History of Flight
On March 30, 2010, about 1830 eastern daylight time, a Cessna 182P, registration N52790, operated by the Montgomery County Department of Transportation, experienced a loss of engine power during a flight from Montgomery County Airpark (GAI) in Gaithersburg, Maryland. The pilot and sole passenger, a county employee, were conducting a traffic observation flight. The pilot reported challenging winds but considered them within safety margins. The flight departed GAI about 1620.
During the flight, the pilot noted increasing surface winds and turbulence, leading her to return earlier than planned. She aborted the first approach to GAI due to turbulence and windshear. After monitoring weather at Ronald Reagan Washington National Airport (DCA) and being given surface wind information for Frederick Municipal Airport (FDK), she elected to proceed to FDK. While approximately 5 nautical miles south of FDK, the aircraft encountered severe turbulence, causing a rapid climb followed by an immediate violent descent. At that moment, the engine abruptly lost power and did not respond to throttle inputs. Restart attempts failed. The pilot selected a forced landing site at Monocacy National Battlefield, touching down on wet grass. The airplane bounced, then during rollout with brakes applied, it collided with a culvert and nosed over. Both occupants exited with minor injuries.
Aircraft Information
The 1974 Cessna 182P (serial number 18262846) was powered by a 230-horsepower Teledyne Continental Motors O-470-U37(B) engine with a fixed-pitch propeller. The engine had been rebuilt and installed in 2005, accumulating 1,258 hours since then. The last magneto timing check was in January 2010, 129 flight hours before the accident. There was no record of inspection of magneto primary contact points since engine installation.
Meteorological Information
At 1615 (5 minutes before departure), the departure airport reported wind from 320 degrees at 13 knots with gusts to 24 knots. At 1823 (7 minutes before the accident), Frederick Municipal Airport reported wind from 340 degrees at 11 knots with gusts to 21 knots, visibility 10 miles, scattered clouds at 3,900 feet, broken at 6,000 feet, overcast at 6,500 feet, temperature 13°C, dew point -6°C, altimeter 29.68 inches Hg.
Wreckage and Impact Information
Post-accident examination revealed flight control continuity. The fuel selector was in the "both" position; left tank contained about 12 gallons, right about 8 gallons. No fuel was in the fuel strainer, but supply lines were clear. The mixture control lever at the carburetor was in idle cutoff, while the cockpit control was full rich; the vernier cable had pulled out of its clamp. Engine continuity and compression were confirmed. The carburetor bowl contained about 3/8 inch of fuel with no float binding. Spark plugs were normal except oil-soaked due to inversion. Ignition harness tested satisfactory. Magnetos were timed at approximately 22° BTDC (specification 24° BTDC). No spark was observed during rotation with leads connected. Examination of the left magneto found very weak spark and a primary contact point gap of about 0.002 inch (specification 0.008-0.012 inch). After adjusting the gap to 0.010 inch, no spark was produced; new contact points restored spark. The right magneto also had a point gap of about 0.002 inch; after adjustment to 0.010 inch, spark was observed. No pre-impact defects were found in the P-leads or ignition switch.