What happened
Following a landing, the pilot began taxiing backward along a beach surface. While attempting to execute a turn during this maneuver, the aircraft's nose gear suddenly collapsed. The event occurred without warning prior to the structural failure.
The investigation
Upon examining the aircraft after the incident, the pilot identified the root cause of the collapse. A bolt located within the nose gear steering mechanism had failed. Examination indicated that the failure was due to excessive wear on the component over time.
Findings
The worn bolt allowed the nose gear assembly to over-rotate beyond its normal limits during the turn. This excessive rotation subjected the landing gear structure to severe side loads, which exceeded the design tolerances and resulted in the collapse of the nose gear.