After an uneventful cross-country flight in a Piper Cherokee, the pilot began the landing descent into Rock Springs, Wyo., by reducing engine power.
When the plane approached the base leg of the traffic pattern, he performed the landing checklist, which included switching the fuel selector valve to the left tip tank. While turning the base to final leg of the traffic pattern, he decided that he was too low and applied full power to stop the descent.
The engine did not respond, but instead lost power. The pilot made a forced landing in rough terrain. The Piper went through a fence and hit a berm, substantially damaging both wings.
Data extracted from the engine monitor, as well as the minimal quantities of fuel recovered from the fuel system, were consistent with a fuel starvation event.
After the accident, the pilot told investigators that he may have inadvertently starved the engine of fuel during the approach by turning the fuel selector valve beyond its left tip tank travel limit toward its OFF position. The fuel selector lever was fitted with an interlock mechanism to prevent a pilot from inadvertently shutting off the fuel in this manner. However, examination revealed that the mechanism had shifted and the fuel selector lever could be moved to a position between the left tip tank and the OFF detent without engaging the interlock, which could result in an interruption of fuel flow to the engine.
The NTSB attributed the accident to the pilot’s inadvertent movement of the fuel selector valve beyond its tank detent, which resulted in a total loss of engine power due to fuel starvation. Contributing to the accident was the failure of the fuel selector interlock mechanism.
NTSB Identification: WPR13LA094