CEN17LA239

After reaching 12,500 ft altitude, the private pilot attempted to adjust the boost control of the experimental amateur-built airplane's engine. When he did so, the engine experienced a total loss of power. The pilot subsequently performed a forced landing to a field. A postaccident examination of the engine revealed no anomalies. The examination revealed that the airplane was powered by an aircraft engine that was modified to employ a belt-driven automotive centrifugal supercharger. Due to the experimental nature of the supercharger installation, no determination could be made regarding its installation or operation; however, no outward signs of a failure or malfunction were observed. Based on the available evidence, the reason for the loss of engine power could not be determined.

On June 4, 2017, about 1609 central daylight time, an amateur-built Lancair Legacy 2000 airplane, N169BZ, sustained substantial damage during a forced landing following a loss of engine power during cruise flight near Georgetown, Texas. The pilot and passenger were not injured. The airplane received substantial damage to its wings and fuselage when the landing gear separated from the airplane. The airplane was registered to DA Leasing LLC and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which was not on a flight plan. The local flight originated from the Georgetown Municipal Airport (GTU), Georgetown, Texas, about 1540. The pilot reported that the flight was to evaluate airplane performance. Upon reaching an altitude of 12,500 feet above mean sea level (msl), the pilot adjusted the engine boost control and the engine lost all power. He returned the boost control to its previous position, but the engine did not resume power production. He reported that he was unable to restart the engine and attempted to glide back to GTU. Insufficient altitude resulted in the airplane landing about 1.5 miles southeast of GTU. A postaccident examination of the airplane was conducted by Federal Aviation Administration inspectors. The airplane was equipped with a Continental Motors IO-550-C engine. The engine was outfitted with an automotive belt driven centrifugal supercharger. The supercharger fed pressurized air to the engine's fuel injection throttle body and the manifold pressure (boost) was controlled by the pilot using a vernier control in the cockpit. Examination of the basic Continental engine found no anomalies. Due to the experimental nature of the supercharger installation, no determination could be made regarding its installation or operation; however, no outward signs of a failure or malfunction were observed.