North American AT-6D N150U accident near Henley, Missouri

Probable cause

The pilot’s decision to conduct extended inverted flight, which resulted in a total loss of engine power due to fuel flow disruption. Contributing to the accident was his decision to conduct aerobatic maneuvers at low altitude, which precluded him from selecting a suitable landing site following the total loss of engine power.

NTSB analysis

The airline transport pilot reported that, about 30 minutes into the local flight, the engine experienced a total loss of power, and he conducted a forced landing to a powerline cut. He stated that the airplane was at low altitude at the time of the loss of engine power because he had been taking photos of a friend's farm.

Two witnesses observed the airplane conducting aerobatic maneuvers during the flight. One of the witnesses stated that the airplane was flying so low that it startled her horses as it passed overhead. She then observed the airplane roll inverted; shortly thereafter, the engine became silent. The airplane lost altitude while still inverted and impacted trees. Examination of the wreckage revealed no preimpact mechanical malfunctions or anomalies that would have precluded normal operation. The airplane's operating instructions stated that, "Inverted flying must be limited to 10 seconds because of engine difficulties resulting from prolonged inverted flight." Because no anomalies were found during the examination, it is likely that the loss of engine power was a result of fuel disruption to the engine during the extended inverted flight.

Text from the NTSB. Open the NTSB docket for CEN16LA222 for the full record.