Accident Overview
An air tanker conducting firefighting operations collided with trees and impacted terrain, resulting in a post-crash fire. The aircraft had completed a dry pass over the fire zone before circling to execute a second pass and release 2,450 gallons of retardant. Witnesses observed the airplane in a nose-low, right-wing-low attitude as it struck trees. Upon ground impact, the aircraft exploded and burned.
Investigation Findings
The investigation found no evidence of preimpact failure or malfunction of the airframe, engines, propellers, or flight controls. The flight crew consisted of a captain in the right seat and a first officer—an initial attack trainee pilot—in the left seat. Toxicology tests performed on the first officer revealed the presence of antihistamines: 0.031 µg/ml brompheniramine and 0.011 µg/ml chlorpheniramine in kidney fluid, and 0.142 µg/ml brompheniramine and 0.072 µg/ml chlorpheniramine in liver fluid. Both medications are over-the-counter antihistamines known to have sedative effects.
Probable Cause
The official probable cause was determined to be the failure of the copilot to maintain both lateral and vertical clearance from the trees, and the failure of the captain to provide adequate supervision of the flight.