NTSB Factual Report

On July 4, 2010, about 2218 Pacific daylight time, a Cessna 210K, N8133G, sustained substantial damage following a loss of engine power and subsequent forced landing on an interstate highway near Coeur d'Alene, Idaho. The private pilot and three passengers were not injured. Visual meteorological conditions prevailed at the time of the accident, and a flight plan was not filed. The local flight, which was being operated in accordance with 14 Code of Federal Regulations Part 91, had departed a private airstrip near Newman, Washington, about 2130.

In a statement submitted to the Safety Board investigator-in-charge (IIC), the pilot reported that prior to taking off to watch the July 4th fireworks display, he measured the fuel in both tanks with a ruler. The fuel in the left tank was 3 inches from the bottom of the tank and the fuel in the right tank 5 3/4 inches from the bottom, with 7 3/4 inches being full to the top of the tank. The pilot further reported than he then took samples from both tanks and observed no water. The pilot stated that he then performed the remainder of his preflight inspection before he boarded the 3 passengers. The pilot added that after taking off and retracting the landing gear, he climbed to 3,500 feet mean sea level, leveled off and set the throttle at 20 inches of manifold power and [the propeller] rpm at 2,400, adjusted the mixture, set the exhaust gas temperature 100 degrees cooler than peak and closed the cowl flaps. The pilot revealed that after circling around the area about 8 or 10 times, the engine suddenly quit.

The pilot stated that prior to the engine failure he had been monitoring the instruments and did not notice anything abnormal. "There was no warning when the engine quit producing power." The pilot reported that he immediately switched tanks from the right to the left, pushed the throttle and mixture full open and full rich and activated the electric boost pump, but was unable to restart the engine. The pilot added that he initially turned toward a local airport, but soon realized that he couldn't make the airstrip. The pilot then radioed another pilot in the area that he would be [landing] on an interstate highway in the westbound lanes. The pilot stated, "At approximately 300 feet above ground level (agl) I applied full flaps and tried for an opening in the traffic. It worked out about right and I flared over the top of two cars, landing just in front of them and with one car in front of us." The pilot further stated that the left main landing gear did not fully extend, which caused the airplane to veer left against the center guard rail before skidding approximately 500 feet and staying against the guard rail. After the airplane reached the end of the guard rail it swung into the median, where it came to rest against the back side of the east bound center guard rail.

A Federal Aviation Administration (FAA) aviation safety inspector reported that several gallons of fuel was observed in each tank at the site of the accident. The inspector further reported that about 25 gallons of fuel was recovered from the aircraft.

Following recovery and under the supervision of the IIC, the airplane was examined at the airplane owner's private hangar. Present during the examination was the FAA and technical representatives from both Cessna Aircraft Company and Teledyne Continental Motors (TCM).

An examination of the airframe revealed damage to the outboard section of the left wing, the left flap, the left main landing gear, the left horizontal stabilizer and the left elevator. The empennage and bottom left engine cowling area were also damaged. The nose landing gear was observed separated from the airplane.

The examination further revealed that the aircraft's fuel system was unremarkable. All tanks, lines, screens, valves, caps, vents, and boost pump were clear, clean, and properly secured. The electric boost pump was removed and produced suction and pressure when powered by the aircraft battery.

The propeller remained attached to the crankshaft propeller flange. Two of the propeller blades displayed leading edge tip damage. One displayed an impact signature consistent with striking the guard rail, and 8 inches of the tip of the second blade was bent aft approximately 30 degrees. The third propeller blade was bent slightly aft, displayed leading edge damage at the tip and a spanwise scrap and transfer of material from the guard rail. All blades remained secured in the propeller hub.

No pre-impact anomalies were noted to the airframe.

An examination of the airplane's engine revealed that when boroscoped the cylinders, piston heads and combustion chambers had light gray deposits, and the valve heads were undamaged and exhibited no signs of damage or abnormal thermal discoloration. The crankshaft was rotated by hand and cylinder compression and valve continuity was obtained. The cylinder overhead components were lubricated and undamaged. The throttle body linkage and valve and the fuel metering unit and linkage were undamaged and moved freely during cabin control continuity. Both magnetos remained attached to the engine. The crankshaft was rotated and the magnetos rotated with impulse coupling engagement and spark was visible from each ignition lead end. The ignition leads were undamaged. In accordance with the Champion AV-27 chart, the spark plugs had (Worn Out - Normal) wear signatures, which indicated a normal service life. The spark plug electrode areas had light gray deposits. The fuel pump was removed from the engine and the drive coupling was found intact. The fuel pump drive shaft rotated freely by hand. The fuel pump was dipped in a bucket of fuel and was driven by an electric drill. Fuel flowed freely from the fuel pump.

The fuel manifold valve was removed from the engine and disassembled. Fuel was found in the manifold valve cavity and the screen was clear of debris

The fuel injection nozzles were undamaged, removed from the engine and visually observed to be unobstructed.

The inspection of the engine did not reveal any abnormalities that would have prevented normal operation and production of rated horsepower.

NTSB Probable Cause

The loss of engine power during cruise flight for undetermined reasons.