(Editor's note: This story includes a correction.)

An aircraft carrying three men went missing in Antarctica on Wednesday and the plane’s emergency locator beacon was activated, according to the National Science Foundation.  

The status of those aboard remains unknown, NSF spokesman Peter West said. The Toronto Star reported that the three men are Canadian.

West said those aboard were likely a pilot, co-pilot and a flight engineer carrying or picking up cargo. They had been contracted to support a branch of the Italian Antarctic Program that focuses on new technology and energy – specifically nuclear fusion and fission.

The aircraft, a de Havilland Twin Otter, was returning from the South Pole to Terra Nova Bay, where the Italian Antarctic Program is based, when contact was lost as the plane flew over a remote area of the Transantarctic Mountains.

The plane was contracted out by Kenn Borek Air Ltd., a Canadian company based in Calgary that charters aircraft to the U.S. Antarctic program.

Rescue crews, based at the New Zealand Rescue Coordination Center, know generally where the beacon is coming from, but cloudy and windy conditions have prevented rescue planes from attempting a landing near the downed plane.

“There are not as many weather stations, so it’s difficult to find out what the weather is,” West said. “There was low cloud, limited visibility in the air in the area where they were looking for the aircraft -- some blowing snow and issues with cloud.”

www.nsf.gov

A Twin Otter aircraft, photographed here in 2006, at the National Science Foundation's Amundsen-Scott South Pole Station.

West said he didn’t know whether the flight crew carried cold weather survival gear. At the U.S. station, protocol demands that anyone leaving the base must have protective gear – typically a parka, wind pants, insulated boots, a tent, food and a stove to melt snow into water.

He said that he doesn't recall a similar crash in his 14 years as a spokesman for the Antarctic program.

Antarctica, the size of U.S. and Mexico combined, is vast, white and isolated. There are about 50 research stations, some of them year-round, others open during research season, which runs roughly between October and early February – summer in the Southern Hemisphere. During those months, the largest is McMurdo Station, the U.S. Antarctic station on Ross Island, with about 1,100 people.

“It’s a harsh continent,” West said. “People take extra care if they can.”