic controllers available to him.[2] When Nielsen realised that the situation had subtly increased beyond his span of control, it was too late to summon assistance.

In the minutes before the accident, Nielsen was occupied with an Airbus on a delayed Aero Lloyd Flight 1137 approaching Friedrichshafen Airport.[2] Handling two workstations at once, Nielsen struggled with the malfunctioning phone system that he was trying to use to call the Friedrichshafen airport to announce the approaching Aero Lloyd. Due to these distractions he did not spot the danger until about a minute before impact. Had he ordered the Russian plane to descend earlier, the aircraft would have been separated and their collision avoidance systems would not have issued instructions. Additionally, after Nielsen instructed the Russian crew to descend, he returned to the situation with the Airbus bound for Friedrichshafen, and did not hear the DHL aircraft TCAS report of it's descent.

Another factor was 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; if this audible warning is turned on or not, is not logged technically. Even if Nielsen had heard this warning, he might have misinterpreted it until the next radar update 12 seconds later became visible or until the TCAS descent notice by the DHL crew came in; at that time finding a useful resolution order by the air traffic controller is difficult to impossible.[2]

The main phone lines at Skyguide was also down as part of the maintenance work, and the backup line was defective. This caused Nielsen to spend more time than he anticipated coordinating the Airbus late arrival into Friedrichshafen than he anticipated, causing him to miss several calls from aircraft. The faulty phone lines also prevented adjacent air traffic controllers at Karlsruhe from phoning in a warning.

Investigation

The accident was investigated by the German Bundesstelle für Flugunfalluntersuchung (BFU), which published its report in May 2004. The BFU identified two "immediate" causes of the accident and three "systemic" causes.

Immediate causes

  • The imminent separation infringement was not noticed by ATC in time. The instruction for the TU154M to descend was given at a time when the prescribed separation could not be ensured any more.
  • The TU154M crew followed the ATC instruction to descend and continued to do so even after TCAS advised them to climb. The manouvre was performed contrary to the TCAS advice.


Systemic causes

  • The integration of ACAS/TCAS II into the system aviation was insufficient and did not correspond in all points with the system philosophy. The regulations concerning ACAS/TCAS published by ICAO ... were not standardised, incomplete and partially contradictory.
  • Management and quality assurance of the air navigation service company did not ensure that during the night all open workstations were continually staffed by controllers.
  • Management and quality assurance of the air navigation service company tolerated for years that during times of low traffic flow at night only one controller worked and the other one retired to rest.

The BFU report contained nineteen safety recommendations.

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 comments were published as an appendix to the report but not commented by the German federal investigators[14].

The Kingdom of Bahrain, as the home country of the DHL plane, mostly agrees with the findings of the report. They say 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.

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 wrongfully 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.

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.

The change of magnetic bearing of the Russian aircraft by cumulatively 20 degrees (from 254 to 274) during the upcoming conflict is not assessed in the official report.

Failure to learn from prior incident

The International Civil Aviation Organization (ICAO) did not take proper lessons from the near-miss which occurred about a year before the Bashkirian-DHL collision.[15] During the 2001 Japan Airlines mid-air incident, two Japanese airliners, both Japan Airlines, nearly collided with each other in Japanese skies. Disaster was avoided because one of the pilots made evasive manoeuvres based on a visual judgement, and 677 people were saved. If the collision had occurred, it would have been the deadliest civil aviation accident in terms of passenger lives. The aircraft missed each other by less than 100 metres, and the abrupt manoeuver necessary to avert disaster left about 100 occupants hurt on one aircraft, some seriously. Japanese authorities called for measures that would prevent similar accidents from happening, but ICAO did not further investigate the incident until after the Germany collision. In addition four near misses in Europe occurred before the Germany disaster because one set of pilots obeyed the air traffic controllers instead of the TCASs. The ICAO decided to fulfill Japan's request 18 months after the Japan Airlines incident.[10]

Consequences

Nielsen had retired from his job as controller after the accident, since he had been struck by grief and guilt over the incident. At Skyguide, his former colleagues maintain to this day a vase with a white rose over Nielsen's former workstation. Skyguide, after initially having blamed the Russian pilot for the accident, accepted its part of the responsibility and paid compensation to some of the Russian families.

On 19 May 2004, the official investigators found that managerial incompetence and systems failures were the main cause for the accident, so that Nielsen was surely not the only one to be blamed for the disaster. As explained above, a series of coincidences of which Kaloyev and Nielsen were unaware precipitated the accident.

On 27 July 2006, the court of Konstanz determined that fault lay exclusively with the German government, since it was against German law to allow Skyguide to offer air traffic control services in German airspace. The government's appeal is currently pending.

A criminal investigation of the Skyguide begun as of May 2004. On 7 August 2006, a Swiss prosecutor filed manslaughter charges against eight employees of Skyguide. The Winterthur prosecutor called for jail terms of six to 15 months, alleging "homicide by negligence".[16] 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.[17]

Murder of Peter Nielsen

Main article: Vitaly Kaloyev

Grieved by the loss of his family, Vitaly Kaloyev held Peter Nielsen responsible for their deaths. He killed Nielsen at his Kloten home,[18] near Zürich, on 24 February 2004.[19] 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.

Conflicting orders

According to the section on TCAS operations in the flight operations manual: If an instruction to manoeuvre is received simultaneously from an RA (resolution advisories, i.e. the TCAS) and from ATC, the advice given by RA should be followed.

It is not required to notify the ATC prior to responding to an RA. This manoeuvre does not require any ATC clearance since TCAS takes into account the position of all other aircraft with transponders in the surrounding area.

The pilot, while seemingly following the section of Tu-154 Flight Operations Manual (in Russian), which states according to the official investigation report (page 80): 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., completely disregarded a more strict and clear requirement of the manual, which prohibited him from performing commands opposite RA recommendations („Запрещается выполнять команды противоположные тем, которые выдает система.“, pp. 71 and 106 of the English version of the investigation report).

Before this accident a change proposal (CP 112) for the TCAS II system has been issued. This proposal would have created a "reversal" of the original warning - asking the DHL plane to climb and the Tupolev crew to sink. 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 sink.[2]

Dramatization

This accident was featured in an episode of the Discovery Channel Canada program Mayday (also known as Air Emergency on the National Geographic Channel in the US or Air Crash Investigation in other parts of the world).

References

  1. ^ "A9C-DHL DHL International Boeing 757-23APF - cn 24635 / ln 258 - Planespotters.net". planespotters.net. Retrieved 2008-09-06.
  2. ^ a b c d e f "Investigation Report AX001-1-2/02 MAY 2004" (PDF). Retrieved 2007-01-17.
  3. ^ a b Gallagher, Paul. "Jet pilot's 14 seconds dilemma before fatal crash". scotsman.com. Retrieved 2007-01-18.
  4. ^ a b c "Vain attempt to avert deadly crash, CNN
  5. ^ "Mid-air collision of 1 July 2002: sequence of events" (Skyguide).
  6. ^ "Swiss law court decided to free V.Kaloyeva"
  7. ^ Wolfsteller, Pilar. "Father 'saw black' as he killed air traffic controller". scotsman.com. Retrieved 2007-01-18.
  8. ^ "Nothing left to lose: grief-crazed murder suspect haunted by family's air deaths," The Guardian
  9. ^ a b Wild, Matthew. "Family devastated by pilot's death". north shore news. Retrieved 2007-01-18.
  10. ^ a b c d e f g h "Deadly Crossroads," Mayday
  11. ^ a b "Children's holiday party on doomed plane," CNN
  12. ^ "Address by Mr Koïchiro Matsuura," UNESCO
  13. ^ "British pilot 'tried to avert disaster'," BBC
  14. ^ "Appendices/Deviating positions for Investigation Report AX001-1-2/02 MAY 2004" (PDF). Retrieved 2008-05-05.
  15. ^ "report outline". ICAO. Retrieved 2007-01-22.
  16. ^ Swiss go on trial over air crash - BBC News Online - Retrieved on 15 May 2007
  17. ^ "Four guilty over Swiss air crash," BBC
  18. ^ "Swiss air crash controller killed," CNN
  19. ^ "Skyguide - information regarding the air accident". Retrieved 2007-01-18.

Official releases

Press

On conflicting orders

Skyguide

Camphill School

Other

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