What happened
A certificated private pilot, accompanied by one passenger, was departing from an 800-foot long airstrip when the aircraft's engine began to run rough and lose power. According to a witness, the pilot attempted to turn the airplane around in an effort to return to the airstrip. During this maneuver, the aircraft struck the surface of an open field adjacent to the airstrip.
The investigation
An FAA airworthiness inspector examined the aircraft at the accident scene and found that the airplane came to rest in an upright position. While the left wing remained attached to the fuselage, the right wing had been torn from the aircraft during the impact. Both wing fuel tanks were found to be intact and unbreached.
The investigation focused on the fuel system, noting that the fuel selector valve was set to the right fuel tank. The inspector found that the left tank was approximately 2/3 full, whereas the right tank was empty. A neighbor who assisted rescue personnel reported that while moving the severed right wing away from the fuselage, he observed that the right wing fuel tank was empty and there were no visible signs of post-accident spillage. Additionally, an Alaska State Trooper inspected the right wing fuel cap and confirmed that the right wing fuel tank contained no fuel.
Findings
The investigation determined that the cause of the engine power loss was fuel exhaustion in the right wing tank.