WPR14LA185

A complete loss of engine power for reasons that could not be determined because of insufficient evidence.

The private pilot had recently purchased the experimental airplane, and the flight was the second leg of his cross-country trip to fly the airplane home from the purchase location. After the first leg, the pilot topped off the main and auxiliary (wing) fuel tanks, which, according to the pilot's operating handbook (POH) for the airplane, provided a total usable fuel quantity of 53 gallons. After flying about 3.5 hours, when the airplane was about 20 miles short of the planned destination, the engine lost total power, and the pilot was unable to restart it. During a forced landing in a field, the airplane nosed over and came to rest inverted. When the airplane was righted during recovery, about 4 to 5 gallons of fluid drained from the area where the main fuel tank and the smoke oil tank were mounted; however, it was not determined whether the fluid was fuel or a mixture of fuel and smoke oil. The auxiliary tank was breached, and no determination of its postimpact fuel quantity could be made. The engine was a highly modified aftermarket version of one of two different models produced by the original engine manufacturer, a 360-horsepower (hp) model and a 400-hp model, and no specific fuel burn chart for the modified engine had been developed. The pilot's flight planning, which was based on fuel burn rates for a 360-hp engine, indicated that the flight would consume about 45 gallons of fuel. Calculations using the POH fuel burn rates, which were for a 400-hp engine, indicated that the flight would consume between 51 and 58 gallons, depending on the power setting. Because the auxiliary fuel tank was not equipped with any quantity indication system, and the main tank fuel quantity indicator was difficult for the pilot to see, the pilot used an engine information system (EIS) to determine the fuel state of the airplane. The EIS used a pilot-entered initial fuel quantity and a sensed fuel flow rate to calculate the fuel remaining. Although the pilot reported that the EIS indicated that about 11 gallons of fuel was on board at the time of the power loss, the investigation was unable to determine the accuracy of that EIS-calculated quantity. Based on the available information, the power loss was likely the result of either an ignition or fuel problem. However, due to damage to the airplane that precluded a complete examination of the ignition and fuel systems, a lack of design and construction information, and the inability to accurately determine the airplane's postimpact fuel quantity, the reason for the loss of engine power could not be determined.

***This report was modified on January 26, 2016. Please see the docket for this accident to view the original report.*** HISTORY OF FLIGHT On May 3, 2014, about 1945 mountain daylight time, an experimental amateur-built Pitts 12, N177MF, was substantially damaged in an off-airport landing near Bluffdale, Utah. The pilot/owner and his passenger received minor injuries. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no Federal Aviation Administration (FAA) flight plan was filed for the flight. According to the pilot, he had recently purchased the airplane, and he and his wife planned to fly it from the purchase location in Washington state to their home airport in New Mexico. The first flight of the day initiated from Arlington Municipal airport (AWO), Arlington Washington, and terminated in a planned stop at Columbia Gorge Regional Airport (DLS), The Dalles, Oregon. That flight leg was uneventful, and the pilot reported that he topped off the fuel tanks at DLS. The airplane departed DLS, with the pilot's next planned fuel stop in the vicinity of Provo, Utah. The pilot reported that he conducted the cruise portion of that flight at an altitude of 9,500 feet above mean sea level (msl). When the airplane was about 30 miles from Provo Municipal airport (PVU), Provo, the pilot began a gradual descent, and shortly thereafter, the engine quit. The pilot switched from the main tank to the auxiliary tank and attempted to restart the engine, without success. The pilot then turned his attention to selecting an off-airport landing site in an open field, and turned off all electrical equipment in the airplane. The airplane landed hard, and "flipped over on its back." The pilot exited, assisted his wife with her exit, and both walked away from the airplane because they smelled fuel. A passer-by arrived within about 15 minutes, and the local authorities were notified of the accident. An FAA inspector visited the accident site within an hour of the accident, but did not note any obvious deficiencies that he could associate with the loss of power. The airplane was recovered to a secure location 2 days after the accident. PERSONNEL INFORMATION The 53-year-old pilot held a private pilot certificate with airplane single-engine, multiengine land, rotorcraft-helicopter and instrument airplane ratings. According to the pilot, he had approximately 3,868 total hours of flight experience, including about 8 hours in the accident airplane make and model. His most recent FAA third-class medical certificate was issued in February 2013, and his most recent flight review was completed in May 2013. According to the pilot, he purchased the airplane in April 2014. Prior to his experience with the purchase of the accident airplane, the pilot had never flown a Pitts Model 12. His overall experience in the accident airplane make and model consisted of a 3-hour checkout with another individual the day prior to the accident, and then one flight leg (before the accident leg) on the day of the accident. AIRCRAFT INFORMATION The airplane was a tandem cockpit biplane. The designated pilot's cockpit was the rear cockpit, and the pilot occupied that cockpit for the flight. The airplane was manufactured in 2009 and was registered in the Experimental – Exhibition & Air Racing category. According to information provided by the pilot, the airplane had a total time in service of 146 hours, and its most recent annual inspection was completed in June 2013. The engine had a total time in service of 596 hours, and had accumulated 146 hours since its most recent overhaul. Review of the maintenance records did not reveal any unusual conditions or maintenance actions. The airplane was equipped with a Romanian Vendenyev M14 series radial engine. M14 engines were produced by the manufacturer in two series, both of which were carbureted: the 360 hp M14P and the supercharged 400 hp M14PF. An American engine facility, Barrett Precision Engines (BPE), developed several modifications for the M14 engines, including different pistons, different ignition systems, and fuel injection. BPE did not change the engine designations (M14P or M14PF) and did not independently develop or provide power or fuel flow charts for the engines it modified, in part because there were multiple permutations of BPE engine modifications. Just before its installation in the airplane, the M14P engine was overhauled by BPE, at which time several significant modifications, including high-compression pistons and a fuel injection system, were incorporated. According to a representative of BPE, "the engine was not tested at our facility as we did not have a test cell for the M14 at that time," and the installation, testing and "fuel flow set up" of the engine would have to have been accomplished by another facility. Investigative efforts to determine whether, when, or by whom the testing and fuel flow set up were accomplished were unsuccessful. METEOROLOGICAL INFORMATION The 1955 automated weather observation at PVU, located about 20 miles south southeast of the accident site, included winds from 190 degrees at 14 knots, visibility 15 miles, a broken cloud layer at 14,000 feet, temperature 23 degrees C, dew point 2 degrees C, and an altimeter setting of 29.84 inches of mercury. WRECKAGE AND IMPACT INFORMATION The airplane came to rest inverted in a field. The FAA inspector who responded to the scene the night of the accident was only able to make a cursory examination of the airplane. Due in part to the darkness and the airplane attitude, the inspector did not note any obvious pre-impact deficiencies or conditions that would have resulted in the power loss. Personnel from the recovery company noted that when they righted the airplane, about "4 to 5 gallons of av gas came pouring out of the bottom [main] fuel tank." They did not report exactly where the fuel exited from. The recovery personnel did not determine whether there was any fuel in the wing tank. The airplane was equipped with a smoke oil tank mounted near the main fuel tank. Neither the pre departure nor post accident oil quantity of that tank was determined, and the possibility that the smoke oil comprised a portion of the observed spill could not be discounted. As a result of those events and circumstances, the actual remaining fuel quantity at the time of the accident was not able to be determined. The investigation was unable to obtain detailed design and construction information such as system schematics and component manuals. The airplane was examined in detail at the recovery facility several months after the accident. The upper wing had been removed as a unit for recovery and transport, while the lower wings were cut and fracture-separated from the fuselage. The cockpits were intact. The engine was displaced aft and canted nose-down, but remained attached to all the engine mounts. The three blade wood/composite propeller damage was consistent with little or no power being provided to the propeller at the time of impact. All components of the airplane and engine were accounted for at the recovery facility. The engine was fuel injected, with a dual magneto ignition system controlled by two dedicated cockpit switches. Aside from crush damage to the underside, there was no obvious damage to the engine. The throttle/injector body was fractured and fracture-separated from the engine, and the throttle body placard identified it as an Airflow Performance brand "Experimental Fuel Control." Two fuel lines and the throttle linkage retained the throttle body to the engine/airframe. Throttle linkage continuity from the cockpits to the throttle body was confirmed, and the cockpit throttle controls moved synchronously through their full ranges. All spark plugs were installed and intact, with one exception due t