Investigation Summary
The investigation into Flight 771 highlighted significant human factors and procedural lapses. The captain, while highly experienced with over 13,000 hours, was relatively new to the DC-8 and the specific Bangkok to Bombay route. The flight was part of a grueling multi-leg journey originating in Sydney, with scheduled stops in Darwin, Bangkok, Bombay, Karachi, and Tehran before its final destination in Rome. The captain had only completed one familiarization flight on the Bangkok-Bombay leg, and during that flight, he did not perform the actual landing. On the night of the accident, the crew failed to utilize the full suite of available navigational aids, such as the Doppler radar or ADF, to verify their exact position before descending. Instead, they relied on dead reckoning or a misinterpretation of their distance from the Santacruz Airport. The descent was cleared by Bombay Approach to 4,000 feet, but the aircraft was still roughly 84 kilometers away from the airport, placing it directly in the path of the Western Ghats mountains.
Final Conclusions
The probable cause was a navigation error that led the pilot to believe he was nearer his destination than he actually was, causing a premature descent in instrument conditions at night. Contributing factors included the pilot's failure to use available navigational facilities to ascertain the aircraft's correct position, the infringement of prescribed minimum safe altitudes, and the pilot's lack of familiarity with the terrain on the route.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
Had been a pilot since 1939; 50 years old at the time of the accident.
Systems & Failure Modes
Doppler Radar
A self-contained navigation system on the aircraft that could have provided ground speed and drift information to help determine position.
ADF Receiver
Automatic Direction Finder used to navigate via non-directional beacons (NDBs); the crew failed to use this to verify their distance from the airport.
Interesting Facts
- 01The aircraft was a nearly new Douglas DC-8-43 with only 964 flight hours.
- 02The crash site was located approximately 84 kilometers (52 miles) north-east of Bombay.
- 03The aircraft was not equipped with flight data or cockpit voice recorders, as they were not required at the time.
- 04The captain had 13,700 total flight hours but only 1,396 hours on the DC-8 type.
- 05The accident occurred at night (00:10 local time) under instrument meteorological conditions.
Safety Actions & Advisories
Route Familiarization Requirements
The investigation highlighted the inadequacy of the captain's route familiarization, leading to stricter oversight of pilot training for specific international routes involving challenging terrain.