Diamond DA42 N988JA

During a training flight in the multi-engine airplane, at an altitude of about 5,000 ft mean sea level (msl), the flight instructor and pilot receiving instruction simulated a loss of right engine power by shutting down the right engine. After feathering and securing the engine, they subsequently attempted to restart it, but reported that the engine would not produce power. The airplane continued to descend and the pilots ultimately chose to perform a forced landing to a field, during which the airplane slid into a ditch, resulting in substantial damage to the fuselage. The pilot-rated passenger, who was observing the flight from the back seat, reported that “there seemed to be confusion on roles and responsibilities” between the instructor and the pilot receiving instruction, and he did not recall any checklist items being called out between the two pilots. The passenger reported that the right engine appeared to be running, but at a lower rpm than the left engine, and that the right propeller continued to turn throughout the descent and forced landing. The fuel and oil pressure gauges for the right engine were indicating “in the green range.” At an altitude around 1,500 ft msl, the flight instructor took control of the airplane for the forced landing. Postaccident examination of the airplane did not reveal evidence of any preimpact failures or malfunctions that would have prevented normal operation. At the accident site, both engines’ mixture control levers were found in the full rich position, the propeller control levers were found in the fine pitch/high rpm position, the electric fuel pumps were in the “on” position, and the fuel selectors were in the “on” position. Both propellers were found in the fine pitch/high rpm position. Test runs of both engines revealed no anomalies that would have prevented normal operation. Review of the airplane flight manual indicated that, given the atmospheric conditions at the time of the accident, with one engine properly secured (propeller feathered) and the other engine operating at maximum continuous power, the airplane would have been able to maintain a positive rate of climb. The airplane flight manual stated that, if it was not possible to restart an engine in flight, the engine securing procedure should be accomplished. The positions of the engine controls and propellers after the accident, along with the passenger’s observations of the right propeller turning and the right engine fuel and oil pressure gauges, and his observation of a lack of checklist usage, indicate that the attempted engine restart was likely not done in accordance with the manufacture’s prescribed procedures and was consistent with a failure to properly secure the right engine after the pilots’ determination that it was not producing power. It is likely that the windmilling condition of the right propeller, which would have produced significant drag, was the reason that the airplane was unable to maintain altitude. Had the instructor followed the published procedure after the right engine could not be restarted, it is likely that the flight could have returned to an airport and landed without incident.

Quoted verbatim from the NTSB record.