On March 11, 2023, about 1130 mountain daylight time, an experimental amateur-built Zenith CH 801, N638BH, was substantially damaged when it was involved in an accident near Brigham City, Utah. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he departed Brigham City Regional Airport (BMC) and while ascending, about 200 to 300 ft above ground level, the airplane sustained a loss of thrust, but the engine continued to run. Unable to maintain altitude, the pilot elected to land on the remaining runway. Subsequently, the airplane landed hard, and the nose landing gear collapsed. The pilot stated that he defueled about 40 gallons of fuel from the airplane after the accident.
A pilot-rated passenger in the airplane reported that, during the first lap in the pattern, while on the downwind leg, the engine rpm seemed to fluctuate, as if the engine was surging. Not having been in this type of airplane before, he did not know if the fluctuating rpm was normal. While on final approach to land, the pilot moved the propeller control full forward, landed the airplane, and started to take off again. However, during the initial takeoff climb, the pilot stated he had no power. The passenger looked at the engine rpm and it seemed normal. The pilot then said, ‘we got the power back’. The passenger noticed they had plenty of runway and recommended the pilot land the airplane. During the landing flare, the airplane landed hard.
Postaccident examination of the airplane identified structural bending of the aft fuselage. Flight control continuity was established from all primary flight control surfaces to the cockpit controls.
Examination of the recovered airframe and engine revealed no preaccident mechanical failures or malfunctions that would have precluded normal operation. A visual inspection was conducted of the fuel system. Continuity was established from the main fuel tanks throughout the system to the carburetor. The airframe fuel strainer was void of fuel.
An external fuel source was mounted to the right-wing fuel inlet line to facilitate a test run. The engine started during the initial attempt and ran through various power settings uneventfully for about 5 minutes. Due to the damaged propeller, the throttle was not advanced to the full power position. However, the engine did produce a static rpm of 2,600.
The propeller governor was removed for further examination. There were no visible signs of damage and the governor control lever moved freely from stop to stop. The propeller governor was functionally tested and performed within the manufacturer's specifications.