On April 7, 1991, a Hughes 369D (registration N1109Q) was involved in an aviation accident near Yerington, NV. Investigators recorded the probable cause as: THE PILOT'S EXCESSIVE AIRSPEED AND RATE OF DESCENT ON FINAL APPROACH TO LAND, AND SUBSEQUENT LOSS OF ROTOR RPM WHILE ATTEMPTING TO FLARE. THE DITCH WAS A RELATED FACTOR. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A Hughes 369D helicopter sustained substantial damage after a hard landing and rollover, following reports of a fast approach and low rotor RPM warning activation.
What happened
A Hughes 369D helicopter experienced a hard landing that resulted in the aircraft rolling over. During the final phase of the flight, one of the passengers reported that the landing approach was conducted at an excessive speed. As the pilot attempted to arrest the descent by applying power, a distinct noise was heard. This event was immediately followed by the activation of the low rotor RPM warning system. Shortly thereafter, the right skid of the helicopter contacted a ditch, causing the aircraft to roll over.
The investigation
The available source material does not provide specific details regarding mechanical examinations or post-accident findings beyond the sequence of events described above.