Boeing 747-237B – VT-EBD

Incident Overview

Date: Sunday 1 January 1978

Aircraft Type: Boeing 747-237B

Owner/operator: Air-India

Registration Number: VT-EBD

Location: 3 km W off Bombay-Santacruz Airport (BOM) – ÿ India

Phase of Flight: Initial climb

Status: Destroyed, written off

Casualties: Fatalities: 213 / Occupants: 213

Component Affected: Flight Instruments (ADI, Standby Horizon Indicator – SHI)Flight Instruments (ADI, Standby Horizon Indicator – SHI)

Category: Accident

On New Year’s Day, 1978, Air-India Flight AI855 crashed into the Arabian Sea after takeoff from Bombay-Santacruz Airport, India, resulting in the loss of all 213 passengers and crew. The aircraft, a Boeing 747-200 named ‘Emperor Ashoka’, was cleared to climb to 8000 feet and report leaving 2400 feet. After takeoff, the ADI malfunctioned, causing the aircraft to remain in a right-bank indication while the wings were level. The captain, initially unaware of the ADI’s error, continued to roll to the left, resulting in a 40-degree left bank. The flight engineer alerted the captain to a potential issue, prompting him to avoid the roll. The aircraft descended to approximately 2000 feet, then crashed into shallow water 3 km offshore at an angle of 35-40 degrees. The probable cause was attributed to irrational control wheel inputs by the captain, stemming from a malfunctioning ADI, and the crew’s failure to accurately assess the aircraft’s attitude.On New Year’s Day, 1978, Air-India Flight AI855 crashed into the Arabian Sea after takeoff from Bombay-Santacruz Airport, India, resulting in the loss of all 213 passengers and crew. The aircraft, a Boeing 747-200 named ‘Emperor Ashoka’, was cleared to climb to 8000 feet and report leaving 2400 feet. After takeoff, the ADI malfunctioned, causing the aircraft to remain in a right-bank indication while the wings were level. The captain, initially unaware of the ADI’s error, continued to roll to the left, resulting in a 40-degree left bank. The flight engineer alerted the captain to a potential issue, prompting him to avoid the roll. The aircraft descended to approximately 2000 feet, then crashed into shallow water 3 km offshore at an angle of 35-40 degrees. The probable cause was attributed to irrational control wheel inputs by the captain, stemming from a malfunctioning ADI, and the crew’s failure to accurately assess the aircraft’s attitude.

Description

Air-India flight 855, a Boeing 747-200, crashed into the sea following an ADI malfunction after takeoff from Bombay-Santacruz Airport, India, killing all 213 occupants. New year’s day 1978. It’s 20:12 when Air-India flight AI855 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.

Primary Cause

Malfunctioning Attitude Director Indicator (ADI) leading to incorrect aircraft attitude assessment and control wheel input.Malfunctioning Attitude Director Indicator (ADI) leading to incorrect aircraft attitude assessment and control wheel input.

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