WPR14FA218

A total loss of engine power due to fuel starvation because of a blocked fuel line that resulted from the pilot’s improper maintenance practices and the pilot’s subsequent failure to maintain adequate airspeed while attempting a forced landing, which led to the airplane exceeding its critical angle-of-attack and experiencing an aerodynamic stall.

The pilot, who was also the builder of the experimental kit airplane, departed for a cross-country flight from his home airport. The passenger reported that, following a normal departure, the airplane continued the takeoff climb through some cloud wisps and ascended above a lower cloud cover with an overcast layer above. Suddenly, the engine experienced a total loss of power. The pilot maneuvered the airplane toward the closest airport, but, when he realized that the airplane would not be able to glide to the airport, he attempted to make an off-airport landing. The airplane stalled and then collided with terrain in an open area of a paper mill. Ground scar analysis and wreckage fragmentation revealed that the airplane descended in a steep, near-vertical, nose-down, left-wing-down attitude before it impacted terrain. The pilot installed a fuel flow transducer about 2 to 3 weeks before the accident and used heavy applications of room temperature vulcanization (RTV) silicone to seal the fuel lines. A friend of the pilot, who was also a mechanic, reported that he had observed the pilot about a year earlier using heavy applications of RTV silicone to seal parts during a condition inspection and that he had mentioned to the pilot that this was an improper practice. A bead of RTV silicone was found in the fuel line, and it is likely that it blocked the inlet of the transducer and starved the engine of fuel. Additionally, subsequent to the loss of engine power, the pilot failed to maintain sufficient airspeed while maneuvering to locate a suitable off-airport landing site and flew the airplane beyond its critical angle-of-attack, which resulted in a stall and loss of airplane control.

No record exists of the pilot, or a pilot using the airplane's registration number, contacting any Air Traffic Control tower, or Common Traffic Advisory Frequency, during the duration of the flight. A detailed examination report with accompanying pictures is contained in the public docket for this accident. Airframe The main wreckage cockpit area was open, with the engine and firewall twisted toward the right wing. Most of the upper cabin area had broken free from the airframe; the section that remained attached consisted of fiberglass on the aft right side about four feet forward of the bulkhead. The throttle, propeller, and mixture control levers were bent in their respective control quadrant, which was consistent with them being in the full-forward position at the time of impact. The right wing remained attached to the fuselage at all attach points, and the flap and aileron control surfaces remained attached to their respective hinges. The right wingtip aft section and fragments of a blue/green lens were located just below the right wing adjacent to a concrete divider. Around the divider was evidence of blithe, and numerous areas of vegetation had been crushed, which was consistent with fuel exposure. The right wing sustained major skin deformation crushing from the aft outboard tip to about three feet inboard; this was consistent with the size and orientation of the concrete divider that was located immediately below it. The wing sustained aft crush deformation, with the bottom leading edge skin folded into itself, giving it an accordion-type appearance. The crush was nearly uniform through the entire length of the wing. The leading edge displayed characteristics consistent with hydrodynamic deformation. Control continuity was confirmed in the right wing up to the crush deformation in the cockpit area. The left wing was attached to the fuselage at all attach points, and the flap and aileron control services remained attached to their respective hinges. The left flap was attached to the two inboard respective hinges and creased at the center hinge in an upward crush. The left aileron was found wedged underneath the main wreckage cockpit area. The leading edge displayed characteristics consistent with hydrodynamic deformation. Control continuity was confirmed in the left wing up to the crush deformation in the cockpit area. The right and left horizontal stabilizers and elevator remained intact with creasing noted on some of the surfaces; continuity to the cockpit was established. The vertical stabilizer and rudder remained intact with a slight crease on the rudder control surface about six inches from the top and consisted of a four inch bend. The rudder was attached to its control cables and continuous to the rudder pedals and secured. The elevator was attached to the push-pull tube, which was continuous up to the cockpit area. Both control sticks were attached and safetied. Powerplant The engine mount support tubes were severed by investigators between the engine and firewall, which essentially separated the engine from the airframe. An external visual examination of the engine revealed that it had sustained crush damage to the bottom of the crankcase, with the majority of damage to the left side. There were dark stains to the left of the upper spark plug holes, which was consistent with oil staining. The spark plugs were removed and no mechanical damage was noted; the electrodes and posts exhibited a light ash white coloration, which according to the Lycoming representative was consistent with a very lean operation(s). The ignition harnesses were attached from both magnetos to their respective spark plugs. The right magneto was secured to its respective mounting pad. Upon rotation, investigators observed spark produced at all posts. The left magneto sustained varying degrees of damage that rendered the unit inoperative and therefore, could not be functionally tested. The crankshaft was rotated by hand utilizing the propeller. The crankshaft was free and easy to rotate in both directions. "Thumb" compression was observed in proper order on all six cylinders. The complete valve train was observed to operate in proper order, and appeared to be free of any pre-mishap mechanical malfunction. Normal in uniform "lift action" was observed at each rocker assembly. Clean, uncontaminated oil was observed at all six rockerbox areas. Mechanical continuity was established throughout the rotating group, valve train and accessory section during hand rotation of the crankshaft. The cylinders' combustion chambers were examined through the spark plug holes utilizing a lighted borescope. The combustion chambers remained mechanically undamaged, and there was no evidence of foreign object ingestion. The valves were intact and undamaged. There was no evidence of valve to piston face contact. The chambers and valve faces all displayed little combustion signatures and there was a whitish light ash coloration; the exhaust valve faces were slightly darker, exhibiting a white-orange-coloration. This white residue/soot was additionally seen throughout the remainder of the exhaust system. The Hartzell propeller, model HC-C2YK-1BF, serial number 40546, remained attached to the engine crankshaft. All propeller mounting bolts remained in the hub and exhibited no signatures consistent with shear stress. The propeller blades remained attached at the hub. The spinner was displaced from the propeller hub. The propeller blades were straight and did not show any evidence of rotational forces applied at the crankshaft at the time of impact. Removal of the propeller governor disclosed that the screen was free of contaminants. Fuel System The fuel selector was found with the handle pointing to the "LEFT" tank position. Later, it was confirmed by a friend of the pilot that the handle was installed with the handle giving a reverse indication, which meant that the fuel would be selected in the "OFF" position. The position of the fuel selector valve, manufactured by Andair, LTD, was off with both lines shut off. The selector was found in several pieces: the handle (which was still attached to the airframe), the extender (which was located loosely in the wreckage adjacent to the pilot seat), the upper coupling (which had broken free from its remaining core and was found loosely in the wreckage), the valve (which was found loosely in the wreckage near the firewall). There was no evidence that the extender had been safetied to either couplings. The fuel filter, manufactured by Airflow Performance, was disassembled and the screen was found to be clean. Investigators located a Facet automotive electric fuel pump within the wreckage and upon supplying power source the pump was found to activate. The transducer, a FloScan 201 A-6 flow sensor (s/n 179922), was found in the wreckage. The fuel line from the electric fuel-pump to the transducer was separated at the pump's B-nut fitting as a result of post impact forces. An approximate one-inch portion of the line remained attached on the inlet side of the transducer and the end was crimped tightly together and bent. Investigators pried open the crimped section and found an oval bead of red/orange RTV that measured about 0.25 inches in length. According to the manufacture, the inlet hole (metering orifice) is reamed to approximately 0.114 to 0.116 inches. Removal of both the inlet and outlet fittings revealed that RTV was in the threads of both the nipples and the surrounding casing. The upper cap section and mounts of the gascolator remained attached to the firewall; the metal bowl was located under the right wing and there was no evidence it had been secured/safetied to its attachment arm/ thumb-tightening screw; the screen was additionally found loose under the right wing and was clean. The engine-driven fuel pump was displaced from the engine. Disassembly of the fuel pump revealed that is was free