[Benjamin]

A C-130 Hercules has been circling the site where a beacon was activated after a plane with three crew went missing in Antarctica.

Searchers are hoping improving weather conditions will give them a chance to try to find the Twin Otter which disappeared on Wednesday night.

The Rescue Coordination Centre New Zealand (RCCNZ) said the Hercules was trying to spot the missing plane, after low cloud thwarted other attempts to find it.

The Hercules was carrying supplies for a search forward base being set up at the Beardmore Glacier, 50km from where the locator transmitter was activated about 3900 metres up at the northern end of the Queen Alexandra Range.

A Twin Otter plane had already landed at Beardmore today, and two helicopters were expected to arrive at the site around 4pm. A DC3 carrying supplies was also on its way.

The missing crew was understood to have survival equipment and enough food for five days.

The place where the beacon activated is within New Zealand’s search and rescue region, halfway between the South Pole and McMurdo Station - about 680km in each direction.

The three missing men are Canadians, including pilot Bob Heath who has been in the Arctic and Antarctic since 1991 with Calgary-based Kenn Borek Air, which owns the missing plane.

Antarctica New Zealand operations and infrastructure manager Graeme Ayres said winds in the area where the plane went missing had been blowing up to about 90 knots, "the visibility is about 200 metres on the ground. The temperatures with that will be about minus 30 degrees Celsius [plus] wind chill. They're hard conditions to work in and hard conditions to mount a rescue in."

A former executive with Kenn Borek Air said a computer track of the plane's flight showed it coming to a sudden stop at just under 4000m.

Former general manager Steve Penikett said a computer program monitoring the plane tracked a dip, climb and a sudden stop, Canadian newspaper The Globe and Mail reported.

Penikett watched on his computer as the plane was detected flying at just under 4000m, dropped to 2700m, then climbed back to its former height, travelling at 140 knots (260kmh), before suddenly recording "zero air speed".

"It's my candid opinion that this aircraft flew into the rocks," he said

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