Air Tractor Inc AT-401 N7315P accident near Carroll, Iowa

Probable cause

The wear-related failure of the airframe fuel boost pump, which resulted in fuel starvation and a loss of engine power.

NTSB analysis

The commercial pilot had completed half of a planned aerial application of a field when the airplane’s engine lost power. The pilot performed a forced landing to a field which resulted in substantial damage to both wings. Postaccident examination of the airplane revealed the inline airframe fuel boost pump would not provide normal fuel output due to wear of the pump motor shaft and leakage of the pump seal. The pump also did not bypass fuel during the on-scene examination but did bypass fuel during testing at the pump manufacturer. The differences in bypass test results were most likely due to plumbing differences between the airplane and the test fixture. The pump manufacturer recommended a 10-year overhaul of the pump and did not provide an hours-in-service overhaul recommendation. The pump was manufactured in 2007, and an airplane logbook record indicated it had been last overhauled in 2013.

Text from the NTSB. Open the NTSB docket for CEN21LA319 for the full record.