Air India Flight 855

Air India Flight 855 was a scheduled passenger flight from Bombay (now Mumbai), India, to Dubai, United Arab Emirates. On 1 January 1978, the Boeing 747 operating the flight crashed into the Arabian Sea about 3 km off the coast of Bandra, less than two minutes after take-off, killing all 213 passengers and crew on board. An investigation into the crash determined the most likely probable cause was the captain becoming spatially disoriented and losing control of the aircraft after the failure of one of the flight instruments. It was Air India's deadliest air disaster until it was surpassed nearly 7 and a half years later by the bombing of Flight 182 and was the deadliest airliner accident in Indian history until it was surpassed nearly 19 years later by the Charkhi Dadri mid-air collision.

Accident

The aircraft departed from Bombay's Santa Cruz Airport (later Sahar Airport, now called Chhatrapati Shivaji Maharaj International Airport). The destination was Dubai International Airport in Dubai.

Approximately one minute after takeoff from runway 27, Captain Kukar made a scheduled right turn upon crossing the Bombay coastline over the Arabian Sea, after which the aircraft briefly returned to a normal level position. Soon it began rolling to the left, and never regained level flight.

The cockpit voice recorder recovered from the wreckage revealed that Captain Kukar was the first to notice a problem, when he said, "What's happened here, my instruments..." The captain was explaining that his attitude direction indicator (ADI) had "toppled", meaning that it was still showing the aircraft in a right bank. First Officer Virmani, whose presumably functional ADI was now showing a left bank (and not noticing the captain's concern), said, "Mine has also toppled, looks fine." It is believed that the Captain mistakenly took this to mean that both primary ADIs were indicating a right bank, in effect confirming what he believed he was seeing. It was after sunset and the aircraft was flying over a dark Arabian Sea, leaving the aircrew unable to visually cross-check their ADI instrument readings with the actual horizon outside the cockpit windows.

The Boeing 747 had a third backup ADI in the centre instrument panel between the two pilots, and the transcripts of the cockpit conversation showed Flight Engineer Faria telling the captain, "Don't go by that one, don't go by that one..." trying to direct his attention towards that third ADI, or perhaps to another instrument called the turn and bank indicator, just five seconds before the aircraft impacted the sea.

The captain's mistaken perception of the aircraft's attitude resulted in him using the aircraft flight control system to add more left bank and left rudder, causing the Boeing 747 to roll further left into a bank of 108 degrees and rapidly lose altitude. Just 101 seconds after leaving the runway, the jet hit the Arabian Sea at an estimated 35-degree nose-down angle. There were no survivors among the 190 passengers and 23 crew members.