Incident Summary
According to the pilot, the aircraft underwent an annual inspection on August 2, 2001. During the inspection, maintenance tasks included removal and replacement of the oil pump impellers, and the throttle linkage was disconnected to expedite the job. After the aircraft was returned to service, it accumulated nine-tenths of a flight hour and seven takeoffs. While in the landing pattern, the throttle did not respond to the pilot's input. The pilot executed a partial power go-around, and the aircraft subsequently crashed into trees at the end of the runway.
Wreckage Examination
Examination of the wreckage revealed that the throttle cable was disconnected at the carburetor. The drilled bolt, castellated nut, or locking cotter pin that typically secures the throttle cable-to-carburetor connection was not found.
Pilot Observations
The pilot reported that since the annual inspection, he detected a slight detent in the throttle motion at approximately 1,100 rpm engine speed. However, he did not mention this observation to the mechanic.
Maintenance Sign-Off
The FAA certified Inspection Authorization (IA) who signed off the work stated that he was 99.9 percent certain that the attaching hardware was correctly installed.