What happened
Operating under the callsign Tanker 04, the Air Tractor departed from Missoula to perform aerial firefighting operations. During the mission, the crew encountered technical difficulties involving the malfunction of the aircraft's retardant-release doors. While attempting to manage this mechanical issue, the aircraft entered a narrow box canyon near Mt Squaw, located approximately 20 miles northwest of Missoula Airport. The aircraft subsequently impacted the slope of the mountain. The impact resulted in the total destruction of the aircraft and two fatalities.
Findings
Investigations into the crash indicate that the crew became preoccupied with the malfunctioning release doors. This fixation on the mechanical failure prevented the pilots from recognizing that the aircraft was flying into a restricted canyon area, leading to the fatal collision with the terrain.