Accident Sequence
Shortly after takeoff, while using water/alcohol injection, the pilot observed that the N2 turbine speed indication had gone to the top of the gauge. In response, he rolled off the throttle to reduce the N2 gauge reading and simultaneously looked for a place to land. Believing there was insufficient altitude for an autorotation, the pilot continued the approach. Subsequently, the helicopter touched down hard and came to rest with extensive damage.
Post-Accident Examination
A post-accident examination of the airframe, flight controls, and fuel system revealed no preimpact failures. The water/alcohol solution was tested and found to contain 66.5% methanol and 33.5% water. The specifications required 33.5% methanol and 66.5% water. However, Allison engine personnel stated that the high level of methanol would not have affected engine performance.
Engine and Instrument Testing
During a post-accident test, the engine operated to full power with no evidence of failure or malfunction. Testing of the engine instruments revealed that the N2 gauge was providing a faulty indication. The other engine instruments operated normally after the accident.