Grumman G 164B N311AL accident near Sac City, Iowa

Probable cause

The loss of engine power for reasons that could not be determined based on the available information.

NTSB analysis

The airline transport pilot reported that he changed the engine oil the night before the accident flight. The next day, he performed a normal engine run-up and then departed on the agricultural application flight. The airplane's tail lifted when the airplane reached 60 mph, and the airplane then accelerated to 80 mph. Shortly after getting airborne, the pilot felt that the airplane was not performing as it should be and that the engine power was decreasing. He advanced the engine controls full forward and selected a cornfield for the forced landing.

The pilot reported that he thought that the engine's blower/supercharger had failed because the engine did not stop but did seem to lose power. An engine examination was not performed; therefore, the reason for the loss of engine power could not be determined.

Text from the NTSB. Open the NTSB docket for CEN15LA377 for the full record.