NTSB Factual Report

On March 3, 2012, about 1440 eastern standard time, a Mooney M20M, N486KC, operated by a private individual, was substantially damage during a forced landing to a field, following a total loss of engine power near Amisville, Virginia. The certificated private pilot and passenger were seriously injured. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and an instrument flight rules flight plan was filed for the planned flight to Hagerstown Regional Airport (HGR), Hagerstown, Maryland. The flight departed Georgetown County Airport, Georgetown, South Carolina, about 1130.

The pilot reported that prior to departure, the airplane was topped off with fuel. He also received a weather briefing and filed a flight plan with flight service. The airplane was cruising at 9,000 feet to remain above cloud layers during the initial part of the trip. The sky cleared over Virginia and when the flight was approximately 100 miles (30 minutes) from the destination airport, air traffic control (ATC) instructed the pilot to descend to 5,000 feet, which he acknowledged. Although the air had been smooth at 9,000 feet, the airplane descended into moderate to severe turbulence. The pilot reduced throttle to slow to maneuvering speed. When he subsequently added throttle, there was no response as the engine had lost all power. The pilot then pushed the throttle completely forward, which also activated the airplane's fuel boost pump. He positioned the mixture to full rich; however, the engine did not regain power.

The pilot declared an emergency to ATC and the controller provided a vector to the nearest airport. The pilot could not glide to that airport due to mountainous terrain in between. He saw several small fields and was able to land in one of them. During the landing, the airplane struck a fence and trees.

The pilot added that he did not believe the loss of engine power was a mechanical failure as there was no roughness to the engine preceding the event. He believed that it was a fuel or air issue, possibly related to the severe turbulence that he had descended into. The sky was clear and the airplane did not fly through any clouds or precipitation during the descent or prior to the power loss. He thought the right fuel tank was selected when the power loss occurred, but could not be certain. He estimated that the fuel tanks were half-full at the time and he had been switching the fuel tanks every 30 minutes during the flight. He did not switch fuel tanks after the power loss as he was preoccupied with where to land the airplane. Additionally, at the time of the power loss, the mixture had been properly leaned based on turbine inlet temperature.

Examination of the wreckage by a Federal Aviation Administration inspector revealed that during the impact sequence, the left and right wing fuel tanks were compromised and a postcrash fire ensued, which consumed a majority of the wreckage.

The four-seat, low-wing, retractable tricycle-gear airplane, serial number 27-0288, was manufactured in 2000. It was powered by a Lycoming TIO-540, 270-horsepower engine. Review of the aircraft logbooks revealed that the airplane's most recent annual inspection was completed on September 1, 2011. At that time, the airframe and engine had accumulated 1,1,54.5 total hours of operation since new. The airplane had flown approximately 60 hours from the time of the most recent annual inspection, until the accident.

The engine was examined following recovery. The engine remained attached to the airframe via the engine mounts and the propeller had separated from the engine. The engine cowling and cockpit were consumed by fire, as was the fuel system and induction system. The throttle quadrant was identified in the cockpit; however, the cables had separated due to fire and impact damage. The fuel selector was identified and observed in the left main fuel tank position, but the preimpact position of the fuel selector could not be positively determined.

The engine was separated from the airframe for examination. The valve covers, magnetos, fuel nozzles, and top spark plugs were removed. The spark plug electrodes were intact and light to dark gray in color. Fuel nozzle Nos. 1, 3, 4, and 5 were unobstructed. Fuel nozzle Nos. 2 and 6 contained debris consistent with fire damage. The magnetos sustained thermal damage and could not be tested.

The crankshaft could not be rotated by hand. The accessory section was then removed, which revealed thermal and corrosion damage throughout the accessory section and its associated gears. The bottom spark plugs were removed. Their electrodes were intact and light to dark gray in color. The turbocharger wastegate was three-fourths open. The cold section of the turbocharger had been consumed by fire. The hot section impeller housing did not exhibit any rotational scoring.

The fire had melted sections from the bottom of the engine case, including the oil sump with the engine data plate. The exposed sections allowed for borescope access. Holes were drilled on top of the engine case to allow borescope access to that section. The cylinders were also examined with a borescope and no evidence of a catastrophic engine failure was observed with the cylinders, camshaft, or crankshaft.

Airworthiness Directive (AD) 85-24-03 and Mooney service bulletin (SB) M-20-230 noted reports of fuel and water having been found trapped between ribs due to one or more rib drain holes being sealed over during tank sealing, particularly in tanks that have been resealed. Such water could be released during severe turbulence. The AD and SB addressed older model Mooney aircraft and was not applicable to the accident airplane make and model. For the make and model of the accident airplane, the fuel tank inspection called for in the AD and SB was included in the service manual. Review of maintenance records revealed that the accident airplane's right fuel tank had been repaired in 2002 and 2010. Postcrash fire damage precluded the examination of the wing fuel tanks for blockage in the rib drain holes.

NTSB Probable Cause

A total loss of engine power during cruise flight for reasons that could not be determined because of the damage due to the postcrash fire.