1996 Charkhi Dadri mid-air collision

SVA Flight 763 departed Delhi at 18:32 local time (13:02 UTC). KZA Flight 1907 was descending simultaneously, to land at Delhi.[5] Both flights were controlled by approach controller V.K. Dutta.[10] Immediately after take-off, the SVA flight was cleared to an initial altitude of 10,000 feet (3,050 m). At 18:34, Dutta cleared the KZA plane to descend to 15,000 feet (4,550 m) when it was 74 nautical miles (137 km) from the beacon of the destination airport. Two minutes later, at 18:36, Dutta cleared the SVA plane, travelling on the same airway but in the opposite direction, to climb to 14,000 feet (4,250 m). At 18:38, the SVA crew reported reaching 14,000 feet, and requested a higher level. Dutta told them to hold their altitude and standby, to which First Officer Khan replied, "Saudi 763 will maintain one four zero."[10]

At 18:39, the KZA flight reported having reached its assigned altitude of 15,000 feet, but it was actually higher, at 16,348 feet (5,000 m), and still descending.[11][10] At this time, Dutta advised the flight, "Identified traffic 12 O'Clock, reciprocal, Saudia Boeing 747 at ten miles, likely to cross in another five miles. Report, if in sight."[10] Radio Operator Repp requested clarification, to which Dutta replied, "Traffic...is at eight miles, level 140."[10] Repp acknowledged the update, and signed off with, "Now looking 1907."[10]

Less than a minute later, at 18.40, a USAF cargo flight on its descent called in to say they had seen "a big explosion" at their two o'clock position.[10] Dutta attempted to contact the SVA and KZA flights, but received no response. The two aircraft had collided, with the left wing of the KZA flight slicing through the left wing of the SVA 747 while the left horizontal stabiliser of the 747 sliced off the vertical stabilizer (including the horizontal stabilizer) of the KZA flight.[12] The crippled Saudi Boeing quickly lost control and went into a rapidly descending spiral with fire trailing from the wing, and the aircraft broke up in mid air before crashing into the ground at a nearly supersonic speed of 1,135 km/h (613 kn; 705 mph). With most of its left wing and vertical stabilizer gone, the Ilyushin went into a flat spin and crashed into a field at a flat attitude near the wreckage of the Saudia plane. All 312 people on board SVA763 and all 37 people on KZA1907 were killed.[12][13]

The collision took place about 100 kilometres (60 mi) west of Delhi.[14] The wreckage of the Saudi Arabian aircraft landed near Dhani village, Bhiwani District, Haryana. The wreckage of the Kazakh aircraft hit the ground near Birohar village, Rohtak District, Haryana.[6]

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.[15] 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.[10][16][17][18]

The commission determined that the accident had been the fault of the Kazakhstani Il-76 crew, who (according to FDR evidence) had descended from the assigned altitude of 15,000 to 14,500 feet (4,550 to 4,400 m) and subsequently 14,000 feet (4,250 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 Kazakhstan aircraft pilots; they were relying entirely on Radio Operator Repp for communications with the ATC. As part of this, the report suggested that First Officer Dzhangirov (and possibly Captain Cherepanov) might have misunderstood Dutta's final radio call, and assumed that the Saudi 747's altitude (14,000 feet) was their own assigned altitude.[10] Furthermore, Repp did not have his own flight instrumentation and had to look over the pilots' shoulders for a reading, which likely limited his own situational awareness.[19] Kazakh officials stated that the aircraft had descended while their pilots were fighting turbulence inside a bank of cumulus clouds.[10][17]

Indian air controllers also complained that the Kazakhstani pilots sometimes confused their calculations because they are accustomed to using metre altitudes and kilometre distances, while most other countries use feet and nautical miles respectively for aerial navigation.[20]

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

The recorder of the Saudi Arabian plane revealed the pilots said the Islamic Istighfar and recited the Shahada before impact with the ground.[21] The counsel for the ATC Guild denied the presence of turbulence, quoting meteorological reports, but did state that the collision occurred inside a cloud.[19] This was substantiated by the affidavit of Capt. Place, who was the commander of a Lockheed C-141B Starlifter, which was flying into New Delhi at the time of the crash.[15] 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, departures and arrivals both shared a single corridor within the civilian airspace around New Delhi. Most areas have separate corridors: one for departures and another one for arrivals. But the airspace of Delhi in 1996 had only one civilian corridor because much of the airspace was taken by the Indian Air Force.[15] Due to the crash, the air-crash investigation report recommended changes to air-traffic procedures and infrastructure in New Delhi's air-space:[10]

• 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 Directorate General of Civil Aviation subsequently made it mandatory for all aircraft flying in and out of India to be equipped with an airborne collision avoidance system. This set a worldwide precedent for mandatory use of Traffic Collision Avoidance System.[23]

As of 2021, there is an ongoing effort by the Charkhi Dadri district administration to develop a memorial honoring the victims of the mid-air collision. The proposed memorial, which would consist of names and other information of the victims, would be located at a to-be built memorial-park in the district. However, the district administration is waiting to get an approval for the project from the Haryana government, and plans to include the participation of Ministry of Civil Aviation of India, Airport Authority of India, and embassies of Saudi Arabia and Kazakhstan in the development of the memorial.[24]

Miditech, a company based in Gurugram, Haryana, produced a documentary about the disaster called Head On!, which aired on the National Geographic Channel.[15]

The disaster was also the subject of an episode in the documentary series Mayday (Air Crash Investigation) on 11 November 2009 entitled "Sight Unseen", also shown on the National Geographic Channel.[25]

• List of accidents and incidents involving airliners by airline

• Anas al-Qawz. A Pilot's Encounters. Obeikan, 2000. (in Arabic): Book by a Saudi pilot which discusses this incident
• Bhavya Dore. "Collision". Fifty Two. 9 October 2020.

External image
Pre-Crash photos of the two airliners at Airliners.net

• Directorate General of Civil Aviation
  • Final Report
  • OPERATIONS CIRCULAR NO.3 OF 1999 (Archived 24 February 2012 at the Wayback Machine)
• "Officials say hundreds feared killed in airline collision over India" (Archive). CNN. 12 November 1996.
• "Pilot error focus of India collision investigation" (Archive). CNN. 14 November 1996.
• Burns, John F. "Indian and Kazak Officials Trade Accusations in Air Collision." The New York Times. 15 November 1996.
• Centre for Disaster Management (Haryana Institute of Public Administration) Case Study: Charkhi Dadri Mid Air Collision
• New article on the crash
• Victims, crash site of the mid-air collision from Associated Press Archive