On May 10, 1992, a Cessna 177 (registration N177RD) operated by Dennis Construction Inc. was involved in an aviation accident near Lusby, MD. Investigators recorded the probable cause as: A FAILURE OF THE CARBURETOR RESULTING IN A LOSS OF ENGINE POWER. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During initial climb, an engine backfire and partial power loss resulted in the aircraft crashing into wooded terrain approximately 250 feet beyond the runway end. Examination of the carburetor revealed a missing primary venturi with melted and resolidified legs.
Accident Details
During the initial climb following takeoff, the aircraft's engine backfired and experienced a partial loss of power. Subsequently, the airplane crashed into wooded terrain located about 250 feet beyond the end of the runway. The crash site was in a wooded area adjacent to the departure end of the runway.
Examination of Carburetor
The carburetor was disassembled for inspection. All components were accounted for except the primary venturi. The primary venturi is retained by three legs. Two of these legs were found separated from the throttle body, and the third leg was completely missing. Visual examination of the remaining portions of the two separated legs revealed a melted and resolidified appearance, indicating exposure to high temperatures.
Analysis of Components
One of the leg pieces was removed from the throttle body and subjected to ultrasonic cleaning in acetone. It was then analyzed using X-ray energy dispersive spectroscopy (EDS) in areas that exhibited a fresh metal appearance. The EDS analysis generated spectra showing large zinc peaks and a much smaller peak for aluminum.
