Accident Description
On approach to landing, the flight instructor, who occupied the right pilot seat, observed a loss of engine power. After landing and during the rollout, the engine quit. Subsequently, the student pilot in the left seat observed flames coming from his side of the engine cowling. The instructor pilot then noticed smoke and flames emanating from his side of the cowling, prompting both the instructor and the student to evacuate the airplane.
Examination Findings
An examination of the airplane revealed thermal damage to the firewall and all four engine mounts. Two days after the accident, an FAA inspector observed the operation of the electric fuel pump to be "normal." However, while observing the electric fuel pump, the inspector also noted the carburetor leaking a steady stream of fluid. A subsequent examination of the airplane's carburetor revealed that prior to flow testing, the unit did flood before being tapped, after which it held fuel pressure. An examination and teardown of the carburetor determined that the carburetor float was restricted due to a misadjusted retractor clip, which allowed fuel to pass the needle valve before being expelled from the carburetor. This fuel was then ignited by an undetermined source.
Additional Inspection
Further investigation revealed that two days prior to the accident flight, an incorrect electric fuel pump had been installed on the airplane during a 100-hour inspection. The pump bore the designation "FOR EXPERIMENTAL USE ONLY."
Conclusion
The accident sequence involved a loss of engine power during approach, followed by engine stoppage and a post-landing fire. The fire was fueled by a carburetor leak resulting from a restricted float due to a misadjusted retractor clip, with ignition from an undetermined source.