Accident Overview
On March 14, 2020, at approximately 1315 central daylight time, a Cessna 182 airplane, registration N20847, sustained substantial damage during a forced landing accident near Baxterville, Mississippi. The pilot and two passengers were not injured. The flight was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Pilot Report
The pilot reported that about 10 minutes after departure, at an altitude of approximately 1,500 ft mean sea level, the engine experienced a sudden reduction in power. All instrument gauges appeared normal, and the engine continued running smoothly but produced a different sound and insufficient power to maintain altitude. The pilot turned on the electric fuel pump and selected both the PRIME and ON positions, with no change in engine performance. A magneto check showed only a slight drop per side. Unable to maintain altitude, the pilot attempted to divert to IH Bass Jr Memorial Airport (4R1) in Lumberton, Mississippi, but continued to lose altitude.
Forced Landing
The terrain in the area consisted of rolling hills and forested land. The pilot selected a dirt road that veered right, adjacent to a clear-cut field, for a forced landing. After touchdown, while trying to make a right turn to follow the road, the airplane ground looped and went backwards into a tree line. The airplane collided with numerous trees during the accident sequence, resulting in substantial damage to the fuselage, empennage, and both wings.
Engine Examination
The tachometer read 5,182.1 hours at the time of the accident. A postaccident examination revealed that a portion of the No. 1 cylinder intake valve head was missing, and the inside of the cylinder sustained impact damage. The cylinder was removed, and the intake valve was sent to the NTSB Materials Laboratory for metallographic examination.
Metallurgical Findings
The examination showed that the combustion face of the valve exhibited impact marks uniformly across the face. A portion of the valve head had fractured due to inward propagation of a radial rim fracture, followed by initiation and propagation of a chordal fracture in the fillet area perpendicular to the valve stem axis. The initial crack developed at the rim and propagated inward toward the valve head center as a radial rim crack. When the crack front reached the fillet region, a second crack initiated and propagated in fatigue as a chordal fracture. A final overstress fracture occurred near the rim. Adjacent to the keeper/collet groove, chafe marks were present around the valve stem circumference, indicative of valve floating. Impact marks and rim damage on the valve seat were consistent with foreign object damage. The seat revealed impact wear scars and deformed machining marks; no indications of seat erosion were noted.
Maintenance History
A review of engine maintenance records showed that a repaired No. 1 cylinder was installed on May 9, 2014, at tachometer time 4,584.1 hours. The partial maintenance release stated the repair process included refaced valves and three-angle cut valve seats. No other entries related to the No. 1 cylinder were found. Annual inspections were completed every year after this cylinder installation. Repaired cylinders for Nos. 2, 3, and 4 were installed in 2015.