The cause of the crash of Air New Zealand Flight 901 ("the Mount
Erebus disaster") is not fully agreed on. The most widely accepted
cause is this:
When Air New Zealand flights to Antarctica started in 1977, a
flight path was set up for the DC-10 aircraft. The original plan
had the path going over Mount Erebus from Cape Hallett to McMurdo
Station, but this was just a guideline - pilots still had control
over the plane and flew it to the west down McMurdo Sound.
In 1978 when Air New Zealand fed all its coordinates into a new
ground computer, a typing error was made in the location of McMurdo
Station, resulting in the route moving west and making the plane go
down McMurdo Sound by default.
Air New Zealand realised its mistake in mid-November 1979, and
early on the morning of 28 November 1979 (the day of the crash)
fixed the route to go to McMurdo Station over Mount Erebus.
However, the pilots of Flight 901 were trained on the old route
down McMurdo Sound and were not told of the changes. The pilots
thought they were going down McMurdo Sound - the DC-10's corrected
coordinates took them straight towards Mount Erebus.
Of course it would of been obvious they were heading towards a
mountain - but due to unique Antarctic conditions, a sector
whiteout occurred which blended the mountain into the sky, making
it indistinguishable to the untrained eye. Both the pilots and
McMurdo station thought the plane was going down McMurdo Sound and
McMurdo allowed the plane down to 1500ft to allow the passengers a
better view. Mount Erebus was just under 13,000ft high - so
naturally the plane was going to crash into it.
At 12:49pm local time, the Ground Proximity Warning System
sounded that they were getting to close to terrain. Captain Jim
Collins, not knowing that he was heading towards the mountain,
immediately requested go-around power to climb up, but it was too
late. Six seconds after the GPWS sounded, the DC-10 crashed into
the slopes of Mount Erebus, instantly killing all 257 people on
board.
You can read more, below.