WPR12LA178

The pilot reported that the airplane had been refueled before the flight and that the fuel had expanded during the day due to heat, which resulted in fuel draining from the vent. The pilot loosened the fuel caps to facilitate draining excess fuel from the tank; however, he forgot to resecure the left-side cap after he finished draining the fuel. Shortly after takeoff, the pilot reported to an air traffic controller that one of the airplane's fuel caps was not secure and requested permission to return to the airport for landing. However, the pilot did not maintain an adequate glidepath during the approach, and the airplane impacted terrain short of the runway. The pilot reported no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation. During the impact sequence, the pilot's shoulder harness webbing separated, resulting in a serious injury. Examination showed that the webbing met the original load requirements as specified by the manufacturer, and no photodegradation was evident.

The NTSB's safety alert "Check Your Restraints" notes the importance of restraint systems in preventing injuries and provides resources for inspecting restraint systems for wear and damage. The safety alert can be found at http://www.ntsb.gov/doclib/safetyalerts/SA_027.pdf. On April 21, 2012, at 1717 Pacific daylight time, N3862C, a Beechcraft Corporation A36TC, registered to Hermiston Aviation Inc. and operated by the pilot collided with terrain short of the runway at Eastern Oregon Regional Airport, Pendleton, Oregon. The commercial pilot sustained serious injuries and the two passengers were not injured. The airplane was substantially damaged. The pilot was operating the airplane under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed. According to emergency response personnel, the pilot had departed Pendleton and radioed to the air traffic control tower controller that one of the airplane's fuel caps was not secured. The pilot was returning to the airport when the airplane impacted terrain short of runway 16. The pilot stated that the airplane had been refueled prior to the flight. It was a warm day with the tank full of fuel and the heat resulted in fuel draining from the vent. The pilot loosened the fuel cap to aid in ridding the tank of the excess fuel. Upon departure, the left wing fuel cap departed from the fuel tank. As the pilot returned to land, he did not maintain an appropriate glide path during final approach and the airplane collided with terrain on the approach end of runway 16. The pilot indicated there were no mechanical malfunctions or failures during the flight, and the engine continued to operate until impact with the terrain. Post accident examination of the airplane revealed that the pilot's shoulder harness separated during the accident sequence resulting in serious injuries. The shoulder harness was dated September of 1980 and was installed when the airplane was manufactured. The pilot's shoulder harness and lap belt were examined by a metallurgist from the NTSB Materials Laboratory. The separation point on the shoulder harness belt showed that some filaments contained mushroomed ends, consistent with a relatively high loading rate. Under such conditions, the loading of the filament produces heat which softens the filament and causes it to fracture. The shoulder harness was also examined using a Fourier Transform Infrared (FTIR) spectrometer. The test was indicative of negligible photodegradation of the webbing. Additionally, the restraint system was examined at Beechcraft with a representative from the Federal Aviation Administration. Sections of the shoulder harness were tensile tested and exceeded the proof load strength of 1,666 pounds, with an ultimate static load strength of 2,500 pounds.