Bashkirian Airlines Flight 2937

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Bashkirian Airlines Flight 2937
DHL Flight 611

Tail of Bashkirian Tu-154 smouldering in Germany.
Summary
Date   1 July 2002
Type   Mid-air collision
Site   Überlingen, Germany
Fatal Injuries   71
Serious Injuries   0
Aircraft 1
Aircraft type   Tupolev 154M
Operator   Bashkirian Airlines
Registration   RA-85816
Passengers   60
Crew   9
Survivors   0
Aircraft 2
Aircraft type   Boeing 757-200
Operator   DHL
Registration   A9C-DHL
Passengers   0
Crew   2
Survivors   0

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 757-200 cargo jet flying from Bergamo, Italy to Brussels, Belgium. The two aircraft collided in mid-air on July 1, 2002 at 21:35 (UTC) over Überlingen, Germany (near Lake Constance), killing all 71 aboard both aircraft. German official investigators determined on May 19, 2004 that the accident had been caused by problems within the air traffic control system[1]; and on February 24, 2004 the controller who was on duty at the time, Peter Nielsen, was stabbed to death by an architect who lost his wife and both of his children in the accident.[2]

Contents

[edit] The flights involved

Flight 2937 was a chartered airliner carrying 60 passengers and 9 crew. 45 of the passengers were Russian children being taken to a resort in Spain.[3][4]

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

[edit] The accident

Computer reconstruction of the accident derived from the Flight Data Recorder and collision evidence
Computer reconstruction of the accident derived from the Flight Data Recorder and collision evidence
Computer reconstruction (side view)
Computer reconstruction (side view)

The two aircraft were flying at 36,000 (FL360) feet 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 unlikely that the collision would 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. During this descent the Russian pilot went below his assigned flight level by about 33 metres (110 feet), and also changed his magnetic bearing once again, by another ten degrees.

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 other plane. Maintenance work was being carried out on the main radar system, which meant that the controllers were forced to use a slower system. Precious seconds were lost as the Flight 2937 crew tried to locate the DHL flight visually in the dark.

The aircraft collided at almost a right angle at 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 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, were killed.

[edit] Other factors in the crash

Only a single 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 unaware of this or he chose not to use them in order to avoid dangerous boredom.

In addition, a 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 acoustical warning is turned on or not, is not protocoled 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[1].

The main phone lines at Skyguide was also down as part of the maintenance work, and the backup line was defective. This prevented adjacent air traffic controllers at Karlsruhe from phoning in a warning.

In the minutes before the accident, Nielsen was occupied with a delayed Aero Lloyd flight approaching Friedrichshafen Airport[1]. He had to handle two workstations at once and was struggling 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. When Nielsen realized that the situation (the multiple factors in two workstations) was overwhelming, it was too late to summon assistance.

Switzerland commented in the "Publication of deviating statements" section of the official report of the German federal investigators that the Tupolev was about 33 metres below the flight level ordered by the Swiss controller, and still descending at 1900 feet per minute, and 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 Russian Federation countered in the same section of the official report 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), and 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.

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.

[edit] Mixed messages in prior incident

No proper lessons had been taken from a near-miss which occurred about a year before the Bashkirian-DHL collision[5]. Two Japanese airliners, both Japan Air, nearly collided with each other in Japanese skies. The two planes were on a collision course and the pilots of both planes had received conflicting instructions from their TCAS and the flight controller. Disaster was avoided because both pilots, each unaware of the other's decision, followed the TCAS instructions, ignoring the controller's orders. Even so, they missed each other by less than 100 metres, and the abrupt manoeuvres that were necessary to avert disaster left about 100 passengers hurt, some seriously. Japanese authorities called for measures that would prevent similar accidents from happening, but they were ignored.

[edit] Consequences

Peter Nielsen was stabbed to death in front of his home in Zürich on February 24, 2004[6]. A Russian man, Vitaly Kaloyev, was arrested within a few days. Kaloyev had lost his wife and both of his children; the three had been aboard Flight 2937. He is reported to have suffered a nervous breakdown following the loss of his entire family, especially since he was one of the first relatives to arrive at the crash site. Kaloyev participated in the search for the bodies and, tragically enough, located his own daughter's body, which was surprisingly intact (unlike his wife's and son's, which were found days later, mutilated by the force of the crash). Kaloyev spent the first year after the accident lingering at the graves of his family, and on the memorial service for the first anniversary of the tragedy he asked the head of Skyguide about the possibility of meeting the controller who had been responsible for the disaster. He was ignored. After travelling to Zurich and stabbing Nielsen, Kaloyev was found in his hotel room, apparently in shock. He claimed having no memory of what he had done and was taken to a mental hospital, where he was evaluated to determine if he was fit to stand trial.

Answering questions from the judge, Vitaly Kaloyev said that the plane crash above Lake Constance had put an end to his life. He said that his children were the youngest on board Flight 2937, so there was no need for him to identify the bodies. Kaloyev said that he was crushed by the loss of his family: "I have been living on the cemetery for almost two years, sitting behind their graves," he said.

Kaloyev presented a document received from a law firm in Hamburg dated 11 November 2003. It was an amicable agreement in which Skyguide offered Kaloyev 60,000 Swiss francs for the death of his wife and 50,000 francs for the death of each of his two children. In return, Skyguide asked Vitaly Kaloyev to decline any claims to the company. The document infuriated the man: he decided to meet the company's Director Alan Rossier and flight control officer Peter Nielsen in person.

"Apparently he did not expect that he would have to answer for the results of his work", Kaloyev said. "He murmured something to me. Then I showed him some pictures of my children and said: 'They were my children. What would you feel if you saw your children in coffins?' I was infuriated about Skyguide's initiative to haggle over my dead children," the man said.

Vitaly Kaloyev said that he wanted Peter Nielsen to apologise to him for the death of his family. "He hit me on the hand, when I was holding the envelope with the photographs of my children. I only remember that I had a very disturbing feeling, as if the bodies of my children were turning over in their graves," said he. The man added that he did not remember what he did afterwards.

On October 26, 2005, Kaloyev was sentenced to eight years in prison. Kaloyev remains incarcerated in Switzerland; taking into account his 610 days incarceration before the sentence, he should be freed in 2011.[7]

On May 19, 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.

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 responsibility and has paid compensation to some of the Russian families.

On July 27, 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.

A criminal investigation of the Skyguide begun as of May 2004. On August 7, 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".

[edit] 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.

However, the pilot was following the 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.

Before this accident a change proposal (CP 112) for the TCAS II system has been issued. This proposal would have avoided this accident by a reversal resolution advisory.

[edit] References

  1. ^ a b c Investigation Report AX001-1-2/02 MAY 2004. Retrieved on 2007-01-17.
  2. ^ Wolfsteller, Pilar. Father 'saw black' as he killed air traffic controller. scotsman.com. Retrieved on 2007-01-18.
  3. ^ Gallagher, Paul. Jet pilot's 14 seconds dilemma before fatal crash. scotsman.com. Retrieved on 2007-01-18.
  4. ^ a b Wild, Matthew. Family devastated by pilot's death. north shore news. Retrieved on 2007-01-18.
  5. ^ report outline. ICAO. Retrieved on 2007-01-22.
  6. ^ Skyguide - information regarding the air accident. Retrieved on 2007-01-18.
  7. ^ Father jailed for air traffic murder. scotsman.com. Retrieved on 2007-10-18.

[edit] External links

[edit] Official releases

[edit] Press

[edit] On conflicting orders

[edit] Skyguide

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