What happened
On October 18, 2009, a Cessna P210N Silver Eagle conversion aircraft, registration N7217S, impacted terrain during an emergency approach to Garfield County Regional Airport (RIL) in Rifle, Colorado. The flight was being conducted under Part 91 regulations in visual meteorological conditions with 10 miles of visibility.
Shortly after departing Runway 26, the pilot attempted to reduce power. The engine failed to respond to power lever adjustments until the lever reached the flight idle position, at which point power decreased immediately. When the pilot attempted to increase power, the engine did not respond until the lever reached the full forward position.
In preparation for an emergency landing, the pilot turned downwind and cycled the power between flight idle and full power multiple times to maintain airspeed. During the final approach, the pilot attempted to increase power, but the engine failed to respond. The aircraft landed approximately 300 feet east of the Runway 26 approach end and 100 feet south of the extended centerline, subsequently flipping onto its back. The pilot sustained one minor injury and the aircraft was substantially damaged.
The investigation
Investigators found that the power lever and condition lever control cables had separated from the coordinator unit in the engine compartment due to overload forces.
An examination of the Rolls-Royce 250-B17F2 turbine engine revealed no evidence of foreign object damage, compressor failure, or malfunctions in the accessory gearbox or turbine section. The Honeywell fuel control unit and the Woodward propeller and power turbine governors were all bench tested and found to be functioning normally.
During operational ground testing, investigators and an independent instructor were able to duplicate the power anomalies. They found that manipulating the propeller condition lever caused the engine power to drop to a level similar to flight idle and, in one instance, caused the engine to quit.