A break in the weather has allowed a Twin Otter rescue aircraft to land about 50 kilometres from where a plane carrying three Canadian crew members is believed to have gone down in the Antarctic.

The search plane touched down at Beardmore Glacier on Saturday (local time) but the crew reported that because of low cloud cover, they did not spot the missing aircraft owned by Calgary-based Kenn Borek Air. The plane disappeared Wednesday on a flight over the Queen Alexandra mountain range, said New Zealand's Rescue Co-ordination Centre.

The rescuers are setting up a base camp to use as a launch pad to get into the area of the missing men's last known position. Two helicopters are en route to the base camp along with a DC-3 plane carrying supplies. A C-130 Hercules aircraft was circling the site where the missing plane's beacon activated hoping to spot the plane or the men. It was to land later with its supplies at Beardmore Glacier.

The missing Twin Otter's emergency locator transmitter was activated around 10 p.m. local time Wednesday as the plane travelled from a U.S. research station at the South Pole to an Italian research base in Terra Nova Bay.

The signal came from the north end of Antarctica's Queen Alexandra range -- about halfway between the South Pole and McMurdo Station. While searchers have flown over the area since the plane vanished, their hunt has been hampered by heavy cloud cover and at time hurricane-force winds, said officials.

The beacon stopped transmitting likely because the battery -- good for approximately 24 hours-- died and there has been no contact with the crew. But their plane was equipped with survival suits, cold-weather tents and food and water to last up to five days.

Experienced pilot missing

Friends have identified the pilot as Bob Heath from the Northwest Territories, an experienced pilot in both the Antarctic and Arctic. Heath has more than 20 yearsā€™ experience flying in extreme conditions.

His wife, Lucy Heath, told the Calgary Sun newspaper that she'd been called by airline officials and told "Bob's plane was down, and they were trying to reach it."

She said she was just waiting for more news: "I'm so worried."

Heath, who lives in Inuvik, N.W.T., has logged thousands of hours teaching young flyers in regions from the Maritimes to northern Ontario and administers tests to other pilots, said Roger Townsend, who was a co-pilot with Heath out of Red Lake, Ont. Flying with Heath was always a learning experience, Townsend said.

"He used it as an opportunity to impart knowledge. He's a true instructor with an extraordinary passion for teaching and training."

On the online networking site LinkedIn, Heath writes that he typically spends this time of year coaching and mentoring other pilots to upgrade their skills in polar regions.

Media reports have identified the copilot as 25-year-old Mike Denton, a newlywed from Calgary whose photographs of planes appear on the Kenn Borek Air website. The third crew member has not yet been identified.

Officials from the Canadian High Commission in Wellington are working closely with local authorities organizing the search from New Zealand.

"Consular officials stand ready to provide consular services as required," said spokesperson Barbara Harvey.