Incident Overview
A commercial pilot with 6,127 hours of flight experience encountered a throttle lock while leveling off during an enroute descent. The pilot attempted to add power but found the throttle would not advance. Subsequent efforts to wiggle the throttle back and forth were unsuccessful, with the throttle remaining stuck at approximately 1,000 RPM.
Forced Landing and Nose-Over
As the airplane continued to descend, the pilot executed a forced landing. Just prior to touchdown, the pilot pushed the throttle forward with significant force, feeling it pop loose. Afterward, the throttle could be moved aft and forward but had no effect on engine RPM. The airplane landed on rough and uneven terrain and nosed over during the ground roll.
Maintenance History and Investigation
A review of the airframe logbooks revealed that the aircraft had been previously repaired after earlier mishaps. The entire airframe was rebuilt in July 2003, which included replacement of the firewall during a scheduled overhaul. Additionally, a newly overhauled engine had been installed approximately 3.5 hours before the incident.
The investigation determined that a throttle cable support angle was missing from the firewall. No evidence was found to confirm that the support angle was present when the engine firewall was last replaced.