1996 Charkhi Dadri mid-air collision
[6] The report also suggested technical enhancements (including ACAS and SSR) that would provide assistance in preventing a future crew's mistakes being allowed to go unchecked in real time.[7] Saudi Arabian Airlines Flight 763 was a Boeing 747-168B, registration HZ-AIH, departing from Delhi as part of a scheduled international Delhi–Dhahran–Jeddah passenger service with 312 people on board.[13] A company from Kyrgyzstan chartered the flight, and the passenger manifest mostly included ethnic Russian Kyrgyz citizens planning to go shopping in India."[9] Less than a minute later, at 18:40, the crew of a United States Air Force cargo flight made a radio call saying they had seen "a big explosion" at their two o'clock position.[citation needed] The crippled Saudi Boeing immediately lost control and went into a rapidly descending spiral with fire trailing from the wing, and broke up mid-air before crashing to the ground at a nearly supersonic speed of 1,135 km/h (613 kn; 705 mph).[15] The recorder of the Saudi Arabian plane revealed the pilots said the Islamic Istighfar (forgiveness prayer) and recited the Shahada before impact with the ground.The flight data recorders (FDR) were decoded by Kazakhstan Airlines and Saudia under the supervision of air crash investigators in Moscow and Farnborough, England, respectively.[9] 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.Instead, they concluded – from the Kazakhstani plane's misleading flight data records – that the aircraft had descended while their pilots were battling turbulence inside a bank of cumulus clouds.[17] Due to the crash, the air-crash investigation report recommended changes to air-traffic procedures and infrastructure in New Delhi's air-space:[9] 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.