What happened
The accident occurred while the pilot was conducting practice landings. Following touchdown, as the forward momentum of the aircraft decreased, the pilot observed the helicopter pitching slightly nose-down. In response to this attitude change, the pilot instinctively applied aft cyclic pressure. This input caused the main rotor blades to flex downward, resulting in them striking and severing the tail cone.
The investigation
An examination of the incident revealed no evidence of mechanical malfunction or pre-existing system failures that contributed to the event. The damage was consistent with the pilot's description of the rotor blade contact during the landing rollout phase.
Findings
The primary factor in this accident was the pilot's control input during the landing flare and rollout. The application of aft cyclic pressure while the aircraft was on the ground or just leaving the surface caused excessive downward flexing of the main rotor blades. This mechanical interaction led to the structural failure of the tail cone area. No other contributing factors were identified.
Safety message
Pilots should be aware that control inputs during the transition from flight to ground contact can have significant consequences on aircraft geometry. Understanding the specific clearance limits and flex characteristics of the rotor system is critical during the final phase of landing operations.