N14412

On June 2, 1994, at 1246 Pacific daylight time, a Bell 47D-1 helicopter, N14412, rolled over during hover at the Chino, California, airport. The aircraft was in a hover in preparation for takeoff from a helipad on the airport. The helicopter was owned and operated by Mike Zemlock Helicopters of Chino and was rented by the pilot for a local area personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed for the operation. The aircraft incurred substantial damage. The certificated private pilot, the sole occupant, was not injured. The flight was originating at the time of the occurrence.

In a telephone interview, the pilot reported that she lifted into a hover in preparation for takeoff and the helicopter began a pilot inducted oscillation due to heavy cyclic control forces. The pilot stated that she overcompensated on the controls and the helicopter rolled over. The pilot reported that during the run-up procedure she disengaged the hydraulic system to check the rotor tip path plane and forgot to reengage the system prior to lifting into a hover. The pilot said there was no mechanical malfunction or failure of any system.