What happened
On May 2, 2010, a JetProp DLX Piper PA-46-350P, registration N135CC, crashed near New Albany, Indiana, resulting in 2 fatal injuries. The flight departed from Barkley Regional Airport in Paducah, Kentucky, en route to Bowman Field Airport in Louisville, Kentucky, operating under an instrument flight rules (IFR) flight plan.
At the time of the accident, the aircraft was flying in instrument meteorological conditions (IMC) with light rain and low ceilings. Radar data indicated that the aircraft was at 4,000 feet and flying at 131 knots before the airspeed began to decrease. In the final minute of recorded radar data, the airspeed dropped from 119 knots to approximately 57 knots while the altitude fluctuated between 3,800 and 3,900 feet.
A witness observed the aircraft approaching from the southeast with a loud engine sound, after which the airplane went upside down and entered a spiral nose-dive. There were no further radio transmissions from the crew before the impact.
The investigation
Post-accident examination of the wreckage showed the aircraft was in an upright position upon impact. The left wing tank was broken, and the right wing had separated mid-span. The engine, a PT6A-34, showed evidence of rotation at the time of impact, and the propeller blades were consistent with impact damage.
An examination of the autopilot system revealed that the roll monitor and yaw fail errors were logged, which occur when the aircraft experiences high roll or yaw rates. The autopilot automatically disconnects when these thresholds are exceeded. Additionally, the clutch in the roll servo was found to slip at 31 inch per pound, which exceeded the STC installation limit of 22 +/- 2 inches per pound.
Engine trend monitor data showed a torque exceedance and a shaft horsepower exceedance shortly before the accident. The investigation also noted that the pilot had recently completed JetProp Factory Training and had only accumulated approximately 14 hours of flight time in this specific aircraft. It was noted that the pilot had been advised to accumulate more hours under visual flight rules (VFR) before flying in IMC to gain familiarity with the cockpit layout.