A three-nation mission to fly a patient from the US McMurdo station is under way in the depths of an Antarctic winter.
An Australian aircraft has landed at McMurdo's Pegasus ice runway to pick up the ailing US expeditioner after a five-hour flight from Christchurch in New Zealand, the Environment Department's Antarctic Division said.
The flight was timed to arrive in midday twilight on the specially groomed runway, one of few in the Antarctic that can take a wheeled landing by the Australian Airbus A319.
Despite the polar darkness and hostile conditions, the US is able to clear access at its McMurdo base for much of the year.
The aircraft was monitored on the way to Antarctica by the Royal New Zealand Air Force, which provided search and rescue coverage, under an asset-sharing program between the three nations.
The US National Science Foundation said the patient, whose identity it would not release, was suffering from a condition that might require treatment beyond that available at McMurdo's medical facility.
"The patient is currently stable but may require immediate corrective surgery," an NSF statement said.
Antarctic Division spokeswoman Patti Lucas said it was yet to be advised when the aircraft would leave McMurdo.