What happened
The pilot departed on a visual flight rules (VFR) flight plan carrying a litter patient and three additional passengers. During the initial thirty minutes of flight, the right main fuel tank was utilized. The pilot then switched the fuel selector to the left main tank while en route. As the destination weather failed to meet VFR forecasts, an instrument flight rules (IFR) flight plan was filed.
Before descending into the clouds for an instrument landing system (ILS) approach, the pilot performed a before-landing check and switched the fuel selector back to the right main tank. The engine lost power abruptly during the approach. The pilot believed he had inadvertently switched to the right tip tank and then back to the right main tank while attempting to restart the engine.
The investigation
Upon recovery, the fuel selector was found positioned to the left tank, which contained approximately three pints of fuel remaining. This indicates the pilot likely switched away from the right main tank during the restart attempt without realizing it.
Findings
The aircraft struck trees while the pilot attempted to maneuver to a clearing after breaking out of the clouds. The primary factor was fuel exhaustion resulting from improper fuel management during the approach and engine restart sequence.