Accident Overview
On June 31, 2015, at about 1130 central daylight time, a Grumman G-164A aircraft, registration N963X, impacted terrain after the engine lost power near Emmett, Kansas. The aircraft was registered to and operated by Precision Aerial Ag LLC of Seneca, Kansas, under 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed, and no flight plan had been filed. The local flight originated from Wamego, Kansas, at approximately 1100.
Pilot Account
According to the pilot's accident report, while making a spray run, he heard a loud "bang" and saw a puff of smoke emit from the upper right-hand side of the engine. The propeller then seized. The pilot executed a forced landing in a brome field. During the landing, the aircraft collided with bushes and nosed over. The pilot, the sole occupant on board, received minor injuries.
Engine Examination
On-site examination by Federal Aviation Administration inspectors revealed several loose cylinder stud nuts and hold-down bolts that appeared to have been pushed up on the cylinder skirt. Several studs, particularly those on the number 4 cylinder, were stretched and looked to be nearly pushed out of the engine crankcase. One cylinder was about to separate from the crankcase.
Maintenance History
Examination of the engine maintenance logbook showed the engine had received a major overhaul on February 13, 2007. On March 10, 2010, Airworthiness Directive (AD) 99-11-02 was complied with by inspecting the cylinder heads. On March 2, 2011, February 22, 2012, May 30, 2013, and May 13, 2014, AD 56-06-02 was complied with by inspecting the cylinder hold-down studs. On July 15, 2014, the engine and propeller were removed due to a blower bearing failure. After reinstallation on August 10, 2014, and again on March 18, 2015, the cylinder bases and heads were checked for cracks and loose studs. At the time of the last inspection, the tachometer read 6,730 hours, and the engine had accrued 506.68 hours since major overhaul.
The accident site was located at 14624 A4 Road, Emmett, Kansas.