Accident Overview
A commercial pilot operating a float-equipped airplane was transporting passengers to a lodge located at a remote lake. The aircraft failed to arrive at its destination, prompting a search. Two days later, the wreckage was located on the side of a box canyon at approximately 2,400 feet elevation.
Wreckage Distribution and Impact Evidence
The box canyon is oriented roughly east–west. The wreckage was scattered over a debris field about 100 feet long on the north flank of the canyon. Investigators noted ground scars and debris distribution consistent with the airplane striking terrain while in a steep left bank. The geometry indicated the aircraft was executing a turn to reverse direction at the time of impact.
Mechanical Examination
No evidence of any preimpact mechanical anomalies was found. The airplane's systems and structure showed no indications of failure prior to the collision.
Probable Cause and Contributing Factor
The official probable cause of the accident was the pilot's failure to maintain clearance from terrain while maneuvering inside a box/blind canyon, resulting in an in-flight collision with terrain. A contributing factor was the box/blind canyon itself.