( CNN ) -- Slowed , but not daunted , by Antarctic winds topping 100 mph , low visibility and snow , rescuers Saturday pounced on improving weather conditions to move closer to where a plane carrying three Canadians sent out emergency beacon signals . The condition of the three crew members on the Twin Otter operated by Calgary-based Kenn Borek Air Ltd. was not known nearly three days after the flight went missing and rescue attempts began . The plane was flying from the South Pole to an Italian base at Terra Nova Bay , Maritime New Zealand said . `` It is difficult to think of a more difficult environment , '' said Steve Rendle , spokesman for Rescue Coordination Centre New Zealand . The beacon stopped working Thursday evening , possibly because the battery had run out , about a day after the plane was reported missing . By then , rescuers had pinpointed the location , but harsh weather has made visual sightings impossible , Rendle said . Winds , for example , reached nearly 105 mph Wednesday . One search aircraft reached a camp about 30 miles from where the beacon sounded . Two helicopters were moving toward the forward base on a glacier Saturday afternoon . A C-130 Hercules aircraft circled the beacon activation site , attempting to make visual contact . `` We 've got a reasonably positive forecast for that site , '' Rendle said from Wellington . The missing crew 's survival kit includes survival suits , mountain tents and enough food and water for five days . The aircraft is believed to be at a height of 13,000 feet near the top of Mount Elizabeth , part of the rugged Queen Alexandra Range . It is a long distance from any bases in Antarctica . `` We would expect them to be with the plane , '' Rendle said of the crew . `` Common sense would dictate you stay with the beacon . '' Kenn Borek Air Ltd. did not immediately return a message left by CNN on Friday night . In a statement Wednesday , the airline described the flight as overdue . It did not release names of the crew members . According to its website , the airline has one of the largest Twin Otter fleets in the world . `` We are best known for our remote polar services utilizing ski-equipped Twin Otter , '' it said . `` KBAL provides a wide range of additional services including medevac , survey , paradrop , float operations , third-party maintenance and overhaul . '' The Queen Alexandra Range , about 100 miles long , was named by Ernest Shackleton during the British Antarctic expedition in 1907-1909 . Peter West , spokesman for the National Science Foundation , which oversees the U.S. Antarctic Program , said 24 hours of daylight this time of year should help rescue efforts . CNN 's Dave Alsup and Erica Harrington contributed to this report .
Rescue aircraft move closer to airplane beacon . one British were flying from the South Pole to Antarctica in the South Pole . The plane did not arrive , and the emergency locator activated , Rendle officials said . Calling terrain inhospitable an understatement .