Denali Park, AK, USA
N197EH
Eurocopter France AS-350-B2
The pilot of the accident helicopter reported that he was attempting to takeoff from a glacier. During takeoff, he discovered the right landing gear skid was frozen to the surface of the glacier, and he decreased the collective control input. As he reduced the collective control input, the right skid broke free from the ice. He said that due to left cyclic input, when the right skid broke free from the ice, a left rolling moment was induced. The helicopter's main rotor blades subsequently contacted the surface of the glacier, and the helicopter rolled onto its right side.
On June 26, 2002, about 1115 Alaska daylight time, a Eurocopter AS-350-B2 helicopter, N197EH, sustained substantial damage following a loss of control during takeoff from a glacier, about 40 miles east of Denali National Park, Alaska. The helicopter was being operated by Era Aviation, Inc., as a visual flight rules (VFR) on-demand charter flight under Title 14, CFR Part 135, when the accident occurred. The commercial pilot and one passenger received minor injuries; the four other passengers were not injured. Visual meteorological conditions prevailed, and a company VFR flight plan was in effect. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC)on June 26, the pilot said he and the passengers had just completed a 20 minute glacier walk, and returned to the helicopter. He said they were going to depart the glacier as the third helicopter in a flight of three. He said as the first two helicopters passed by, he pulled up on the collective lever, and the left skid lifted up off the ice. He said as the left skid lifted off the ice , it exceeded the height where the right skid should have lifted off. He believed the right skid was frozen to the ice, so he started to reduce the collective input. The pilot said as he reduced the collective input, the right skid broke loose, and the helicopter rolled left. The main rotor blades struck the ice, and the helicopter flipped 180 degrees, coming to rest on its right side. In a subsequent written statement the operator's vice president of safety said, in part: "The right skid broke free causing the fuselage to "swing" laterally to the left. Due to the amount of cyclic input applied the fuselage moved left allowing the left skid to make contact with the ground providing a left lateral rolling moment. The main rotor blades made contact with the ground which caused the helicopter to pivot up and around the nose, and come to rest on its right side facing downhill." The transmission was torn loose from its mounts to the fuselage. The tail rotor and engine drive shafts were severed, and the three main rotor blades were destroyed.
The pilot's failure to maintain aircraft control during takeoff, which resulted in dynamic rollover of the helicopter. A contributing factor was the frozen terrain.
Source: NTSB Aviation Accident Database
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