What happened
Following two application runs, the pilot apparently decided to shorten the standard race-track pattern by initiating the inbound turn directly into a canyon. During this maneuver, the aircraft was observed climbing clear of the canyon wall as it neared the completion of the turn. At this point, the load was jettisoned from the aircraft.
Immediately after the load was released, the aircraft descended sharply. It entered a second, narrower canyon just short of an object crop situated on a plateau. The aircraft subsequently impacted the terrain. An intense ground fire occurred after the impact and consumed the non-metallic structure of the aircraft.
The investigation
Investigation of the wreckage revealed that the aircraft impacted with high vertical forces and little forward momentum. Examination of the airframe showed no evidence of any malfunction or failure in the aircraft structure, systems, or powerplant prior to the collision.