Multiple aircraft have now flown over an Antarctic mountain range where three Canadians went down in a small plane, but poor weather has prevented visual contact, and aviation experts familiar with the aircraft's course fear the worst.
The Canadian men – two pilots and a mechanic – were aboard a twin-engine propeller plane that went down in a "very remote" spot about 680 kilometres from the south pole. Its emergency beacon activated late on Wednesday Antarctic time, signalling a problem as well as its exact location, but there has been no radio or satellite phone contact with the men in the two days that followed. Heavy cloud cover and strong winds have stymied search and rescue efforts, but authorities in New Zealand, which is leading the mission, say the forecast looks promising over the next 24 hours.
"We are still operating with the expectation we will find them alive," said Rescue Coordination Centre New Zealand co-ordinator Kevin Banaghan
The ski-equipped Twin Otter and its crew belong to Kenn Borek Air Ltd., a Calgary-based airline with extensive experience flying in the most inhospitable places on Earth. The plane was on a routine flight from the south pole to an Italian research station at Terra Nova Bay, which would take it over the Queen Alexandra mountain range.
The plane is equipped with survival gear, including tents, as well as food and water to last five days. But current and former Kenn Borek employees have faint hope for a successful rescue. They believe that, based on the plane's last known flight path, the pilot was fighting extreme winds and likely crashed into a mountain.
A computer program monitoring the aircraft tracked a dip, climb and sudden stop, said Steve Penikett, the company's former general manager.
Mr. Penikett said a former dispatcher for the company who is now based in Kabul watched his computer helplessly as a satellite detected the aircraft flying at 13,000 feet, before dropping to 8,800 feet and then climbing back up to 13,000 feet at 140 knots before suddenly recording "zero air speed." All of this happened "within minutes," he added.
"It's my candid opinion that this aircraft flew into the rocks," Mr. Penikett said. "Anything's possible and again I hope for the best. But I've been through quite a few of these and it doesn't look very good to me."
Bob Heath, who has been a pilot with the airline in the Arctic and Antarctic since 1991, has been identified as among the missing crew members. His wife, Lucy, was waiting for news at their home in Inuvik, NWT. Ms. Heath referred calls to Kenn Borek Air. "We are asking for privacy at this time," company spokeswoman Marlene Egeland said.
Mr. Penikett suspects the pilot may have hit "subsiding air." That's a mountain wave effect when extreme down forces push on the aircraft. A Twin Otter doesn't have the power of a commercial jetliner to maintain altitude.
He also said he spoke with a Kenn Borek pilot who remarked that the missing plane's flight path is also cause for concern.
"You can't do that trip below 15,000 feet… to be safe," the pilot told him.
The aircraft's beacon was on the ground after the crash, transmitting from 13,000 feet, before its battery died in extremely cold conditions, according to New Zealand rescue officials.
Given Mr. Heath's wealth of experience, Mr. Penikett said it's possible the men, who are equipped with survival gear including tents, are waiting for rescue.
"It may be that he's sitting on a plateau somewhere, but … I doubt it," he said. "All the indicators are not good."
By Friday morning local time, New Zealand Rescue Co-ordination Centre spokesman Michael Flyger said the weather had improved dramatically, with 90-knot winds (170 kilometre per hour) dropping to around 20 knots (35 km/h) and the heavy clouds were expected to break up, which allowed another of the company's Twin Otters to take off. Later, mission co-ordinator Mr. Banaghan said wind and cloud prevented visual contact. (Two previous flyovers produced no actual sightings of the downed plane and the conditions are too grim to allow the helicopters on standby to fly.) Weather would remain the main challenge for another 12 hours, he added, but over the next 24 hours the forecast showed improvement.
In a statement released late Thursday Calgary time, Kenn Borek Air said one of its planes attempted to land at a base camp 30 nautical miles from the crash site, but bad weather turned it back to a base camp position 200 nautical miles away. A second of the company's planes is acting as a "spotter" circling in a high-level flight pattern over the location.
(Antarctica is on New Zealand time, which is 20 hours ahead of Kenn Borek's home base in Calgary.)
Officials plan to set up a forward base about 50 kilometres from the site and wait for weather to improve more. The next step would be to drop supplies; if conditions are good enough, a helicopter might be dispatched.
The missing plane, which is in New Zealand's search-and-rescue region, is halfway between the south pole and Scott Base, which is New Zealand's permanent outpost in Antarctica.
Temperatures at Scott Base, as well as nearby McMurdo Station, where rescuers were waiting, hovered around -7 C during the day. Conditions would be much colder and more windy in the mountains.
The company said in a statement that the aircraft was "repositioning" between bases when it became "categorized as an overdue aircraft."
According to the Italian National Agency for New Technologies, Energy and Sustainable Economic Development, which handles logistics for that country's Antarctic research program, the plane was carrying two pilots and a mechanic bound for its Mario Zucchelli base to support scientists there.
Kenn Borek is a long-standing polar airline whose services include medevac, survey and paradrop operations. In April 2001, they made history in the daring rescue of an ailing U.S. doctor by making the first landing at the pole in the Antarctic winter.
The company was established in Canada's north in 1970 and, according to their website, started operating in the Antarctic in 1984. The company boasts it has one of the largest Twin Otter fleets in the world and says it sent 14 aircraft south for the 2012 Antarctic season.
On his LinkedIn profile, Mr. Heath says he has flown for them since the early 1990s. It indicates that he helps train pilots and does about 50 "checkrides" – in which he monitors trainees in the air to assess their ability – each year.
In an interview two years ago published by the Australian Antarctic Division, he praised the beauty of the polar regions and the people he meets there.
"One day a month on average actually feels like a work day. We do some long hours but you do not notice the time going by. We have good times, see spectacular things and meet great people," he said.
"It is that small community spirit where people give so much of themselves, be productive and cheerful. It really cures you of having to do everything by yourself, as everyone pitches in."
David Connelly, who first flew with Mr. Heath in 1992 and extensively through Alaska and the territories until about 2005, described him as skilled in inclement conditions as well as short landings and take-offs. He remembered being aboard Mr. Heath's plane in Anchorage 20 years ago when horrible winter conditions sent a 747 ahead of them off the runway. Mr. Heath "piloted us out of there with no problem" and he later announced his 10,000th hour in the air as they flew over Mount McKinley.
He said Mr. Heath has landed and taken off in snow and ice with just 200 metres of strip. He remains confident in a successful rescue.
"If anyone can make it through, Bob can," he said.