After starting initially with 45 passengers in Sydney and taking on more passengers on the stops to Darwin and Singapore,[5] Flight 771 departed from Bangkok at 15:16 UTC with 94 people aboard as stated by the load sheet, although the official flight plan stated there was to be 98 people aboard.

[8] At 18:20 the flight switched to the Bombay approach frequency and requested to initiate descent when over the point of Aurangabad to an altitude of 20,000 feet (6,100 m).

[8] The flight initiated descent at 18:24:36 UTC, descending from 35,000 to 20,000 feet (10,700 to 6,100 m) approximately twenty minutes before it was due to land at Bombay with an ETA at 18:45.

[9] At 18:38:54 the DC-8 reached an altitude of 5,000 feet; the flight plan provided by Alitalia prescribed a 100-mile (160 km) descent to Bombay in 13 minutes.

Chart number 21 from the radio facility did not show the terrain the flight crashed into and only indicated the presence of a location 13 miles (11 nmi; 21 km) to the north at a height of 5,400 feet (1,600 m).

[11] Investigators concluded that errors in navigation led the pilot to think he was closer to the necessary point of descent than in reality, resulting in a premature descent for a straight-in instrument approach at night, resulting in controlled flight into terrain.

Failure on the part of the pilot to make use of the navigational facilities available in order to ascertain the correct position, of the aircraft.