On 9 November 1979, Captain Jim Collins and First Officer Greg Cassin, members of the flight crew rostered on Air New Zealand's 28 November Antarctic flight, attended a route qualification briefing. This covered the instrument flight rules (IFR) route to the McMurdo area, which stipulated a minimum instrument meteorological conditions (IMC) altitude en route of 16,000 ft (4877 m).
They were also advised of a visual meteorological conditions (VMC) let-down procedure which permitted them to descend to 6000 ft (1829 m) over McMurdo if visibility was good. Material presented at the briefing, including printouts of a flight plan used for a previous trip, gave the impression that the IFR route would take them down McMurdo Sound over flat sea ice.
In the early hours of 28 November, a navigational coordinate in the flight plan presented at the briefing was changed. The airline’s navigation section believed it was making a minor adjustment to the flight’s long-standing destination point, but a typing error 14 months earlier meant it had actually shifted this point 27 nautical miles to the east. Instead of the IFR route taking Flight TE901 over sea ice, as Collins and Cassin had been briefed, it would take them directly over Mt Erebus, a 3794-metre active volcano. The flight crew were not alerted to the change. On the morning of 28 November they received the adjusted flight plan and entered these coordinates into the onboard computer.
Shortly before 8.30 a.m. NZDT* on 28 November 1979, Air New Zealand Flight TE901 left Māngere airport, Auckland, for its 11-hour return flight to Antarctica. The McDonnell-Douglas DC-10 was scheduled to arrive over Antarctica between 12 and 1 p.m. NZST, and from around noon it had ongoing contact with both 'Mac Centre', the United States Navy's air traffic control centre at McMurdo Station, and the 'Ice Tower' at nearby Williams Field. At 12.45 p.m. NZST Cassin advised Mac Centre that the aircraft was at 6000 ft (1829 m) in the course of descending to 2000 ft (610 m) in VMC. This was the final communication from TE901. Four minutes and 42 seconds later, at 12.49 p.m. NZST, the aircraft crashed into the lower slopes of Mt Erebus, killing all on board.
*On the day of the Erebus disaster there was a one-hour time difference between New Zealand and McMurdo Station. McMurdo Station was operating under New Zealand Standard Time (NZST) while New Zealand was operating under daylight saving or New Zealand Daylight Time (NZDT). Scott Base and McMurdo Station did not begin observing daylight saving until the summer of 1992/93.
