What happened
The pilot reported that the helicopter's collective control system did not respond appropriately when an input was made to level off following a descent. This maneuver was part of a routine agricultural swath run. The failure in the control mechanism prevented the aircraft from maintaining the desired altitude profile.
The investigation
Post-accident examination revealed extensive fire and impact damage to the helicopter, complicating the initial assessment. Despite the severity of the destruction, investigators were able to identify specific mechanical failures within the flight control system. A broken rod end was located in the collective control assembly.
Findings
Forensic analysis of the failed component indicated that the rod end had separated due to ductile overstress. This mechanical failure in the collective control system was the primary factor preventing the pilot from executing the necessary climb input to level off.
fuel exhaustion is not cited; the cause is mechanical.
Safety message
Regular inspection of flight control linkages and rod ends is critical to detect signs of fatigue or wear before catastrophic failure occurs, particularly in helicopters used for agricultural operations which subject airframes to significant vibration and stress.