ANC98LA032

The pilot was practicing slope landings in preparation for an upcoming check ride. According to the pilot, he was positioning the helicopter close to the hill in order to start the maneuver. The next thing the pilot recalls, the helicopter had rolled to its left, and was upside down and on top of the hill that he was attempting to land beside. The day following the accident, the pilot reported that he now suspected that the tail rotor drive shaft became disengaged, and caused the accident. The forward tail rotor shaft assembly, and a portion of the adjoining rear tail rotor drive shaft were examined by the NTSB Materials Laboratory for inspection. The inspection discovered no evidence of an in-flight disengagement of the tail rotor drive shaft assembly prior to impact.

On March 30, 1998, about 1130 Alaska standard time, a skid equipped Aerospatiale AS-350B helicopter, N158EH, crashed during landing at the Soldotna Airport, Soldotna, Alaska. The helicopter was being operated as a visual flight rules (VFR) local area flight under Title 14 CFR Part 91 when the accident occurred. The helicopter, registered to and operated by Rotor Air Alaska, Inc., Soldotna, sustained substantial damage. The solo commercial pilot received minor injuries. Visual meteorological conditions prevailed, and VFR company flight following procedures were in effect. The flight originated about 0930 at the operator's private airstrip, Soldotna.

During the initial telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on March 30, 1998, at 1510, the pilot reported that he was in the process of practicing for a check ride that was scheduled for the next week. He said he selected an area just short of runway 25 to practice slope landings, and positioned the helicopter close to the hill in order to start the maneuver. The next thing he remembers, the helicopter had rolled to its left, and was upside down and on top of the hill that he was attempting to land beside.

On March 31, 1998, about 1500, the pilot contacted the NTSB investigator-in-charge and reported that he now suspected that the tail rotor drive shaft became disengaged, causing the accident. In his written statement to the NTSB dated April 4, 1998, he wrote: "Upon approach to landing at 10 to 15 feet above ground level and approximately 8 to 10 knots forward speed, at a high power setting, going into hover flight, the aircraft turned violently to the left going 90 degrees nose down, and landed hard, inverted. The aircraft acted as if the tail rotor drive line failed."

The forward tail rotor drive shaft assembly, and a portion of the adjoining rear tail rotor drive shaft assembly, were retained by the NTSB investigator-in-charge, and sent to the NTSB Materials Laboratory for examination. A metallurgical examination conducted by NTSB laboratory personnel discovered no evidence of an in-flight disengagement of the tail rotor drive shaft assembly prior to impact.