NTSB Factual Report

On July 6, 2003, about 1030 Pacific daylight time, a Bell 47 G5, N7938J, made a forced landing following an uncontained engine failure near Salinas, California. During the forced landing, the main rotor flexed downward and severed the tail boom. Gomes Farm Air Service, Inc., was operating the helicopter under the provisions of 14 CFR Part 137. The commercial pilot, the sole occupant, was not injured; the helicopter sustained substantial damage. The local aerial application flight departed Salinas, about 1030. Day visual meteorological conditions prevailed, and no flight plan had been filed. The primary wreckage was at 36 degrees 40 minutes north latitude and 121 degrees 45 minutes west longitude.

The pilot reported he had made several passes during an aerial application flight. While on the downwind leg the engine shuttered violently then quit. The pilot performed a run-on landing. During the landing sequence the main rotor blade made contact with the tail boom of the helicopter severing the tail rotor gearbox. The engine of the helicopter was externally inspected and the aft section of the engine case was ruptured.

The pilot said that they had experienced the same type of failure 3 years ago. The engine on the accident helicopter had 623 hours since last overhaul.

The pilot/owner reported that upon examination of the engine they found brass shavings in the oil and oil filter. The # 3 piston connecting rod had broken in flight which resulted in the total loss of power.

NTSB Probable Cause

The failure of a piston connecting rod during an aerial application, which resulted in a total loss of engine power and subsequent forced landing.