Bell 407 crash near 120 miles N of Patriot Hills, Ronne Ice Shelf, Antarctica

The helicopter was attempting a pole-to-pole circumnavigation, having left New York in October and reached the South Pole on 17 December. Flying north from Patriot Hills toward Fossil Bluff via a fuel cache, the crew had a favourable met briefing and departed under clear skies, cruising at 1,000 feet. About 100 miles short of the cache the cloud increased, though the base remained high with good visibility. Without warning the helicopter entered white-out and the crew lost all visual reference. Reversing course failed to clear it, so the commander began a descent with the other pilot calling radio altitude. Passing 200 feet they still could not see the surface; at about 45 knots, just as a radio altitude of 140 feet was called, the helicopter struck the surface abruptly. The engine stopped and it came to rest upright with severe damage to the tail boom, rotor blades and fuselage. The commander suffered back injuries consistent with a high vertical impact and the other pilot a dislocated elbow. They sheltered from the -30°C conditions and activated a beacon and satellite phone; a Twin Otter reached them about four hours later. The commander noted afterwards that pilots experienced in Antarctic flying are aware of a tendency for radio altimeters to misread over dry snow.