One will stay at the British station Rothera for search and rescue purposes, while the other will travel on to the Amundsen-Scott Research station at the South Pole.
The planes left Calgary on June 15 and aren’t expected to arrive at their destination until June 19.
The National Science Foundation says a seasonal employee with Lockheed Martin at the Amundsen-Scott station requires hospitalization and must be evacuated.
No further personal or medical information is being released in order to preserve the patient’s privacy.
Foundation spokesman Peter West says they don’t normally schedule flights for this time of year because of darkness and the extreme cold, which hovers at around -60 C during the winter months.
He says they’re monitoring the situation closely to see when the weather will co-operate.
“Their equipment, their aircraft, are better suited for the cooler weather than some other options,” says West. “We’re keeping a careful eye on the weather, I don’t know what the window is that far out.”
It is the third time in 15 years that Kenn Borek Air has carried out similar flights, with the other evacuations occurring in 2001 and 2003.
The company made improvements to its navigation charts for the Antarctic after three Canadians were killed when a Kenn Borek plane crashed into an Antarctic mountainside in January 2013.
The bodies of Bob Heath, 55, of Inuvik, N.W.T., Perry Andersen, 36, of Collingwood, Ont., and Mike Denton, 25, of Calgary remain on Mount Elizabeth, entombed in the wreckage of the plane in which they died.
Transportation Safety Board investigators were unable to pinpoint the cause of the crash.