ERA18FA244 · Cessna 335

The pilot, who was the owner of the airplane, was conducting a personal cross-country flight with one passenger. Recorded engine data indicated that, about 9 miles from the destination airport, the left engine lost all power for about 2 minutes. Power was restored for about 2 minutes before it was lost again as the airplane was on a left downwind leg abeam the approach end of the runway. The right engine's power output remained relatively constant for the remainder of the flight. The airplane continued the downwind leg for about 20 seconds, then began a left descending 180° turn. Data recovered from the primary flight display indicated that, at the end of this turn, the airspeed decreased to 73 knots (kts), below the airplane's published minimum control speed of 83 kts, and the airplane rolled inverted and descended into the ground.

The pilot did not hold a valid pilot certificate at the time of the accident, as his certificate had been revoked about 21 years earlier. Although the pilot had owned the airplane for about 7 years, he had logged only 1.8 hours in the preceding eight months, and 6.4 hours during the prior calendar year. The most recent documented practice of one engine inoperative (OEI) procedures was over 6 years before the accident, and there was no record of any flight reviews in his logbook; therefore, it is unlikely that the pilot was proficient in the procedures associated with OEI at the time of the accident, which included the criticality of maintaining minimum control speed (Vmc) and not turning into the nonoperational engine.

Examination of both engines revealed no anomalies that would have precluded normal operation and the right engine's recorded data parameters and propeller exhibited signatures consistent with the engine operating until impact. Although the engine monitor's recorded parameters indicated the left engine lost power immediately before the accident, it lacked sufficient parameters to determine why the loss of engine power occurred. Given the available fuel onboard, the airplane had adequate fuel to complete the accident flight; however, the pilot's management of the fuel during the flight and whether it contributed to the loss of left engine power could not be determined.

Although autopsy of the pilot revealed evidence of severe coronary artery disease, the recorded flight data indicated that he continued to fly the airplane after both losses of power in the left engine; therefore, it is unlikely that sudden impairment or incapacitation from an acute cardiac event contributed to the loss of control. The pilot may have been experiencing effects from his use of diphenhydramine, such as psychomotor slowing and impaired judgment. However, based on the available information, whether effects from his use of diphenhydramine contributed to this accident could not be determined.

Verbatim NTSB analysis and probable cause from the NTSB dataset