Accident Sequence
According to the pilot's report, the flight was uneventful until the approach to the airport. While on final approach to runway 22, the pilot was unable to see the runway or surrounding area due to the sun's alignment and decided to abort the landing and initiate a go-around. Shortly after applying power and raising the landing gear, the engine sputtered and lost power. With limited visibility from the sun glare, the pilot attempted to prevent a stall during the forced landing. The airplane subsequently impacted terrain.
Post-Accident Examination
Examination of the airframe revealed that both the left and right wings sustained substantial damage. The right fuel tank was intact and contained a significant amount of fuel, while all remaining fuel tanks were breached. The engine was removed from the airframe and installed on an engine run test stand, where it successfully ran at various power settings with no anomalies noted.
Fuel Selector Valve Testing
The fuel selector valve was removed from the airframe and examined. The valve shaft was found to be bent. Manual activation by hand produced positive engagement in all positions. The valve was then placed on a test bench and functionally tested in accordance with Navion Service Bulletin 106. Within one minute of applying 24 inches of vacuum pressure, an unspecified amount in excess of 20 inches of pressure was lost. According to the type certificate holder, the maximum specified loss is one inch. Both internal and external leaking were observed during the bench test. The fuel selector valve was disassembled and visually inspected, with no anomalies noted.
Timing
The official sunset was recorded as 48 minutes after the approximate time of the accident, and the end of civil twilight was 75 minutes after the approximate time of the accident.