What happened
On the day of the accident, an air tanker was conducting its tenth flight of the day, serving as a training mission for pilots preparing for the upcoming USFS fire season. The crew, which included the captain, the copelot, and the company's Chief Pilot acting as an instructor, was performing practice water drops over rugged mountains north of the airport. Prior to this specific flight, the aircraft had completed nine successful missions with no reported mechanical issues.
Radar tracking showed the aircraft flying a northeast-southwest racetrack pattern. During the final minute of the flight, the aircraft was traveling up a valley on the northeast leg of the pattern. Within the final 36 seconds, the flight path began drifting toward the rising terrain on the eastern side of the valley. The final radar observations placed the aircraft at an altitude of less than 100 feet above the ground. The aircraft subsequently entered a left descending turn, impacting the terrain at an elevation of approximately 2,450 feet msl. The impact occurred with the left wingtip striking the ground first, followed by a severe post-crash fire. There were three fatalities as all crew members were aboard the aircraft.
Findings
Investigation of the wreckage site showed that the aircraft was severely fragmented, but all four engines and propellers were recovered. The engines showed no evidence of in-flight fire, uncontained failures, or pre-impact malfunctions; instrumentation indicated all engines were producing approximately 2,200 shaft horsepower at the moment of impact. Maintenance records showed no chronic issues or anomalies that would have contributed to the crash. No evidence was found of pre-existing structural failure or impact with foreign objects. The aircraft was not equipped with a cockpit voice recorder or flight data recorder. The cause of the in-flight collision with terrain could not be determined.