What happened
The aircraft departed at approximately 10:20 bound for its destination. GPS data recovered from the site indicated that the pilot turned north and began a descent from 11,000 feet roughly 45 minutes after takeoff. The flight path showed a turn to the east followed by an approximately 13/5-degree right turn leading to ground impact.
Witnesses at a temporary firefighting landing site located a half-mile southwest of the crash site observed the aircraft flying west to east, slightly north of the helibase and roughly parallel to its axis. The witnesses noted the landing gear had extended and observed the aircraft performing a descending right turn as if attempting to line up for landing. One witness reported the aircraft was moving extremely slowly, near stall speed, while another observer noted that the aircraft appeared to stall before descending vertically into the ground.
The investigation
On-site examination determined the aircraft struck the ground at a near-vertical angle of 83 degrees, with evidence of high rotational energy in the propeller immediately before impact. The aircraft's final GPS position recorded an altitude of 5,666 feet, while the impact occurred at 5,410 feet. During the final 45-degree arc of the approach turn, the aircraft traveled over rapidly up-sloping terrain that rose more than 200 feet. The area was heavily populated with conifer trees approximately 75 feet in height, and a high-tension power line was located near the treetop level.
Post-crash examination of the aircraft revealed no evidence of powerplant malfunction or control discontinuity. An inspection of the fuel system found fuel present at the fuel flow divider, both gas caps were secured, and there was no evidence of fuel staining on the exterior of the aircraft or at the belly drain.
Findings
- The aircraft impact was near vertical at an 83-degree angle.
- The aircraft's flight path took it over terrain that was ascending rapidly.
- There were no indications of engine failure or loss of control continuity.