NTSB Factual Report

On May 8, 2005, at 0916 Pacific daylight time, a restricted category Grumman G-164C, N6535K, force landed in a rice field after a loss of engine power near Willows, California. Chuck Jones Flying Service, who was also the registered owner of the airplane, was operating it under the provisions of 14 CFR Part 137. The commercial pilot was not injured; the airplane sustained substantial damage. Visual meteorological conditions prevailed and no flight plan was filed for the local area agricultural application flight.

According to the pilot, while seeding rice over a field, the engine lost partial power. The pilot force landed the airplane in a field. During the landing roll, the landing gear impacted a berm and were sheared from their structural attachment points on the airplane. Until the ground impact, the engine was producing partial power, but not enough to sustain flight.

The Federal Aviation Administration accident coordinator reported that the number 5 cylinder piston had fractured at the piston pin boss. The piston pin, which is mounted in the piston pin boss and holds the piston to the connecting rod, fell from the boss and the connecting rod was free to rotate. Following the accident, the piston was jammed in the cylinder barrel and had to be cut from the engine for removal. The engine was overhauled about 1,154 hours prior to the accident. The maintenance history on the piston could not be determined based on available records.

NTSB Probable Cause

the loss of engine power due to the fractured piston pin boss on the number 5 cylinder.