What happened
While en route, the pilot decided to divert to Hesperia because of weather conditions. During the descent, the pilot discovered that the throttle control was frozen and could not be moved when an attempt was made to add power. The throttle remained stuck at an engine power level that was insufficient to maintain level flight. While attempting to maneuver the aircraft toward the runway, it collided with high tension power lines.
The investigation
FAA airworthiness inspectors examined the aircraft and confirmed that the throttle was frozen in an intermediate setting. Records indicated that the engine had been overhauled on June 18, 1991, a process that included an overhaul of the carburetor, new throttle bushings, and a new shaft.
Maintenance logs from Southbay Aviation revealed that between the engine overhaul and the accident, there were six prior complaints from renter pilots regarding the throttle sticking on an intermittent basis. The recorded corrective action for these previous discrepancies was the replacement of the throttle cable.