What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(.4)The pilot and mechanic departed on a maintenance test flight after completing the installation of an overhauled engine. They performed ground engine runs and two short legs of the test flight. After each leg, the helicopter was shut down and the engine was checked for leaks. The pilot departed on the third leg after official sunset, and after climbing to approximately 1,700 feet, the pilot closed the throttle, then entered autorotation. The mechanic said the engine and rotor RPM decayed simultaneously and then the engine stopped running. During descent, the pilot attempted to restart the engine without success. The autorotation was terminated with a hard landing. Examination of the engine revealed no anomalies and it ran to rated power in a test cell. While operating at full RPM, the throttle was moved rapidly to the flight idle position. The engine exhibited a smooth reduction in RPM to the idle power setting with no interruption. An FAA helicopter handbook stated to begin an autorotation, the collective should be placed full down maintain cruise RPM with the throttle. Then decrease the throttle and adjust it to keep the engine RPM 'well above normal idling speed.' (-23) aircraft left lamell lumber yard after approx. 30 mins of grnd runs to check over engine r&r. departed to north and made a landing in plowed field off of rt 128 (behind hallett's farm) and pilot & mech passenger ckd over installation for leaks. Then departed vertically racing north to approx 1500' AGL. Pilot intended to do auto rotation with power recovery. On shutting throttle, engine quit- unable to restart- unsuccessful auto-rotation attempt.
As the FAA filed it
(.4)THE PILOT AND MECHANIC DEPARTED ON A MAINTENANCE TEST FLIGHT AFTER COMPLETING THE INSTALLATION OF AN OVERHAULED ENGINE. THEY PERFORMED GROUND ENGINE RUNS AND TWO SHORT LEGS OF THE TEST FLIGHT. AFTER EACH LEG, THE HELICOPTER WAS SHUT DOWN AND THE ENGINE WAS CHECKED FOR LEAKS. THE PILOT DEPARTED ON THE THIRD LEG AFTER OFFICIAL SUNSET, AND AFTER CLIMBING TO APPROXIMATELY 1,700 FEET, THE PILOT CLOSED THE THROTTLE, THEN ENTERED AUTOROTATION. THE MECHANIC SAID THE ENGINE AND ROTOR RPM DECAYED SIMULTANEOUSLY AND THEN THE ENGINE STOPPED RUNNING. DURING DESCENT, THE PILOT ATTEMPTED TO RESTART THE ENGINE WITHOUT SUCCESS. THE AUTOROTATION WAS TERMINATED WITH A HARD LANDING. EXAMINATION OF THE ENGINE REVEALED NO ANOMALIES AND IT RAN TO RATED POWER IN A TEST CELL. WHILE OPERATING AT FULL RPM, THE THROTTLE WAS MOVED RAPIDLY TO THE FLIGHT IDLE POSITION. THE ENGINE EXHIBITED A SMOOTH REDUCTION IN RPM TO THE IDLE POWER SETTING WITH NO INTERRUPTION. AN FAA HELICOPTER HANDBOOK STATED TO BEGIN AN AUTOROTATION, THE COLLECTIVE SHOULD BE PLACED FULL DOWN MAINTAIN CRUISE RPM WITH THE THROTTLE. THEN DECREASE THE THROTTLE AND ADJUST IT TO KEEP THE ENGINE RPM 'WELL ABOVE NORMAL IDLING SPEED.' (-23) AIRCRAFT LEFT LAMELL LUMBER YARD AFTER APPROX. 30 MINS OF GRND RUNS TO CHECK OVER ENGINE R&R. DEPARTED TO NORTH AND MADE A LANDING IN PLOWED FIELD OFF OF RT 128 (BEHIND HALLETT'S FARM) AND PILOT & MECH PASSENGER CKD OVER INSTALLATION FOR LEAKS. THEN DEPARTED VERTICALLY RACING NORTH TO APPROX 1500' AGL. PILOT INTENDED TO DO AUTO ROTATION WITH POWER RECOVERY. ON SHUTTING THROTTLE, ENGINE QUIT- UNABLE TO RESTART- UNSUCCESSFUL AUTO-ROTATION ATTEMPT.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.