History of Flight
On March 11, 2011, about 1343 central standard time, a Cessna 310R, registration N310JR, was substantially damaged after colliding with flat terrain following an uncontrolled descent after takeoff from Smyrna/Rutherford County Airport (MQY), Smyrna, Tennessee. The certificated commercial pilot was fatally injured. Visual meteorological conditions prevailed and no flight plan was filed for the test flight conducted under 14 CFR Part 91.
Radar data from the Federal Aviation Administration (FAA) showed the airplane tracked for about two minutes after departure. It climbed to 3,200 feet mean sea level (msl) on a southerly heading, then appeared at 3,100 feet and then 2,700 feet before no further returns were observed. The targets appeared at 6-second intervals, with the final ones nearly directly above the crash site.
Witnesses described a nose-down, vertical descent. Engine sounds were characterized as "full throttle," "wide open," "really loud," and "never let up on throttle." Others reported the engine was "puttering" or "quit" before the descent. One witness likened the airplane to a "meteorite."
The airplane's owner stated the flight was part of a series of maintenance acceptance flights after installation of a new avionics suite and autopilot. The system tested satisfactorily on the ground but did not function as designed in flight. The avionics technician who performed the installation said the accident flight was the second that day and fourth overall. He accompanied the pilot on the first flight, then after speaking with an autopilot manufacturer representative, conducted another troubleshooting procedure. The technician then left for lunch and the pilot departed alone.
Pilot and Aircraft Information
According to FAA records, the pilot held a commercial pilot certificate with single-engine, multiengine, and instrument ratings. His most recent second-class medical certificate, issued January 12, 2011, required corrective lenses. He reported 13,000 total flight hours at that time. His logbooks were not recovered.
The Cessna 310R received its airworthiness certificate in 1994. Maintenance records indicated 5,515.5 total aircraft hours, with the last annual inspection on June 19, 2010, at 5,439.1 hours.
The avionics technician completed installation of a glass panel and digital autopilot on January 25, 2011. A test flight on March 3, 2011, revealed porpoising when altitude hold or vertical speed modes were engaged. Troubleshooting included installing a new autopilot computer. During that flight, after engaging altitude hold, the airplane descended and the pilot pulled back on the yoke, then disabled the autopilot and electric trim via master switches. The technician informed the pilot that both systems were already off. The pilot later manually trimmed and returned. The technician advised the pilot to read the equipment manuals before further flights. The altitude hold was placarded inoperative, and the airplane was released.
The owner later flew with the pilot from Tupelo to Jackson, Mississippi, and reported that heading and NAV modes worked, but engaging altitude hold caused a nose-down pitch and aggressive descent. The pilot disengaged something, but the owner could not recall what.
Additional work was done. On the accident morning, the pilot and technician conducted another unsuccessful test flight. After landing, the technician contacted the autopilot manufacturer, who instructed disconnecting the flap compensation potentiometer. The manufacturer also shipped a pressure transducer. The technician informed the pilot, stating he wanted to wait for the transducer before another flight, but the pilot chose to fly.
During the March 3 flight, the technician noted the pilot seemed disoriented with the new technology.
An FAA inspector reviewed the Pilot's Operating Handbook (POH), which described four ways to disable the autopilot and two ways to disable elevator trim. A pilot familiar with the POH could disable the autopilot while retaining electric trim function. Review with a manufacturer engineer indicated that a disconnected flap position sensor should not cause an anomaly, and if a pilot pulled back on the yoke with autopilot engaged, trim would run nose-down, requiring additional control effort. At industry standard trim speed, about 12 seconds would elapse from climb to full nose-down.
Previous Damage
On or about October 10, 2010, the pilot taxied the airplane through a drainage ditch, resulting in a left propeller strike and sudden stoppage of the left engine. The damage was reported as minor; no Safety Board investigation occurred. Maintenance records showed extensive repairs to airframe and lifting surfaces, and removal and inspection of the left engine and propeller.
Meteorological Information
At 1356, weather at MQY, 4 nautical miles north of the accident site, reported clear skies, 10 miles visibility, wind from 290 degrees at 9 knots, temperature 14°C, dew point -3°C, and altimeter 30.18 inches of mercury.
Wreckage and Impact
On March 12, 2011, the wreckage was examined. A strong fuel odor was present, and all major components were accounted for. The airplane struck the ground nose-down, 90 degrees vertical, on a mowed grass field, with the wreckage almost entirely within the initial impact crater. Only fragments of sheet metal, plexiglass, and instruments were outside. The crater outline matched the airplane, consistent with vertical descent.
The airplane was excavated using backhoes. Control cable continuity was established from flight control surfaces to the cockpit, with all separations consistent with overload. The elevator trim tab actuator measured in a full "tab up" (nose-down) position. The cockpit was destroyed; only the dual tachometer and fuel gauge were readable. Flap setting and landing gear position (up and locked) were noted.
The left and right engines were recovered from 7 and 10 feet below the surface, respectively. All six propeller blades showed similar twisting, bending, leading-edge gouging, and chordwise scratching. Two right-engine blades were broken, with overload fractures. Fuel was present in the wings.
Engine examination revealed significant impact damage; neither crankshaft nor accessories could rotate. Oil pump covers showed rotational scoring. Fuel pumps were partially separated, with overloaded driveshafts, and contained fuel without water or debris. All four magnetos were separated and destroyed.
Medical and Pathological
The Tennessee medical examiner performed an autopsy, attributing death to multiple blunt force injuries. Toxicological tests by the FAA were negative for drugs or alcohol.