What happened
The flight departed under instrument flight rules with full fuel tanks. For approximately one hour, the left main fuel tank was utilized before the selector was switched to the right main tank. Shortly before initiating a descent, while still drawing from the right main tank, the engine ceased operation. The pilot attempted to restart the engine by switching fuel tanks but was unsuccessful.
Visual conditions were encountered at 1,800 feet, allowing the pilot to identify a small clearing as the most suitable area for an emergency landing. As the aircraft approached the ground, the right front passenger unlocked her seatbelt while the cabin door was being unlocked. The aircraft was initially heading toward a house beyond the clearing. To avoid this structure, the pilot deliberately struck a tree with the left wing to alter the trajectory.
The investigation
A post-accident examination revealed critical maintenance discrepancies. A rudder connector located within the right vent line had deteriorated, effectively blocking the fuel vent. Additionally, the rudder flapper inside the vented fuel cap was stuck. These mechanical failures prevented proper fuel flow and ventilation.
The investigation also highlighted procedural failures at the maintenance facility. The owner was utilizing outdated manuals that did not require the inspection of vent hoses. At the time of the accident, the fuel selector was found in the right main position, though the pilot remained unsure of how long or how she had positioned the selector during the attempted engine restart.
Findings
The primary factors contributing to this incident were mechanical failure and inadequate maintenance procedures. The deteriorated rudder connector blocked the fuel vent, leading to engine starvation. The stuck rudder flapper in the fuel cap further exacerbated the issue. The use of outdated maintenance manuals by the facility failed to identify these critical inspection points. The passenger's decision to unbuckle her seatbelt prior to impact significantly increased the severity of her injuries.
Safety message
This accident underscores the importance of using current, manufacturer-approved maintenance manuals. Regular inspection of fuel vent systems and caps is essential to prevent blockages that can lead to engine failure. Pilots must ensure all occupants remain seated with seatbelts fastened until the aircraft has come to a complete stop.