Incident Overview
On April 10, 2012, at approximately 1315 Pacific daylight time, a Willerton Vans RV-6A, registration N6000Z, sustained substantial damage to its firewall during a precautionary landing at Blue Ribbon Airport (WN29) in Sequim, Washington. The aircraft was operated by the private pilot under 14 Code of Federal Regulations Part 91 for a local instructional flight. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight originated from Sequim Valley Airport (W28) at 1300.
Flight and Landing Sequence
According to the private pilot, while climbing through about 4,000 feet, both the certified flight instructor (CFI) and the pilot observed fuel leaking from the right wing fuel cap. They decided to initiate a precautionary landing at WN29. Following a normal approach, the airplane struck the runway with excessive force, causing the propeller to strike the ground. The impact resulted in substantial damage to the firewall. Neither the CFI nor the private pilot reported any injuries.
Mechanical Assessment
The private pilot stated that there were no mechanical malfunctions or failures that would have precluded normal operations. A post-accident examination conducted by a Federal Aviation Administration (FAA) inspector revealed that the stopper-type fuel cap was found in the locked position; however, it was loose and not properly secured within the filler port.
Conclusion
The investigation determined that the fuel cap was not properly secured, leading to fuel leakage during climb. The subsequent precautionary landing was executed, but a hard touchdown resulted in structural damage to the aircraft.