Accident Summary
On December 23, 2016, at 1013 mountain standard time, a Kitfox 7, registration N320RJ, lost engine power while on a visual approach from the airport traffic pattern at Yellowstone Regional Airport (COD) in Cody, Wyoming. The pilot executed a forced landing in a field, where the airplane nosed over and sustained substantial damage. The commercial pilot, who was the sole occupant, was not injured. The flight was conducted under 14 CFR Part 91 as a pilot proficiency flight, originating from COD around 1000, and was intended to remain in the traffic pattern. Visual meteorological conditions prevailed, and no flight plan was filed.
Background
The pilot was employed as a flight instructor at Choice Aviation at COD. The accident airplane was owned by a former student who had obtained a private pilot certificate in November 2016, having received all training from the pilot using a Cessna 172M. The owner planned to fly the Kitfox and had asked the pilot to gain proficiency in it to provide future instruction. A condition inspection was performed on October 20, 2016, by Choice Aviation.
A checkout flight on November 5, 2016, ended shortly after takeoff due to engine roughness. Maintenance then installed check valves in the fuel system and replaced the fuel pressure regulator. A second checkout flight on December 22, 2016, with the chief pilot revealed slight engine roughness at high power settings, which was less severe than before; the engine ran normally at 35 inches of manifold pressure and below. After that flight, a mechanic adjusted the fuel pressure to the maximum setting to address the high-power issue.
Sequence of Events
On the accident day, the pilot performed a thorough preflight and started the engine using the choke in cold weather. While holding short of runway 22, he ran the engine to 4,000 rpm, checked ignition, then turned on fuel pump "B" and ran to maximum power, observing 23 psi fuel pressure with smooth operation. When he reduced power to 4,000 rpm and turned off both pumps, the engine slowly quit, but he restarted and taxied to maintenance. With the mechanic, a run-up showed normal operation with both fuel pumps on; with pumps off, fuel pressure dropped but the engine did not quit. The mechanic exited, and the pilot taxied to the runway for another run-up at 4,000 rpm with both pumps on, which was normal.
During takeoff from runway 22, the pitot tube rotated sideways, causing an airspeed indication of 0 knots. The pilot flew a left traffic pattern. On left downwind abeam the runway numbers, he reduced power to 15 inches of manifold pressure with both fuel pumps on. Sensing an issue, he applied power but got no response. He turned onto left base, maintained best glide attitude, and attempted throttle adjustments without result. He performed a forced landing in a grass field short of runway 22 due to a snow bank. The airplane rolled about 75 feet before the nose landing gear collapsed, then slid about 90 feet.
Post-Accident Examination
Examination revealed that a black fuel line to the pressure regulator was ¼ inch in diameter. The absolute pressure sensor was not mounted with a screw through its hole; instead, it was attached to the engine frame with a black sealant. The fuel selector was in the off position, but all shut-off valves were on. Fuel consistent with 100LL aviation fuel was present in both tanks. The pitot tube was rotated inward. Engine control continuity was confirmed. The pressure regulator had a gouge on its adjustment screw retaining nut. The Hobbs meter read 109.7 hours.
The oil level was checked by rotating the propeller; the quantity exceeded the maximum capacity by about 16 ounces. This excess was drained before engine runs. The propeller was replaced due to accident damage.
Engine System Testing
During a post-accident engine run, the engine started after six attempts and ran for about 5.5 minutes at full power without issue. A second run replicated the accident: after running at full power with both fuel pumps on, reducing to 15 inches of manifold pressure caused the engine to quit and it could not be restarted. Examination of fuel lines showed fuel present and pressure in the line to the pressure regulator when pumps were on. The return line contained fuel. The engine was unable to restart after several attempts.
Subsequently, the interior was removed to inspect the fuel system; no leaks or obstructions were found. A transparent-green return line from the pressure regulator connected to the bottom left of the fuel header tank behind the passenger seat. Another transparent-green line from the top of the header tank had a transducer spliced in, connecting to the right fuel tank. Fuel was present up to the transducer but not above it. Black fuel lines from both wing tanks connected to the bottom of the header tank.
For further testing, the pressure regulator return line was disconnected and a hose inserted into the right-wing filler port. A dual needle gauge was attached. After several start attempts, the engine started with fuel pressure at 62.5 inches and manifold pressure at 29 inches. When power was reduced to about 17 inches with pumps on, the engine quit. The pressure regulator screw was turned one turn to decrease fuel pressure. Thereafter, the engine started more easily and ran without loss of power at full power and 15 inches both with and without the fuel pump. Cycling the throttle between full power and 15 inches with pumps on showed no loss of power.