Narrative:
New year's day 1978. It's 20:12 when Air-India flight 855 departs Bombay Airport's runway 27 for a flight to Dubai. The Boeing 747-200, named "Emperor Ashoka", was cleared to climb to 8000 feet and report leaving 2400 feet. Approx. one minute after takeoff the plane enters a gentle right turn heading for the Arabian Sea. The Attitude Director Indicator (ADI) however remained in a right-bank indication, while the wings were already level. The captain then said: "What's happened here, my instrument...". The co-pilot didn't note the captain's concern and replied: "Mine has also toppled, look's fine." The flight engineer however noticed the difference between the captain's ADI and the third spare ADI. Because it was dark outside and the aircraft was over the Arabian Sea, there was no visual contact with the horizon. The captain continued to roll to the left because, looking at his ADI, he still thinks the plane is in a right bank. As the airplane rolled through 40 degrees left, the flight engineer indicated to the captain: "Don't go by that one, don't go by that one...". The plane however continued to roll to the left, to 108 degrees left bank. The 747 started to descend from approx. 2000 feet altitude until it crashed into shallow (10 m deep) water, 3 km offshore in an approx. 35-40 degree nose down pitch.
PROBABLE CAUSE: The probable cause of this accident was due to the irrational control wheel inputs given by the captain following complete unawareness of the attitude of the aircraft on his part after Attitude Director Indicator (ADI) had malfunctioned. The crew failed to gain control based on the other flight instruments. He had failed to determine the attitude of the aircraft with the associated flight instruments including Standby Horizon Indicator. The co-pilot had failed to monitor the flight instruments and did not render any assistance to the captain in ascertaining the attitude of the aircraft.
Loss of situational awareness
Loss of control
» ICAO FILE NO. 78/1-0
» Jet-Airliner Unfälle seit 1952 / J. Richter, Chr. Wolf
accident date: 01-01-1978
type: Boeing 747-237B
registration: VT-EBD
| Status: | Accident investigation report completed and information captured |
| Date: | Sunday 1 January 1978 |
| Time: | 20:15 |
| Type: |  Boeing 747-237B |
| Operator: | Air-India |
| Registration: | VT-EBD |
| MSN: | 19959/124 |
| First flight: | 1971-03-08 (6 years 10 months) |
| Engines: | 4 Pratt & Whitney JT9D-7J |
| Crew: | Fatalities: 23 / Occupants: 23 |
| Passengers: | Fatalities: 190 / Occupants: 190 |
| Total: | Fatalities: 213 / Occupants: 213 |
| Aircraft damage: | Destroyed |
| Aircraft fate: | Written off (damaged beyond repair) |
| Location: | 3 km (1.9 mls) W off Bombay-Santacruz Airport (BOM) ( India)
|
| Phase: | En route (ENR) |
| Nature: | International Scheduled Passenger |
| Departure airport: | Bombay-Santacruz Airport (BOM/VABB), India |
| Dubai Airport (DXB/OMDB), United Arab Emirates | |
| Flightnumber: | AI855 |
New year's day 1978. It's 20:12 when Air-India flight 855 departs Bombay Airport's runway 27 for a flight to Dubai. The Boeing 747-200, named "Emperor Ashoka", was cleared to climb to 8000 feet and report leaving 2400 feet. Approx. one minute after takeoff the plane enters a gentle right turn heading for the Arabian Sea. The Attitude Director Indicator (ADI) however remained in a right-bank indication, while the wings were already level. The captain then said: "What's happened here, my instrument...". The co-pilot didn't note the captain's concern and replied: "Mine has also toppled, look's fine." The flight engineer however noticed the difference between the captain's ADI and the third spare ADI. Because it was dark outside and the aircraft was over the Arabian Sea, there was no visual contact with the horizon. The captain continued to roll to the left because, looking at his ADI, he still thinks the plane is in a right bank. As the airplane rolled through 40 degrees left, the flight engineer indicated to the captain: "Don't go by that one, don't go by that one...". The plane however continued to roll to the left, to 108 degrees left bank. The 747 started to descend from approx. 2000 feet altitude until it crashed into shallow (10 m deep) water, 3 km offshore in an approx. 35-40 degree nose down pitch.
Probable Cause:
PROBABLE CAUSE: The probable cause of this accident was due to the irrational control wheel inputs given by the captain following complete unawareness of the attitude of the aircraft on his part after Attitude Director Indicator (ADI) had malfunctioned. The crew failed to gain control based on the other flight instruments. He had failed to determine the attitude of the aircraft with the associated flight instruments including Standby Horizon Indicator. The co-pilot had failed to monitor the flight instruments and did not render any assistance to the captain in ascertaining the attitude of the aircraft.
Classification:
ADI issues Loss of situational awareness
Loss of control
Sources:
» Aviation Disasters / D. Gero» ICAO FILE NO. 78/1-0
» Jet-Airliner Unfälle seit 1952 / J. Richter, Chr. Wolf
Photos
accident date: 01-01-1978
type: Boeing 747-237B
registration: VT-EBD
Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Bombay-Santacruz Airport to Dubai Airport as the crow flies is 1915 km (1197 miles).
Accident location: Approximate; accuracy within a few kilometers.
Distance from Bombay-Santacruz Airport to Dubai Airport as the crow flies is 1915 km (1197 miles).
Accident location: Approximate; accuracy within a few kilometers.
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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Boeing 747
- 1574 built
- 8th loss
- 5th fatal accident
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India- The worst accident (at the time)
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