2002 Überlingen mid-air collision

On the night of 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, near the Swiss border. All 69 passengers and crew aboard the Tupolev and both crew members of the Boeing were killed.[4]

2002 Überlingen mid-air collision
Accident
Date1 July 2002 (2002-07)
SummaryCollision caused by Air Traffic Controller (ATC) confusion and compounded by ambiguity in Traffic Collision Avoidance System (TCAS) operation
SiteÜberlingen, Germany
47°46′42″N 9°10′26″E
Total fatalities71
Total survivors0
First aircraft

RA-85816, the Tu-154 involved in the accident, in July 1998, prior to its lease to Transeuropean Airlines.
TypeTupolev-Tu-154M
OperatorBashkirian Airlines
RegistrationRA-85816
Flight originDomodedovo International Airport, Moscow, Russia
DestinationBarcelona Int'l Airport, Barcelona, Spain
Passengers60
Crew9
Fatalities69
Survivors0
Second aircraft

A9C-DHL, the Boeing 757 involved in the accident, in August 1996.
TypeBoeing 757-23APF[1]
OperatorSNAS/DHL
RegistrationA9C-DHL [Note 1]
Flight originBahrain Int'l Airport, Manama, Bahrain[2][3]
StopoverOrio al Serio Airport, Bergamo, Italy
DestinationBrussels Airport, Brussels, Belgium
Passengers0
Crew2
Fatalities2
Survivors0

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 Controller (ATC) service in charge of the sector involved as well as ambiguities in the procedures regarding the use of Traffic Collision Avoidance System (TCAS), the on-board aircraft collision avoidance system.[5]:110[BFU 1]

A year and a half after the crash, on 24 February 2004, 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.[6][7][8][9]

Aircraft involved

Bashkirian Airlines Flight 2937 was a chartered flight from Moscow, Russia, to Barcelona, Spain, carrying 60 passengers and nine crew.[10] Forty-five of the passengers were Russian schoolchildren from the city of Ufa, in Bashkortostan, on a school trip organised by the local UNESCO committee to the Costa Dorada area of Spain.[11][2][12][13] Most of the parents of the children were high-ranking officials in Bashkortostan.[14] One of the fathers was the head of the local UNESCO committee.[15]

The aircraft, a 1995-built 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 (including 4,918 hours on the Tu-154) to his credit. Grigoriev, the chief pilot of Bashkirian Airlines, had 8,500 hours of flying experience (with 4,317 hours on the Tu-154) and his task was to evaluate Captain Gross's performance throughout the flight.[16]

41-year-old Murat Ahatovich Itkulov (Мурат Ахатович Иткулов), a seasoned pilot with close to 7,900 flight hours (with 4,181 of them on the Tu-154), who was normally the first officer, did not officially serve on duty, because this was the captain's assessment flight. 50-year-old Sergei Gennadyevich Kharlov (Сергей Геннадьевич Харлов), a flight navigator with approximately 13,000 flight hours (including 6,421 hours on the Tu-154), and 37-year-old Flight Engineer Oleg Irikovich Valeev (Олег Ирикович Валеев), who had almost 4,200 flight hours (all of which were on the Tu-154), joined the three pilots in the cockpit.[16]

DHL Flight 611, a Boeing 757-23APF cargo aircraft built in 1990 and registered as A9C-DHL, had originated in Bahrain and was being flown by two Bahrain-based[17][18] pilots, 47-year-old British Captain Paul Phillips and 34-year-old Canadian First Officer Brant Campioni.[19] Both pilots were very experienced — Phillips had logged close to 12,000 flight hours (including 4,145 hours on the Boeing 757) and Campioni had accumulated more than 6,600 flight hours, with 176 of them on the Boeing 757. At the time of the accident, the aircraft was en route from Bergamo, Italy, to Brussels, Belgium.

Accident
Site of the crash
The crash site, approximately 47° 46' 42″ N, 9° 10' 26″ E.
Skyguide Air Navigation Center Zürich in Wangen bei Dübendorf

The two aircraft were flying at flight level 360 (11,000 metres (36,000 ft)) 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.[10] Partly because of the added workload, and partly because of delayed radar data,[20] he did not realise the problem in time and thus failed to keep the aircraft at a safe distance from each other.[10]

Less than a minute before the accident he realised the danger and contacted Flight 2937, instructing the pilot to descend to flight level 350 to avoid collision with crossing traffic (Flight 611).[10] Seconds after the Russian crew initiated the descent, 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.[5]:111–113[BFU 2] Had both aircraft followed those automated instructions, the collision would not have occurred.[5]:34[BFU 3]

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 12 metres per second (2,400 ft/min), not quite as rapid as the 13 to 15 m/s (2,500 to 3,000 ft/min) range advised by that jet's TCAS; as for the Tupolev, the pilot disregarded his jet's TCAS instruction to climb, having already commenced his descent as instructed by the controller.[5]:104–106[BFU 4] 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).[5]:76[BFU 5]

Eight seconds before the collision, Flight 2937's crew finally realised their actual position when they gained visual sight of Flight 611 incoming from the left. Flight 611, in response, increased its descent rate.[5]:68–71[BFU 6][BFU 7] Two seconds before the collision, Flight 2937's pilots finally obeyed the jet's TCAS instruction to climb and attempted to put the aircraft into a climb, but the collision was now inevitable. The aircraft collided at 23:35:32 local time (21:35 UTC), at almost a right angle at an altitude of 10,630 metres (34,890 ft), with the Boeing's vertical stabiliser 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.[10]

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 stabiliser lost, struggled for a further 7 kilometres (4.3 mi; 3.8 nmi) 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.[5]:19–33[BFU 8] All 69 people on the Tupolev, and the 2 on board the Boeing, died.[5]:9[BFU 9][10]

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.[10] The other controller on duty was resting in another room for the night. This was against Skyguide's regulations but had been a common practice for years and was known and tolerated by management.[10] 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.[5]:35–42[BFU 10]

The ground-based optical collision warning system, which would have alerted the controller to the pending collision approximately 2​1⁄2 minutes before it happened,[5]:88[BFU 11] had been switched off for maintenance.[10] Nielsen was unaware of this.[5]:89 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 — however, whether or not this audible warning is functional is not something which is technically logged. Even if Nielsen had heard this warning, at that time finding a useful resolution order by the air traffic controller was impossible.[5]:89

Deviating statements in the official report
A temporary memorial at Überlingen's Sosa Fountain.

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.[21]

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.[21]

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 10,800 metres (35,500 ft) while the controller wrongly stated there was conflicting traffic above them at 11,000 metres (36,000 ft). Also, the controller gave the wrong position of the DHL plane (2 o'clock instead of the actual 10 o'clock).[22] 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.[21]

Switzerland notes that the Tupolev was about 33 metres (108 ft) below the flight level ordered by the Swiss controller, and still descending at 580 metres per minute (1,900 ft/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.[21]

Aftermath
A memorial plaque "Die zerrissene Perlenkette"
A memorial plaque
The Überlingen memorial
The Skyguide memorial to the aviation accident and murder of Peter Nielsen.

Nielsen needed medical attention due to traumatic stress caused by the accident.[23] At Skyguide, his former colleagues maintained a vase with a white rose over Nielsen's former workstation.[24] Skyguide, after initially having blamed the Russian pilot for the accident, accepted full responsibility and asked relatives of the victims for forgiveness.[25]

Skyguide paid compensation to the families of the dead children; the compensation amount was about CHF 30,000 ($34,087) to CHF 36,000. The Swiss Federal Court turned down appeals from some relatives for higher compensation in 2011.[26]

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,[27] but in late 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.[28]

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.[27]

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.[29] 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.[22] Another four Skyguide employees were cleared of any wrongdoing.[30]

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 personally responsible for their deaths.[22] He tracked down and stabbed Nielsen to death, in the presence of Nielsen's wife and three children, at his home in Kloten, near Zürich, on 24 February 2004.[24][31] The Swiss police arrested Kaloyev at a local motel shortly afterward, and in 2005 he was sentenced to prison for the murder.[32]

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.[32] In 2016, Kaloyev was awarded the highest state medal by the government, the medal "To the Glory of Ossetia".[22] The medal is awarded for the highest achievements, improving the living conditions of the inhabitants of the region, for educating the younger generation and maintaining law and order.[33]

TCAS and conflicting orders

The accident raised questions as to how pilots must react when they receive conflicting orders from 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.[5]:45 When 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 jeopardise 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.[34]

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.[34]

While 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.[5]:103[BFU 12] The manual described TCAS as "a backup to the ATC system", which could be wrongly interpreted to mean that ATC instructions have higher priority.[5]:80[BFU 13] This ambiguity was replicated in the Tu-154 Flight Operations Manual, which contained contradictory sections. On the one hand, chapter 8.18.3.4 emphasised the role of ATC and describes TCAS as an "additional aid",[5]:53[BFU 14] while chapter 8.18.3.2 forbade manoeuvers contrary to TCAS.[5]:103 The BFU recommended that this ambiguity should be resolved in favor of obeying TCAS advisories even when these were in conflict with ATC instructions.[5]:111[BFU 15]

Prior incident

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 airspace. One of the aircraft had received conflicting orders from TCAS and ATC; one pilot followed the instructions of 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 443 feet (135 m), and the abrupt maneuver necessary to avert disaster left 100 occupants injured on one aircraft, some seriously.[35](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.[36]

Technical solutions

Before this accident a change proposal (CP 112)[37] 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.[5]:35 According to an analysis by Eurocontrol this would have avoided the collision if the DHL crew had received and followed the new instructions and the Tupolev had continued to descend.[5]:35 All TCAS II equipped aircraft have been upgraded to support RA reversal.[38]

Additionally, an automatic downlink for 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.[5]:50

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.[5]:111–113[BFU 16] The TCAS II system was redesigned, with its ambiguous "Adjust Vertical Speed" RA voice command changed to "Level-Off", to increase proper responses from pilots.[39][40]

Films
  • The crash and the subsequent killing of the air traffic controller were used as the basis of a motion picture produced by German and Swiss TV stations SWR and SF, called Flug in die Nacht – Das Unglück von Überlingen (Flight into the night – the accident at Überlingen) (2009), starring Ken Duken as Nielsen and Evgeni Sitochin as Kaloyev.[41]
  • The U.S. film Aftermath (2017) is loosely based on the Überlingen mid-air collision, starring Arnold Schwarzenegger as a character largely based on Kaloyev.[42][43]
  • The Russian film Unforgiven (2018) is based on the Überlingen mid-air collision, with Dmitry Nagiyev portraying Kaloyev.[44]
Music
  • "Ballad of Vitaly", the closing track on the U.S. rock band Delta Spirit's album History from Below (2010), recounts the story of the mid-air collision and Vitaly Kaloyev's actions following the crash.[45]
  • The German futurepop band Edge of Dawn alludes to Kaloyev's story and mentions his name in the song "The Flight (Lux)", which appears on their EP The Flight (2005) and their full-length album Enjoy the Fall (2007).[46]
Podcasts
  • On 3 and 10 February 2019, Casefile True Crime Podcast: "Peter Nielsen", Case 106 (Parts 1 and 2) covered the story of the mid-air collision and subsequent killing of the former Skyguide air traffic controller Peter Nielsen, by the Russian architect, Vitaly Kaloyev.[47]
Television
  • The collision featured in multiple segments of the Canadian TV series Mayday:
    • "Deadly Crossroads", a Season 2 (2004)[16] (called Air Emergency and Air Disasters in the U.S. and Air Crash Investigation in the UK and elsewhere around the world). The dramatisation was broadcast in the United States with the title "A Father's Revenge"; and with the title "Mid-Air Collision" in the United Kingdom, Australia and Asia. Kaloyev was played by actor Kresimir Bosiljevac.
    • The flight was also included in a Mayday Season 8 (2009) Science of Disaster special titled "System Breakdown",[48] which looked at the role of air traffic controllers in aviation disasters.
  • The National Geographic Channel documentary series Seconds From Disaster featured this mid-air collision in the episode entitled "Collision at 35,000 feet", released on 26 September 2011.[49]
Theatre

In the U.S. off-Broadway play, My Eyes Went Dark, which opened 7 June 2017 and closed 2 July, playwright and director Matthew Wilkinson tells Kaloyev's story, which featured, among other characters, Declan Conlon as Kaloyev and Thusitha Jayasundera as his wife. It played at 59E59 Theaters in New York City.

See also

Notes
  1. Test run reg: N3502P, Original registrations: 9J-AFO, VH-AWE and OO-DLK
  2. 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.

References
  1. "A9C-DHL DHL International | DHX611 | Boeing 757-23APF – cn 24635 / ln 258". Planespotters.net. Archived from the original on 11 October 2008. Retrieved 6 September 2008.
  2. "Vain attempt to avert deadly crash". CNN. 2 July 2002. Archived from the original on 14 May 2010. Retrieved 9 April 2010.
  3. "Mid-air collision of 1 July 2002: sequence of events" (Skyguide). Archived 27 September 2011 at the Wayback Machine
  4. "Passenger List". aktuell.ru (in German). Archived from the original on 29 October 2008. Retrieved 21 November 2008.
  5. "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.
  6. Bott, Martin; Paterson, Tony (26 October 2005). "Father of air-crash victims guilty of revenge killing". The Independent. Independent Digital News & Media. Retrieved 4 November 2017.
  7. Boyes, Roger (26 October 2005). "Father killed air traffic chief over fatal crash". The Sunday Times. London. Retrieved 28 December 2010.
  8. 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.
  9. 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.
  10. "Case 106: Peter Nielsen (Part 1)". Casefile: True Crime Podcast. 2 February 2019.
  11. 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.
  12. Matsuura, Koïchiro (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). UNESCO| (12KiB). Retrieved 9 April 2010.
  13. Wild, Matthew. "Family devastated by pilot's death". North Shore News. Archived from the original on 14 July 2011. Retrieved 18 January 2007.
  14. "Children's holiday party on doomed plane." CNN. 4 July 2002. Retrieved on 28 April 2010. Archived 12 May 2010 at the Wayback Machine
  15. "В небе Германии столкнулись Ту-154 и Boeing 757: 71 человек погиб" [In the skies of Germany, Tu-154 and Boeing 757 collided: 71 people died]. www.newsru.com (in Russian). Retrieved 24 July 2016.
  16. "Deadly Crossroads". Mayday. Season 2. Episode 4. 2004. Discovery Channel Canada / National Geographic Channel.
  17. "Vain attempt to avert deadly crash". CNN. 2 July 2002. Archived from the original on 14 May 2010. Retrieved 9 April 2010.
  18. "British pilot 'tried to avert disaster'". BBC. 2 July 2002. Archived from the original on 6 May 2008. Retrieved 8 April 2008.
  19. Wild, Matthew. "Family devastated by pilot's death". North Shore News. Archived from the original on 14 July 2011. Retrieved 18 January 2007.
  20. "Plane Crash Remembered; One Mourner Not Welcome". The New York Times. Retrieved 30 April 2006.
  21. "Appendices/Deviating positions for Investigation Report AX001-1-2/02 MAY 2004" (PDF). Retrieved 5 May 2008.
  22. "Case 106: Peter Nielsen (Part 2)". Casefile: True Crime Podcast. 9 February 2019.
  23. "Air crash safety device switched off". BBC NEWS. 3 July 2002. Retrieved 14 July 2009.
  24. "Information regarding the air accident at Überlingen on 1 July 2002". Skyguide. Archived from the original on 10 November 2009. Retrieved 14 July 2009.
  25. "Plane crash killing trial starts". BBC News. 25 October 2005. Retrieved 8 April 2008.
  26. "Court upholds Skyguide compensation". SWI swissinfo.ch. Retrieved 19 September 2017.
  27. "Katastrophe von Überlingen – Flugunglück beschäftigt Landgericht" [Disaster of Überlingen – Flight accident employs district court]. stuttgarter-zeitung.de (in German). Stuttgarter Zeitung. 20 April 2008. Archived from the original on 21 April 2008.
  28. Köhler, Nils (23 August 2014). "12 Jahre nach dem Flugzeugunglück bei Überlingen: Wer verantwortet den Himmel über Südbaden?" [12 years after the aircraft accident near Überlingen: who is responsible for the skies over Südbaden?]. Südkurier (in German). Retrieved 18 July 2015.
  29. "Swiss go on trial over air crash". BBC. 15 May 2007. Retrieved 15 May 2007.
  30. "Four guilty over Swiss air crash". BBC News. BBC. 4 September 2007. Retrieved 8 April 2008.
  31. "Swiss air crash controller killed". CNN. 25 February 2004. Archived from the original on 26 February 2004. Retrieved 29 January 2010.
  32. Franchetti, Mark (10 February 2008). "Russia hails Vitaly Kaloyev a hero". The Sunday Times. London. Archived from the original on 8 September 2017.
  33. https://www.stav.kp.ru/daily/26487/3357178 Vitaly Kaloyev awarded with the medal "To the Glory of Ossetia" ALEXEY DROBOTOV
  34. "Introduction to TCAS II Version 7.1" (PDF). Federal Aviation Administration. 28 February 2011.
  35. "Aircraft Accident Investigation Report JAL907/JAL958" (PDF). Aircraft and Railway Accidents Investigation Commission. 12 July 2002. Retrieved 31 October 2015.
  36. Flight Safety Digest, March 2004
  37. Change proposal CP112E Archived 9 January 2009 at the Wayback Machine
  38. "TCAS II Version 7.1 Requirements Coming to European Union". National Business Aviation Association. 30 March 2012. Retrieved 22 February 2015.
  39. Decision criteria for regulatory measures on TCAS II version 7.1 Archived 12 June 2011 at the Wayback Machine
  40. Chludzinski, Barbara J. (29 April 2009). "Evaluation of TCAS II Version 7.1 Using the FAA Fast-Time Encounter Generator Model: Project Report ATC-346 Volume 1" (PDF). Lincoln Laboratory, Massachusetts Institute of Technology. p. iv.
  41. Flug in die Nacht – Das Unglück von Überlingen at IMDb
  42. Da Costa, Diego (24 June 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.
  43. Aftermath, retrieved 24 February 2019
  44. Unforgiven, retrieved 24 February 2019
  45. "The story of the Delta Spirit's murder ballad". Houston Chronicle. 14 July 2010. Retrieved 1 July 2020.
  46. "The Flight [Lux] - Edge Of Dawn". Genius.Com. Retrieved 1 July 2020.
  47. "Investigation Report of a Midair Collision near Überlingen" (PDF). www.bfu-web.de. 1 July 2002.
  48. "System Breakdown". Mayday. Season 8. Episode 1. 2009. Discovery Channel Canada / National Geographic Channel.
  49. Air Crash Disaster (11 February 2017), Air Crash Investigation DHL Flight 611 Deadly Mid Air Crash The Überlingen Disaster

Official report

"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.

  1. Section 3.2 "Causes", page 110
  2. Section 4 "Safety Recommendations", pages 111–113
  3. Section 1.16.2 "ACAS/TCAS II analysis", page 34
  4. Section 2.7 "Analysis summary", pages 104–106
  5. Section 2.4.1 "ATC Zurich", page 76
  6. Section 2.2.1 "Boeing B757-200", pages 68–69
  7. Section 2.2.2 "Tupolev TU154M", pages 69–71
  8. Section 1.12 "Wreckages and impacts information", pages 19–33
  9. Section 1.2 "Injuries to persons", page 9
  10. Section 1.17.1 "ATC Zurich", pages 35–42
  11. Section 2.6.1.4 "Warning systems", page 88
  12. 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'."
  13. page 80 "The wording "TCAS is a backup to the ATC system..." could be interpreted that ATC takes priority to TCAS"
  14. 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 that 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
  15. page 111 "Safety Recommendation 18/2003"
  16. Section 4 "Safety Recommendations", pages 111–113

On conflicting orders
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