Accident Sequence
After completing hover checks, the pilot initiated a takeoff through a cut in the trees. When the helicopter reached approximately 60 feet above ground level and 40 knots airspeed, a loud bang was heard. The helicopter subsequently yawed to the left, and the rotor rpm began to decay. In response, the pilot initiated an autorotation and executed a hard, steep right turn toward the only available landing area, which was located 75 yards to the right rear. The helicopter landed hard on its right skid and rolled over, coming to rest on its right side.
Engine Examination
The engine was removed and test-run. During the test run, its performance exceeded the specifications for a new engine. Afterward, the engine was partially disassembled and inspected. Investigators found indications of blood and flesh in the impeller and through the compressor air discharge tubes. This finding was consistent with other engines that had been examined and found to have ingested green tree frogs.
Pilot Preflight Inspection
The pilot reported that during the preflight inspection, he did not observe any green tree frogs.