N897TH

On July 20, 2002, at 1830 central daylight time, a Schweizer 269C-1, N897TH, owned and piloted by a private pilot, was substantially damaged during an aborted takeoff from a private grass airstrip near Askov, Minnesota. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 personal flight was not operating on a flight plan. The pilot was uninjured. The local flight was originating at the time of the accident.

The pilot stated that the helicopter immediately went into a right hand spin upon lift off while 5-10 feet above the ground. He could not get the spin to completely stop. The helicopter fell on its side because he had too much sideward motion when he attempted to land.

The pilot held a private pilot certificate with a single engine land rating with a reported total flight time of 640 hours in single engine airplanes. He had a helicopter solo endorsement and reported a total flight time of 41 hours in rotorcraft, of which 5 hours were in the last 30 days.

Examination of the helicopter by the Federal Aviation Administration revealed the main rotor exhibited impact damage and tail rotor drive shaft exhibited torsional buckling. Lines formed by these buckles sloped upwards towards the tail rotor. The tail to nose rotation of the tail rotor drive shaft is in the clockwise direction on Schweizer 269C helicopters. Flight control continuity from cockpit controls to the control surfaces was confirmed. The tail rotor blades did not exhibit chordwise damage, bending or crushing. The tail rotor was removed and shipped to the National Transportation Board for examination. The tail rotor fracture surfaces and attaching hardware were consistent with overstress.