On April 15, 2012, about 1730 eastern daylight time, an experimental, amateur-built Willoughby Streak Shadow, N2828W, was substantially damaged following a loss of engine power and collision with terrain near Salem, West Virginia. The airline transport pilot was seriously injured. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed and no flight plan was filed. The local flight was originating at the time of the accident.
A Federal Aviation Administration inspector responded to the accident site and examined the wreckage. Structural damage to the wings was evident. The fuel tank was ruptured. No fuel was observed in the in-line fuel filter. The wreckage was recovered to a storage facility where a more detailed examination was conducted.
The pilot stated that he was flying the aircraft for the first time since it was “rebuilt” after an accident two years prior. After ground operations, he took off to the west from the grass airstrip at his residence. Shortly after takeoff, above tree top level, approximately 150 feet above the ground, the engine sputtered and stopped running. He attempted a left turn to maneuver for an open area to perform a forced landing. The aircraft collided with trees on a hill adjacent to the airstrip. He did not recall any events after the collision.
The engine and fuel system were examined at the pilot’s hangar on August 14, 2012. Partial disassembly of the engine revealed that the pistons exhibited severe scuffing and scoring, consistent with a seizure event. Inspection of the fuel lines revealed that there was a fuel flow transducer, manufactured by MGL, installed in-line, with a 2 millimeter (mm) jet. The fuel lines were secured with plastic tie wraps and in one area no fuel line clamp was used on a fitting.
The fuel flow transducer was tested on another engine after the examination. A vacuum and pressure gauge were installed in the fuel system to observe any changes under various running conditions. The engine was started and ran normally up to 7,100 rpm with the fuel flow transducer installed (with the 2mm jet). Another run was attempted with a valve installed between the fuel flow transducer and the fuel pump to allow the introduction of air into the system to replicate unsecured or poorly secured fuel lines. With a small amount of air introduced while the engine was running, fuel flow dropped significantly, resulting in low fuel pressure and fluctuating rpm. After the engine run, the pistons were examined and they exhibited signs of scoring and cylinder polishing.
According to the engine manufacturer, although there was no reduction in fuel flow or rpm with a 2mm jet installed in the transducer, there should be no device installed anywhere in the fuel system that is smaller than the minimum fuel line diameter of 5mm.