What happened
The accident occurred during the landing phase of flight when the helicopter's tail rotor made contact with a forest service sign post. The pilot had visual awareness of the sign post prior to touchdown but elected to land in close proximity to it to facilitate easier refueling operations. The aircraft touched down on a sloped surface, which caused the nose of the helicopter to begin sliding downslope.
As the slide continued, the pilot attempted to raise the collective pitch to lift the aircraft off the ground. However, the nose continued to yaw uncontrollably despite the input. This uncontrolled yawing motion brought the tail rotor assembly into contact with the sign post. The impact caused the helicopter to yaw further and subsequently roll over onto its side.
The investigation
Examination of the wreckage confirmed that the primary damage was sustained by the tail rotor system due to its collision with the forest service sign post. The mechanical failure was directly linked to the ground contact event rather than an in-flight mechanical malfunction. No evidence was found suggesting pre-impact engine failure or loss of control prior to the landing attempt.
Findings
The sequence of events indicates that the decision to land near a fixed object for convenience contributed significantly to the accident. The combination of a sloped landing area and the proximity of the sign post created a hazardous situation where the tail rotor's clearance was compromised. The pilot's awareness of the obstacle did not prevent the accident because the landing position was chosen specifically for refueling access rather than safety.
Safety message
Pilots should avoid landing near fixed obstacles, such as sign posts or trees, even for convenience. Terrain slope and object proximity can severely limit tail rotor clearance and control authority during ground operations.