Accident Overview
On July 4, 2010, at approximately 2218 Pacific daylight time, a Cessna 210K (registration 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; no flight plan was filed. The local flight, conducted under 14 CFR Part 91, had departed a private airstrip near Newman, Washington, about 2130.
Pilot Report
According to a statement submitted to the Safety Board investigator-in-charge (IIC), the pilot measured fuel in both tanks with a ruler prior to departure. The left tank fuel level was 3 inches from the bottom; the right tank was 5 3/4 inches from the bottom (full being 7 3/4 inches). The pilot sampled both tanks and observed no water. After completing the preflight inspection, he boarded the three passengers. After takeoff and landing gear retraction, he climbed to 3,500 feet mean sea level, set power at 20 inches manifold pressure and 2,400 rpm, adjusted mixture, set exhaust gas temperature 100°F cooler than peak, and closed the cowl flaps. After circling approximately 8 to 10 times, the engine suddenly quit with no warning. The pilot switched tanks from right to left, pushed throttle and mixture full open/rich, activated the electric boost pump, but could not restart the engine. He initially turned toward a local airport but realized he could not reach it. He radioed another pilot that he would land on an interstate highway. At about 300 feet above ground level, he applied full flaps and attempted to land between traffic, flaring over two cars and landing in front of them with one car ahead. The left main landing gear did not fully extend, causing the airplane to veer left into a center guard rail, skid approximately 500 feet against it, then swing into the median and come to rest against the back side of the eastbound center guard rail.
Post-Accident Examination
A Federal Aviation Administration (FAA) aviation safety inspector reported several gallons of fuel observed in each tank at the site; about 25 gallons of fuel was recovered from the aircraft. The airplane was examined at the owner's private hangar under supervision of the IIC, with FAA and technical representatives from Cessna Aircraft Company and Teledyne Continental Motors (TCM) present. Airframe damage included the outboard section of the left wing, left flap, left main landing gear, left horizontal stabilizer, left elevator, empennage, bottom left engine cowling, and the nose landing gear had separated. The fuel system was unremarkable: all tanks, lines, screens, valves, caps, vents, and boost pump were clear, clean, and properly secured. The electric boost pump produced suction and pressure when powered. The propeller remained attached; two blades had leading edge tip damage—one consistent with striking the guard rail, the second bent 8 inches aft about 30°—and the third blade bent slightly aft with leading edge damage and transfer of guard rail material. No pre-impact airframe anomalies were noted.
Engine Examination
Engine examination via borescope revealed light gray deposits on cylinders, piston heads, and combustion chambers; valve heads were undamaged with no abnormal thermal discoloration. The crankshaft rotated by hand with cylinder compression and valve continuity obtained. Cylinder overhead components were lubricated. Throttle body linkage and fuel metering unit moved freely. Both magnetos rotated with impulse coupling engagement and spark visible from each ignition lead end. Spark plugs had worn-out normal wear signatures with light gray deposits. The fuel pump drive coupling was intact; the pump rotated freely and flowed fuel when driven by an electric drill. The fuel manifold valve contained fuel; its screen was clear. Fuel injection nozzles were unobstructed. No abnormalities were found that would have prevented normal operation or production of rated horsepower.
Probable Cause
None stated in the source.