On July 9, 1983, a Hughes 369HS (registration N500PA) operated by Pro Flight Air, Inc. was involved in an aviation accident near Springfield, MO. Investigators recorded the probable cause as: The pilot's failure to maintain proper rotor RPM during the recovery, which resulted in a hard landing and subsequent main rotor strike to the tail boom. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter sustained main rotor strike to the tail boom after a hard, tail-first touchdown during a practice autorotation recovery.
What happened
The pilot reported conducting a practice autorotation maneuver that included a full-power recovery. During the subsequent landing phase, the aircraft touched down with significant force, striking the ground tail-first before rocking forward. Although the helicopter remained upright throughout the event, the main rotors struck the tail boom as the airframe moved forward upon impact.
The investigation
The physical evidence confirmed damage to the tail boom consistent with contact from the main rotor blades. The sequence of events described by the pilot aligned with the observed structural deformation.
Probable cause
The pilot's failure to maintain proper rotor RPM during the recovery, which resulted in a hard landing and subsequent main rotor strike to the tail boom.