Accident Overview
On May 30, 2013, at 1628 eastern daylight time, a Cessna 182P, registration N6525M, was substantially damaged during a forced landing following a total loss of engine power while in cruise flight near Brevard, North Carolina. The private pilot incurred minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the flight, which departed Paulding Northwest Atlanta Airport (PUJ) in Atlanta, Georgia, about 1520. The personal flight was conducted under 14 CFR Part 91.
Pilot Report
According to the pilot, while in cruise flight at 9,500 feet above mean sea level (msl), he heard a "loud noise," the manifold pressure gauge needle "rotated," and then heard a "bop-bop-bop" sound. During the subsequent descent and search for a forced landing site, he smelled smoke and observed engine oil trailing down the outside of the airplane. The engine continued to produce power intermittently until losing all power around 5,000 feet msl, about 3,000 feet above ground level. At the time of the engine power loss, the airplane was over a private airstrip in Brevard, North Carolina.
Forced Landing
The pilot maneuvered the airplane for landing on runway 4, but the runway was obstructed by cars and farm equipment harvesting hay from the airport property. After touching down, the pilot maneuvered the airplane into a small knoll between the airport and an elementary school, where it struck a berm and came to rest.
Post-Accident Inspection
Inspection of the airplane at the accident site by a Federal Aviation Administration (FAA) inspector revealed substantial damage to the engine firewall, but no obvious reason for the loss of engine power. The airplane was retained for a detailed examination.
Pilot Information
The pilot held a private pilot certificate with a rating for airplane single engine land. His most recent third class medical certificate was issued August 31, 2011. The pilot reported 1,500 total hours of flight experience, of which 500 hours were in the accident airplane make and model.
Aircraft Information
According to FAA and maintenance records, the airplane was manufactured in 1975. Its most recent annual inspection was completed July 1, 2012, at 8,209 total aircraft hours. The airplane was equipped with a Continental O-470S engine with Superior Air Parts Millennium cylinders installed at its most recent overhaul. The engine's most recent overhaul was performed on November 1, 2000, and the engine had accrued 590 total flight hours since that date.
Engine Examination
Initial inspection of the engine revealed no obvious engine damage, so the engine was prepared for a test run by replacing the damaged propeller, plumbing a can of fuel into the fuel system, and using an external battery for engine start. The engine started immediately and idled, but made a "popping sound." The engine was stopped, and closer inspection revealed that the number 2 exhaust push rod tube was broken and leaked oil. The number two cylinder was removed; the exhaust valve was found stuck in the closed position and the push rod was found to be worn through into the oil channel, and fractured at the midpoint. The cylinder and its associated parts were shipped to the NTSB Materials Laboratory in Washington, DC.
Detailed Findings
Detailed examination of the cylinder and its associated parts showed that the exhaust valve was stuck in the closed position. The exhaust pushrod was bent and fractured near its midpoint, and the fracture signatures were consistent with compressive loading. The pushrod was worn through approximately 60 percent of its diameter. Examination of the cylinder revealed that the opening of the exhaust valve guide appeared circular, but the hole was not concentric with the exterior of the guide. The center of the hole was offset toward the center of the cylinder relative to the guide center axis. The measurements and the wear patterns exhibited a misalignment of the valve guides and the contact between the pushrod, rocker arm, valve stem, valve head, and seat. The cylinders were delivered fully assembled to the overhaul facility, and a search of the FAA Service Difficulty Report database revealed no reports for the engine cylinder assembly.