Primary finding
Probable cause
The inadvertent dynamic rollover of the helicopter after the helicopter became airborne during an engine run-up.
Investigator assessment
Analysis narrative
The helicopter rolled over onto its left side during an engine run-up. The student pilot reported the helicopter became airborne during the run-up. He attempted to recover from the inadvertent lift-off by lowering the collective to the full down position, but the helicopter was already rolling to the left. The student pilot remarked, "It is this pilot's opinion that the aircraft experienced a dynamic roll over condition." He reported he did not intend to become airborne.
Source record
Factual narrative
On July 11, 2003, at 1845 central daylight time, an amateur-built Spiker Rotorway 162F helicopter, N444T, sustained minor damage when it rolled over on its left side during an engine run-up at Creve Coeur Airport, St. Louis, Missouri. The pilot was not injured. Visual meteorological conditions prevailed during the engine run-up. The student pilot reported he was performing an engine run-up to check the engine and drive train. The pilot stated, "After run-up with collective throttle at about 100% the aircraft became airborne." The pilot reported he "immediately" lowered the collective to the full down position, but the helicopter was already beginning a roll to the left. The helicopter rotated onto its left side and came to a stop. The pilot remarked, "It is this pilot's opinion that the aircraft experienced a dynamic roll over condition." The pilot reported he did not intend to become airborne. The pilot reported no mechanical malfunctions or defects prior to the accident.