What happened
A commercial certificated pilot was performing a landing at a remote gravel airstrip. During the final approach to the gravel bar, the aircraft encountered a minor downdraft. As the pilot attempted to increase engine power to arrest the descent, the engine failed to respond to throttle inputs. Despite pumping the throttle, there was no increase in power. The aircraft continued its descent and touched down in an area of low brush approximately 50 yards short of the airstrip. Upon touchdown, the right main landing gear collapsed and the right wingtip struck the ground. The pilot was not injured.
The investigation
The pilot, who also holds an aircraft mechanic certificate, noted that the engine had been overhauled and reinstalled on the aircraft three days prior to the accident, which included the installation of an overhauled carburetor. Following the accident, the pilot observed that while the engine would start and run at idle power, there was binding in the carburetor's throttle cable or internal linkage. After replacing the throttle cable, the binding persisted. The pilot determined that when the throttle cable was disconnected and the throttle arm was operated by hand, the binding only occurred while the engine was running. An investigation of the carburetor conducted by the NTSB Interstate Investigator Coordinator at an aviation maintenance facility revealed no mechanical malfunctions.