Accident Overview
A helicopter experienced a total loss of engine power while cruising between 200 and 300 feet above ground level at an airspeed of 100 knots. The pilot reported that the engine noise resembled the whining sound associated with a shutdown mode. The pilot entered an autorotation and landed in an open field approximately 0.5 miles from the intended airstrip.
Accident Site Examination
Examination of the accident site revealed that the helicopter touched down with forward speed, creating depressions in the soft ground over a distance of 25 to 30 feet. The helicopter subsequently rolled onto its side, and a main rotor blade severed the tail boom. Tail rotor blade and drive shaft components separated from the helicopter and were found 200 feet from the main wreckage.
Maintenance History
The last annual inspection was performed 6 months prior to the accident flight, and the aircraft had flown 16.9 hours since then. Additionally, the last compressor wash was performed approximately 2 months before the flight, with 8 hours of operation since that maintenance.
Engine Examination
Postaccident examination of the engine revealed accumulated nozzle port debris and dirty compressor blades and vanes. During a test run, the engine flamed out on the first attempt. In subsequent tests, it produced power 7.8 percent below specifications.