LaGrange, GA, USA
N488WT
JAMES KILROY PITTS MODEL 12
According to the private pilot, shortly after takeoff for a cross-country flight in the experimental, amateur-built airplane, the engine rpm "quickly dropped to idle." He verified that the electric fuel boost pump was on and switched to the auxiliary fuel tank, but the engine performance did not improve. The airplane was unable to reach the airport, so the pilot performed a forced landing in a field. During the landing, the airplane nosed down and then came to a stop, which resulted in structural damage to the airplane and serious injuries to the pilot. An examination of the fuel system revealed no evidence of fuel interruption, blockage, or contamination. Internal engine continuity was established, and the spark plug electrodes appeared normal. Continuity from the cockpit engine controls to the engine was confirmed. The throttle body, engine-driven fuel pump, and electric boost pump showed no evidence of a mechanical malfunction or failure. Although data from the electronic engine monitor confirmed that the engine rpm decreased to near idle and continued to decrease throughout the accident sequence, the reason for the partial loss of engine power could not be determined.
On April 22, 2015, about 1350 eastern daylight time, an experimental, amateur-built Kilroy Pitts Model 12, N488WT, was force landed following a partial loss of engine power after departure from LaGrange-Calloway Airport (LGC), LaGrange, Georgia. The private pilot received serious injuries and the airplane was substantially damaged. The airplane was operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. Day, visual meteorological conditions prevailed, and no flight plan was filed. The flight to Lakeland, Florida (LAL) was originating at the time of the accident. According to the pilot, he had completed an uneventful flight from Tullahoma, Tennessee (THA) to LGC and stopped at LGC for fuel. He started the engine and taxied to the active runway, which took about 15 minutes. Engine run-up was normal. Shortly after takeoff, while transitioning to climb mode, "the engine RPM quickly dropped to idle." He checked the electric boost pump on and selected the auxiliary fuel tank with no change in performance. He then moved the throttle forward and aft; the throttle felt normal and engine speed remained at idle. He was unable to return to the airport, so he elected to perform a forced landing in a field. He did not recall any events after setting up for the forced landing. An inspector with the Federal Aviation Administration FAA responded to the accident site and examined the wreckage. The wreckage site consisted of a grass field, about 500 yards southeast of the approach end of runway 31. The forward fuselage and lower wing exhibited structural damage from impact forces. The main landing gear were crushed upward, into the lower wing structure. The wooden propeller blades were broken off and splintered at the blade shanks. On June 24, 2015, the NTSB investigator-in-charge examined the wreckage at the owner's facility. The fuselage fuel tanks were removed; both were clean inside with no evidence of blockage or contamination. Both tanks were breached due to impact damage and contained no visible fuel. The main tank filler cap was secure. All fuel tank vents were clear. All fuel lines to the engine were clear. The firewall-mounted gascolator was removed and opened. It contained about two ounces of blue-colored fuel and there were no water or contaminants observed. There was an in-line fuel filter installed at the firewall; it was opened for examination and was clean and there were no contaminants inside. The engine controls were checked for continuity. All controls to the engine were intact. The throttle cable was broken at the fuel control attachment with signatures consistent with overstress. The engine-driven fuel pump was removed and disassembled. Initially, it was difficult to turn by hand; however, there was impact damage evident. Internally, it was unremarkable. The pump vanes showed no visible wear. There was no visible contamination inside the pump. The electric fuel boost pump was energized with a battery and it operated in a normal manner. The pump was then removed and disassembled; other than a small amount of thread sealant visible at the ports, it was clean inside. All internal parts were undamaged and showed no visible wear. The throttle body was removed and disassembled. Due to impact damage, an operational test of the unit was not attempted. No contamination was observed inside the unit, and there were no obstructions to air flow. The rubber diaphragm was undamaged and was in a like-new condition. Five representative spark plugs were removed and examined. The electrodes showed minimal wear and normal combustion signatures when compared to a spark plug inspection chart. The ignition harness was in an undamaged condition. The magnetos were not removed. The engine was turned through by manually by rotating the propeller hub. Continuity was confirmed through the engine to the accessory drive pads. There was no evidence of an internal failure. The airplane was equipped with an Electronics International Inc. CGR-30P primary engine monitor. The monitor recorded engine performance data that included the accident flight. The data fields recorded were cylinder head temperature (CHT), exhaust gas temperature (EGT), engine fuel flow, engine fuel pressure, engine RPM, and manifold pressure. The entire accident flight was recorded on the engine monitor. Prior to the loss of engine power, engine fuel flow and fuel pressure drop, immediately followed by engine RPM. Prior to the initiation of the forced landing, fuel flow drops from about 31 gallons per hour (gph) to 2-3 gph, fuel pressure drops from about 38 pounds per square inch (psi) to 5-6 psi, and engine RPM drops from about 2,700 to about 1,400. The last data points prior to the interruption of electrical power to the unit were 1 gph fuel flow, 3 psi fuel pressure, and 1,390 RPM. The number 4 cylinder EGT and CHT parameters appeared to drop off prior to takeoff; however, they recovered during the application of takeoff power and remain aligned with the other cylinders for the remainder of the flight.
A partial loss of engine power after takeoff for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation.
Source: NTSB Aviation Accident Database
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