Charkhi Dadri mid-air collision

Saudi Arabian Airlines Flight 763
Kazakhstan Airlines Flight 1907
Accident summary
Date	12 November 1996
Summary	Mid-air collision caused by pilot error on Kazakhstan Airlines aircraft
Site	Charkhi Dadri, Haryana, India
Total fatalities	349 (all)
Total survivors	0
First aircraft
HZ-AIA, a Saudi Arabian Airlines Boeing 747 identical to the aircraft involved in the collision.
Type	Boeing 747-100B
Operator	Saudi Arabian Airlines
Registration	HZ-AIH
Flight origin	Indira Gandhi Int'l Airport Delhi, India
Destination	Dhahran International Airport Dhahran, Saudi Arabia
Passengers	289
Crew	23
Fatalities	312 (all)
Survivors	0
Second aircraft
UN-76435, the Kazakhstan Airlines aircraft involved in the accident, in 1994.
Type	Ilyushin Il-76
Operator	Kazakhstan Airlines
Registration	UN-76435
Flight origin	Shymkent Int'l Airport
Destination	Indira Gandhi Int'l Airport
Passengers	27
Crew	10
Fatalities	37 (all)
Survivors	0

The Charkhi Dadri mid-air collision occurred on 12 November 1996 over the village of Charkhi Dadri, to the west of New Delhi, India. The aircraft involved were a Saudi Arabian Airlines Boeing 747-100B en route from Delhi to Dhahran, Saudi Arabia, and a Kazakhstan Airlines Ilyushin Il-76 en route from Chimkent, Kazakhstan, to Delhi. The crash killed all 349 people on board both planes, making it the world's deadliest mid-air collision,^[1]^[2] the deadliest aviation accident to occur in India,^[3] and the third-deadliest aircraft accident in the history of aviation, behind only the Tenerife airport disaster and Japan Airlines Flight 123.^[4]

Collision

The Saudi Arabian Airlines (Saudia) Boeing 747-168B, registration HZ-AIH,^[5] was due to operate the first leg of a scheduled international Delhi–Dhahran–Jeddah passenger service as Flight 763 (SVA763) with 312 occupants on board;^[6] the Kazakhstan Airlines Ilyushin Il-76TD,^[7] registration UN-76435, was on a charter service from Chimkent to Delhi as KZA1907.^[6] SVA763 departed Delhi at 18:32 local time.^[5] KZA1907 was, at the same time, descending to land at Delhi.^[6] Both flights were controlled by approach controller VK Dutta. The crew of SVA763 consisted of Captain Khalid Al Shubaily, First Officer Nazir Khan, and Flight Engineer Edris.^[8] On KZA1907, Gennadi Cherepanov served as the pilot and Egor Repp served as the radio operator.^[9]

KZA1907 was cleared to descend to 15,000 feet (4,600 m) when it was 74 nautical miles (137 km) from the beacon of the destination airport while SVA763, travelling on the same airway as KZA1907 but in the opposite direction, was cleared to climb to 14,000 feet (4,300 m). About eight minutes later, around 18:40, KZA1907 reported having reached its assigned altitude of 15,000 feet (4,600 m) but it was actually lower, at 14,500 feet (4,400 m), and still descending.^[7] At this time, Dutta advised the flight, "Identified traffic 12 o'clock, reciprocal Saudia Boeing 747, 10 nautical miles (19 km). Report in sight."

When the controller called KZA1907 again, he received no reply. He warned of the other flight's distance, but it was too late. The two aircraft had collided, the tail of KZA1907 cut through SVA763's left wing and horizontal stabiliser. The crippled Boeing quickly lost control and went into a rapidly descending spiral motion toward the ground with fire trailing from the wing. The Boeing broke up in the air under the stresses before the wreckage hit the ground at almost 1,135 km/h (705 mph). The Ilyushin remained structurally intact as it went in a steady but rapid and uncontrolled descent until it crashed in a field.^[10] Rescuers discovered four critically injured passengers from the Ilyushin, but they all died soon afterwards. Two passengers from the Saudia flight survived the crash, still strapped to their seats, only to die of internal injuries soon after.^[11]^[12] In the end, all 312 people on board SVA763 and all 37 people on KZA1907 were killed.

Captain Timothy J. Place, a pilot for the United States Air Force, was the sole eyewitness to the event. He was making an initial approach in a Lockheed C-141B Starlifter when he saw that "a large cloud lit up with an orange glow".^[13]

The collision took place about 100 kilometres (60 mi) west of Delhi.^[14] The wreckage of the Saudi aircraft crashed near Dhani village, Bhiwani District, Haryana. The wreckage of the Kazakh aircraft hit the ground near Birohar village, Rohtak District, Haryana.^[15] This was the first mid-air collision between two commercial aircraft since the Dniprodzerzhynsk mid-air collision in 1979;^[6] it was succeeded by the mid-air collision between a Bashkirian Airlines Tupolev Tu-154M and a DHL Boeing 757 over Germany in July 2002 (2002-07)^[16] and then by the mid-air collision between a Gol Boeing 737 and an ExcelAire Embraer Legacy over Amazonia in September 2006 (2006-09).^[17]

Passengers and crews

Saudi Arabian Airlines Flight 763

The captain of the flight, aged 45, was a veteran pilot with more than 9,800 flying hours to his credit.^[15] An article published in The New York Times on 14 November 1996 stated that 215 Indians who boarded the flight worked in Saudi Arabia;^[18] many of them worked or planned to work in blue collar jobs^[19] as house maids, drivers, and cooks. The article also stated that 40 Nepalis and three Americans boarded the Saudi flight.^[18] According to an article in the same newspaper published a day earlier, the passenger manifest included 17 people of other nationalities, including nine Nepalis, three Pakistanis, two Americans, one Bangladeshi, one Briton, and one Saudi.^[4] Twelve of the crew members, including five anti-terrorism officials, were Saudi citizens.^[20]

Kazakhstan Airlines Flight 1907

The 44-year-old captain of Flight 1907 was also highly experienced, with more than 9,200 flight hours under his belt.^[15] A company from Kyrgyzstan chartered the flight, and the passenger manifest mostly included ethnic Russian Kyrgyz citizens planning to go shopping in India.^[4]^[9]^[18]

Thirteen Kyrgyz traders boarded the flight.^[20]

Investigation and final report

The crash was investigated by the Lahoti Commission, headed by then-Delhi High Court judge Ramesh Chandra Lahoti. Depositions were taken from the Air Traffic Controllers Guild and the two airlines. The flight data recorders were decoded by Kazakhstan Airlines and Saudia under the supervision of air crash investigators in Moscow and Farnborough, England, respectively.^[10] The ultimate cause was held to be the failure of Kazakhstan Airlines Flight 1907's pilot to follow ATC instructions, whether due to cloud turbulence or due to communication problems.

The commission determined that the accident had been the fault of the Kazakh Il-76 commander, who (according to FDR evidence) had descended from the assigned altitude of 15,000 to 14,500 feet (4,600 to 4,400 m) and subsequently 14,000 feet (4,300 m) and even lower. The report ascribed the cause of this serious breach in operating procedure to the lack of English language skills on the part of the Kazakh aircraft pilots; they were relying entirely on their radio operator for communications with the ATC. The radio operator did not have his own flight instrumentation but had to look over the pilots' shoulders for a reading.^[21] Kazakh officials stated that the aircraft had descended while their pilots were fighting turbulence inside a bank of cumulus clouds.

Indian air controllers also complained that the Kazakh pilots sometimes confused their calculations because they are accustomed to using metre altitudes and kilometre distances, while most other countries use nautical miles and feet.^[11]

Just a few seconds from impact, the Kazakh plane climbed slightly and the two planes collided. This was because the radio operator of Kazakhstan 1907 discovered only then that they were not at 15,000 feet and asked the pilot to climb. The captain gave orders for full throttle, and the plane climbed, only to hit the oncoming Saudi plane. The tail of the Kazakh plane clipped the left wing of the Saudi jet, severing both parts from their respective planes. Had the Kazakh pilots not climbed slightly, it is likely that they would have passed under the Saudi plane.

The recorder of the Saudi plane revealed the pilots recited the prayer that is required, according to Islamic law, when one faces death. The counsel for the ATC Guild denied the presence of turbulence, quoting meteorological reports, but did state that the collision occurred inside a cloud.^[21] This was substantiated by the affidavit of Capt. Place, who was the commander of the aforementioned Lockheed C-141B Starlifter, which was flying into New Delhi at the time of the crash.^[10] The members of his crew filed similar affidavits.^[22]

Furthermore, Indira Gandhi International Airport did not have secondary surveillance radar, which provides extra information, such as the aircraft's identity and altitude, by reading transponder signals; instead the airport had primary radar, which produces readings of distance and bearing, but not altitude. In addition, the civilian airspace around New Delhi had one corridor for departures and arrivals. Most areas separate departures and arrivals into separate corridors. The airspace had one civilian corridor because much of the airspace was taken by the Indian Air Force.^[10] Due to the crash, the air-crash investigation report recommended changes to air-traffic procedures and infrastructure in New Delhi's air-space:

Separation of inbound and outbound aircraft through the creation of 'air corridors'
Installation of a secondary air-traffic control radar for aircraft altitude data
Mandatory collision avoidance equipment on commercial aircraft operating in Indian airspace
Reduction of the airspace over New Delhi that was formerly under exclusive control of the Indian Air Force

The Civil Aviation Authorities in India made it mandatory for all aircraft flying in and out of India to be equipped with an Airborne collision avoidance system.

Disaster in popular media

Miditech, a company based in Gurgaon, Haryana, produced a documentary about the disaster called Head On!, which aired on the National Geographic Channel.^[10]

The disaster was again the subject of an episode in the documentary series Mayday (Air Crash Investigation) on 2 March 2009 entitled "Sight Unseen", in a wide-screen format with sophisticated computer animations on National Geographic Channel.^[23]