Incident Overview
An instructor was providing qualification training to the new owner of the airplane. During the fifth stop-and-go landing, the pilot reduced the throttle to idle while abeam the intended landing point. While on the base leg, the pilot advanced the throttle to adjust the rate of descent, but the engine did not respond and continued to run at idle speed. Control of the airplane was then transferred to the instructor, who also attempted to increase power without success.
Forced Landing and Impact
The instructor executed a forced landing to a cultivated field. Upon impact with the furrows, the left main landing gear was severed from the airplane.
Investigation Findings
Examination of the wreckage revealed the cause of the throttle failure: a retaining clip that anchored the throttle cable assembly to the firewall was missing. The absence of this clip allowed the entire housing of the cable assembly to move whenever the throttle was advanced or retarded, preventing the engine from responding to throttle inputs beyond idle.