Accident Narrative
According to the pilot, prior to liftoff he verified freedom of controls and the absence of warning or caution lights. The cockpit was illuminated only by very dim instrument and navigation-radio lights; the pilot chose not to activate the searchlight, landing light, or taxi lights. The moon was full, directly overhead, and bright.
As the helicopter began a vertical ascent with light skids, the nose yawed left. The pilot applied right pedal input, but it felt stuck or blocked. Within one to two seconds, the aircraft commenced a right roll. The pilot applied left cyclic pressure, but it also seemed extremely stiff or stuck. The helicopter subsequently rolled over onto its right side, sustaining substantial damage.
Weather and Environmental Conditions
At the time of the accident, weather was reported as clear skies with 10 miles visibility and winds from 170 degrees at 4 knots. The helipad was situated in a former gravel pit. The surrounding terrain consisted of pale white-colored sandy soil that rose above the pad on all quadrants.
Examination Findings
An examination of the helicopter's flight controls and other systems revealed no anomalies. Ground scars and paint transfers on the pad were consistent with the ground resonance spring on the right skid making contact with the pad surface. The pattern of the ground scars indicated that the helicopter was moving laterally and aft when the spring first contacted the pad, which subsequently initiated a dynamic rollover of the aircraft.