What happened
The incident occurred while a non-rated private pilot was operating a helicopter within the traffic pattern. The primary objective of the flight was to practice power recovery autorotations. During the third or fourth attempt at this maneuver, the pilot/owner flared the aircraft excessively. This action caused the tail rotor blades to strike the ground. The impact resulted in the separation of the tail rotor system. Consequently, the helicopter rolled over, leading to substantial damage to both the main rotor system and the airframe.
The investigation
The investigation focused on the mechanical failure resulting from the ground contact. Examination confirmed that the tail rotor system separated following the strike. The damage was extensive, affecting the main rotor system and the general airframe structure. No other mechanical failures were identified as contributing factors prior to the impact.
Findings
The primary factor in this accident was the pilot's excessive flare during the power recovery autorotation practice. This maneuvering error directly led to the tail rotor blades striking the ground. The subsequent separation of the tail rotor system caused the loss of control and the rollover. The substantial damage to the main rotor system and airframe was a direct result of this sequence of events.
Safety message
Pilots practicing autorotations must maintain precise control of pitch and flare to avoid ground contact with rotating components. Excessive flare angles can lead to tail rotor strikes, which may cause catastrophic structural failure and loss of control.