A pilot and two researchers injured in an Antarctic helicopter crash that left their aircraft "in pieces" have been rescued in a complex recovery mission, Australian officials said Tuesday.
The trio spent almost 24 hours in sub-zero temperatures awaiting rescue after their Squirrel helicopter came down 150 nautical miles from Australia's Davis research station in Antarctica.
The chopper was returning from a penguin colony survey near the Amery ice shelf when it crashed on Sunday night, breaking up on impact and seriously injuring the pilot and passengers.
"It's in a few pieces," said Australian Antarctic Division director Tony Fleming.
A second helicopter flying in tandem immediately set down to assist the injured and spent Monday keeping them sheltered and warm until a medical support and rescue operation could be mounted, with bad weather hampering efforts.
Rescuers had a narrow window of favorable conditions late Monday to retrieve the group in a complex ferrying operation involving three aircraft.
A fixed-wing Basler scouted for a staging post on Sansom Island, 90 kilometers (55 miles) from the crash site, where a Twin Otter could land to collect both chopper crews.
The second helicopter ferried the group, in turns, to Sansom, and they were then transferred to Davis Station, some 220 kilometers distant.
The Basler provided guidance and support for the mission, which was completed at 11.30pm on Monday night Australian time (12.30 GMT).
"All three (injured) people are in a stable condition," the Australian Antarctic Division said.
"A comprehensive medical assessment is being undertaken by the Davis station doctor and lay medical team, with support from the Australian Antarctic Division?s Polar Medicine Unit at Kingston in Tasmania."
The nature of their injuries is not known, but at least one is reported to have spinal damage. All were conscious and had stable vital signs on their return to Davis.
A decision is yet to be made on whether they require evacuation to Australia.
Environment Minister Greg Hunt commended the Antarctic Division -- an Australian government body -- on their "speedy and successful" response to the crash.
"Their quick thinking and precise planning ensured that all the injured were cared for and kept safe during the ordeal," he said.
"The accident is a reminder of the challenges facing scientists working in this environment."
The cause of the crash remains unclear and will be investigated by the Australian Transport Safety Bureau.
Davis is the southernmost of Australia's three Antarctic stations, which also include Casey and Mawson, along with a sub-Antarctic station at Macquarie Island.