Grumman G-164A N4638 accident near Fergus Falls, Minnesota

Probable cause

A total loss of engine power due to a cracked No. 2 cylinder head.

NTSB analysis

The pilot was spraying a large corn field when he saw a puff of white smoke come from the engine. He turned toward a road, but about half way through the turn, the engine lost all power. The pilot jettisoned the chemical load and landed in the corn field. Examination of the radial engine revealed the No. 2 cylinder head was cracked. A review of the maintenance logbooks revealed that a mandatory Federal Aviation Administration Airworthiness Directive that required a 100-hour visual inspection to prevent cylinder head cracking, had been complied with at the last annual inspection, but no entries were made that any cracks were observed.

Text from the NTSB. Open the NTSB docket for CEN12LA491 for the full record.