Incident Overview
On a regular scheduled service, a Kazair Ilyushin Il-76TD operating as flight KZA1907 departed Shymkent Airport bound for New Delhi-Indira Gandhi. The aircraft carried 27 passengers and 10 crew members. The flight was uneventful until the crew received clearance to begin descent to New Delhi via route G452 and were instructed to maintain flight level 150 (FL150; 15,000 feet).
At 1833 local time, a Boeing 747-168B operated by Saudi Arabian Airlines (Saudia) as flight SV763 departed New Delhi-Indira Gandhi Airport for Jeddah with an intermediate stop in Dhahran. This aircraft carried 289 passengers and 23 crew members. After takeoff, its crew was instructed to climb to flight level 140 (FL140; 14,000 feet) via the same route G452.
Collision and Crash
For reasons that remain unknown, the Kazair crew continued their descent below FL150 without clearance. At 1840 local time, seven minutes after the Saudia B747 departed, the two aircraft faced each other and collided at FL140. After the collision, both aircraft entered an uncontrolled descent and crashed in an open field approximately 3 kilometers from Charkhi Dadri, about 80 kilometers west of New Delhi-Indira Gandhi Airport.
Both aircraft were destroyed by impact forces and a post-crash fire. All 349 occupants on both aircraft were killed.
Probable Cause
The official investigation determined that the collision was the consequence of the failure of the Kazair crew to follow the assigned altitude of 15,000 feet while approaching New Delhi. The Kazair Il-76 crew was instructed by air traffic control to continue descent to Indira Gandhi Airport via route G452 but at an altitude of 15,000 feet (the Saudia B747 was cleared to 14,000 feet). For unknown reasons, the Kazair crew continued descent below FL150 without clearance until both aircraft faced each other and collided. During the minutes preceding the accident, both the Kazair and Saudia crews had been informed by air traffic control about other traffic.