WPR19LA023

During takeoff on the first flight since the airplane was built, the engine began to lose power. The passenger conducted a series of troubleshooting steps while the pilot flew the airplane. Unable to restore engine power, the pilot landed in a rock-covered field. The airplane came to rest upright; a postimpact fire ensued and consumed most of the airplane. Postaccident examination of the engine revealed no evidence of any preexisting mechanical malfunctions that would have precluded normal operation. The airplane was equipped with an electric constant speed propeller, which was controlled by an electric propeller controller. Due to the postimpact fire damage sustained to the airplane, functional testing of the propeller control unit could not be performed. Due to the lack of available information, the reason for the partial loss of engine power could not be determined.

On November 10, 2018, about 0752 Pacific standard time, an experimental amateur-built Vans RV-7A airplane, N5433T, was destroyed when it was involved in an accident in Ramona, California. The private pilot (flying pilot) and pilot-rated passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The passenger reported that they had just completed the build of the airplane, and that the pilot flying was going to conduct the initial flight due to the amount of flight time he had accumulated in the make and model of the airplane. They performed an engine runup at the hold-short line for runway 27 and noted nothing abnormal. The passenger stated that the flying pilot advanced the throttle for takeoff, and the engine had plenty of power during the takeoff roll. During climb out, about 500 ft above the ground, the engine began to gradually lose power. The passenger started to troubleshoot the loss of power; he verified the fuel pumps and ignition were on, the fullest fuel tank was selected, fuel pressure and air/fuel ratio gauges indicated “in the green,” the propeller rpm was 2,700, and the propeller was in auto mode. As the passenger conducted a second check, he motioned for the pilot to take the propeller controller out of auto and put it in manual mode. During the landing roll, the right main landing gear separated after it struck a rock. As the airplane came to rest upright, a postimpact fire ensued, which consumed the inboard sections of both wings and the fuselage. The airplane was recovered to a secure location for further examination. The airplane was equipped with a 6-cylinder Subaru engine and gear reduction unit, which powered an electric, constant-speed MT propeller through an electric propeller control unit. The postaccident engine and gearbox examination was performed by one of the co-builders of the airplane under the supervision of a Federal Aviation Administration inspector. The engine exhibited varying degrees of thermal damage. No scoring on the cylinder walls or piston damage was observed. The oil filler cap was destroyed by fire, and the internal positions of the engine and cylinders exhibited corrosion. The reduction gearbox rotated freely and exhibited evidence of a lubricant leak at the rear input shaft seal. The gearbox was disassembled, and no evidence of any internal failure was observed. The electric propeller control unit was destroyed by fire, which precluded functional testing of the unit.