Accident Summary
On September 18, 2016, about 1440 eastern daylight time, a Grumman G-164A, registration N75EP, was destroyed when it was involved in an accident near Chestertown, Maryland. The commercial pilot sustained minor injuries. The airplane was operating under Title 14 Code of Federal Regulations Part 137 as an aerial application flight.
The pilot reported that he ran the engine for 15 minutes on the ground, then taxied to the beginning of a private strip and ran the engine near full power for an additional 5 minutes. Experiencing no anomalies, he conducted a short field takeoff. Immediately after takeoff, when the airplane was just a few feet in the air, he heard a "pop" and felt a vibration, followed by an immediate loss of engine power. The airplane was unable to climb or maintain altitude and settled back to the ground. The pilot was unable to maneuver or stop the airplane in time, and it struck farm equipment and a trailer before skidding to a stop and catching fire.
Background
The day before the accident, on September 17, the airplane was performing aerial agricultural work when the pilot noticed a significant loss of engine power and made a subsequent emergency landing in a corn field. Maintenance personnel inspected the engine and replaced the No. 2 cylinder, adjusted the valves, and test ran the engine. The airplane was subsequently returned to service.
Engine Maintenance History
According to airplane maintenance records, the engine, a Pratt & Whitney Radial R-1340 with installed baffles, was overhauled on July 26, 2011. At that time, Pratt and Whitney Service Bulletin No. 1787 (dated September 7, 1983) and Airworthiness Directive No. 99-11-02 were complied with. This included visual and fluorescent penetrant inspection of cylinders for head cracking and replacement of cracked cylinders. Thereafter, repetitive visual inspections of the cylinders were required every 250 hours.
Subsequent maintenance inspections occurred regularly and within the hourly limits of AD 99-11-02. From overhaul to the accident (5 years), there were eight documented cylinder inspections, and in each case, no defects were noted to the No. 3 cylinder. The most recent inspection compliant with the AD occurred on August 21, 2016, at 761 hours since major overhaul (SMOH), about 74 hours before the accident. The No. 2 cylinder was replaced twice: once on September 13, 2011 at 112.0 hours SMOH, and again on September 18, 2016 at 835.9 hours SMOH, but the reason for replacement was not specified. No other cylinder crack irregularities were noted in the logbook. The entry for the most recent replacement of the No. 2 cylinder did not note that an inspection in accordance with the AD had been completed at that time.
Wreckage and Impact Information
The airplane was taking off from east to west on a private agricultural field about 1,000 ft long. It struck a trailer and farm equipment off the end of the takeoff surface before coming to rest in a large gravel parking area near a hangar. The airplane was impact damaged, the fuselage was consumed by the postimpact fire, and there was significant thermal damage to the engine. Examination of the engine showed that the top of the No. 3 cylinder was fractured and separated near the head of the cylinder. The cylinder was not examined in any further detail.