Accident Overview
On July 16, 2022, at about 0635 central daylight time, an experimental amateur-built Thatcher CX4, registration N347CX, was substantially damaged in an accident near Baker, Florida. The pilot sustained serious injuries. The airplane was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Pilot Report
The pilot reported that he had recently completed an overhaul of the automotive conversion engine. Earlier that month, he conducted several engine ground runs, during which the engine would not run smoothly at idle throttle setting. However, on the last ground run, the engine ran smoothly at idle power with left, right, and both ignition sources. On the accident day, the pilot planned to break in the engine during a flight over the airport. The engine started normally, although it "hit a rough spot at one point on taxi and low RPM." He determined that the engine was not fully warmed up and continued. After takeoff, while climbing to traffic pattern altitude, the pilot felt something dripping onto his leg. Thinking it was fuel, he decided to perform a precautionary landing rather than continue the climb. When he reduced throttle to idle to initiate a descent, the engine stopped producing power. Unable to restore power, he navigated toward the airport, but the airplane could not reach the runway. He selected a field short of the airport for a forced landing. During the landing, the left wing contacted a tree, resulting in the right wing and nose impacting the ground.
Wreckage Examination
Examination by a Federal Aviation Administration inspector revealed that the main wreckage came to rest in a nose-down attitude at the edge of a road. Both wings and the fuselage sustained substantial damage.
Postaccident Findings
The pilot later determined that it was likely condensation, not fuel, that dripped on his leg after departure. Although he did not run the engine due to propeller damage, his postaccident examination found no anomaly that would have precluded normal operation. He reported that the loss of engine power could have been due to the idle setting or carburetor icing. At the time of the accident, the temperature and dew point at a weather reporting facility 9 nautical miles southeast of the site were both 73.4°F, with 100% relative humidity, conditions conducive to carburetor icing at glide power.