Accident Summary
On November 19, 2015, at approximately 1400 Pacific standard time, a Cessna P210N, registration N9824G, experienced a partial loss of engine power shortly after takeoff from Harris Ranch Airport (3O8) near Coalinga, California. The aircraft was operated by the private pilot under 14 CFR Part 91 for a personal cross-country flight destined for Shafter-Minter Field (MIT) in Shafter, California. Visual meteorological conditions prevailed, and no flight plan was filed. The pilot and two passengers were not injured. The aircraft sustained substantial damage to its undercarriage and left wing during the forced landing.
Pilot Report
The pilot stated that during the takeoff roll, he advanced the power to 70 psi torque and rotated at 70 knots. After rotation, he lowered the nose to maintain the target climb speed. When the aircraft reached an altitude of about 200 to 300 feet above ground level, the engine experienced a partial loss of power. The pilot noted no abnormal fuel system indications. He advanced the throttle and condition levers, but the power available was insufficient to climb or maintain altitude. During the subsequent forced landing, the airplane struck multiple power lines before executing a gear-up landing in an open dirt field. The aircraft came to rest upright.
Engine Examination
On January 7, 2016, under the supervision of the NTSB investigator-in-charge and FAA inspectors, a Rolls-Royce field technician examined the engine, a Rolls-Royce model 250-B17F/2. The compressor intake had crushing damage to the front support, but the compressor could still be rotated by hand. Rotational continuity from the compressor to the gas-generator turbine and starter/generator was verified, and no rotational damage to the compressor blades was found. Soil was present around the front of the engine and compressor intake, but there was no evidence of foreign object ingestion. The compressor bleed valve operated manually with ease. N2 drive continuity from the power turbine to the sun gearshaft was smooth and quiet. Visual examination of the 4th stage power turbine and gas-generator turbine showed no damage or abnormal combustion.
Compressed air was applied to the engine control pneumatic system. A minor air leak was noted at the Pc air filter, and a larger leak was found at the propeller overspeed governor Py air inlet B-nut, producing about one 1-inch bubble every ten seconds. According to the technician, this leak was not significant enough to affect engine performance. A similar leak was found on the impact-damaged Py line connecting the propeller overspeed governor to the propeller/power turbine governor.
Fuel was present in the fuel spray nozzle supply line, fuel pump filter bowl, and fuel supply line fitting at the firewall. The fuel spray nozzle's internal filter screen was free of debris. Compressed air applied to the aircraft's fuel system resulted in a flow of clean fuel. The airframe oil tank contained ample clean oil, and the #1 magnetic chip detector was free of ferrous debris. The technician concluded that there was no evidence of a mechanical engine failure.
Component Testing
On February 18, 2016, under FAA supervision, the airplane's propeller governor and overspeed governor were examined and functionally bench tested by a Woodward Inc. technician. The propeller governor showed no anomalies that could have caused the reported loss of power. The overspeed governor's test revealed that the pressure for the set point of the overspeed limiter was 3.0 psid, approximately 0.2 psid below the minimum range of manufacturer specifications. However, Woodward stated that none of the shifts in data supported a conclusion that the overspeed governor could cause a loss of power.
Investigation Conclusion
The investigation failed to determine what precipitated the reported loss of engine power.