Accident Summary
During the flight, the pilot attempted to make a throttle adjustment but found it had no effect on the engine RPM. After entering the downwind leg abeam his intended touchdown point, the pilot shut down the engine and attempted to glide the remaining distance. The aircraft touched down short of the runway and subsequently struck an embankment.
Inspection Findings
A post-accident inspection of the aircraft revealed that the throttle linkage had separated from the carburetor throttle arm. The bolt, castellated nut, and washer that secure the assembly together were not present.
Maintenance History
The engine had been reinstalled in the aircraft following a major overhaul, which occurred 1 month and 2 operating hours prior to the accident. An annual inspection was also completed and signed off at that time.
Mechanic Statements
The mechanic who performed the engine reinstallation stated that the bolt had been reinstalled and that a cotter pin had also been installed in the process. The mechanic who performed the annual inspection reported that he had not looked that closely at the engine since it had just been installed and inspected by another mechanic.
Manufacturer's Assessment
The manufacturer reported that the design of the assembly does not place loads on the bolt that would be sufficient to produce an overload failure.