On the morning of 28 November 1979, Flight 901 left Māngere airport, Auckland, for an 11-hour return sightseeing flight to Antarctica. At 12.49 p.m. the aircraft crashed into the lower slopes of Mount Erebus killing all 237 passengers and 20 crew on board.
Despite Flight 901 crashing in one of the most isolated parts of the world, evidence from the crash site was extensive. Both the cockpit voice recorder and the flight data recorder were in working order and able to be deciphered. Extensive photographic footage from the moments before the crash was available
The New Zealand Government announced a further one-man Royal Commission of Inquiry into the accident, to be performed by judge Justice Peter Mahon.
Mahon’s report, released on 27 April 1981, cleared the crew of blame for the disaster. Mahon said the single, dominant and effective cause of the crash was Air New Zealand’s alteration of the flight plan waypoint coordinates in the ground navigation computer without advising the crew. The new flight plan took the aircraft directly over the mountain, rather than along its flank.
The accident is New Zealand’s deadliest peacetime disaster, as well as the deadliest accident in the history of Air New Zealand.