CEN12LA648

After takeoff, about 400 feet above ground level and about 50 knots airspeed, the flight instructor reduced the throttle to idle so the student pilot could demonstrate an autorotation. The student dropped the collective to enter the autorotation, and the engine stopped producing power; the helicopter descended rapidly and landed hard. A postaccident examination of the helicopter revealed an obstructed air filter. It is likely that the student lowered the collective too quickly, which, combined with the obstructed air filter, created a rich fuel mixture and loss of engine power. The student pilot mismanaged the autorotation and the instructor did not intervene in a timely manner to prevent the hard landing.

On September 19, 2012, about 1230 central daylight time, a Hughes 269A, helicopter, N37754, performed a hard landing, following an autorotation near Mc Cool Junction, Nebraska. The certificated flight instructor (CFI) and student pilot were not injured. The helicopter sustained substantial damage to the fuselage and tail boom. The helicopter was registered to and operated by the Star City Flying Club, Lincoln, Nebraska, under the provisions of 14 Code of Federal Regulations Part 91 as an instructional flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight originated from a private airfield. According to statements taken by the responding Federal Aviation Administration inspectors, the purpose of the flight was to prepare the student pilot for an upcoming check ride. After takeoff, about 400 feet above ground level and at an airspeed on 50 knots, the CFI brought the engine back to idle to simulate a loss of engine power. The student dropped the collective and the engine quit producing power. An autorotation was initiated; however, the helicopter rapidly descended and landed hard. The tail boom was severed and the helicopter rolled over on its side. An inspection of the airframe and engine by inspectors from the FAA inspectors revealed that the air filter was approximately 80% obstructed by debris. A ground run was performed on the engine and the engine was found to have an excessively rich mixture.