Introduction
On July 12, 2018, at approximately 1647 eastern daylight time, a Cessna A188B (registration N2483J) made a forced landing following a loss of engine power near Rockford, Ohio. The pilot, who owned and operated the aircraft under 14 CFR Part 137 for aerial-application flights, was not injured. The airplane sustained minor damage.
Flight Details
The flight departed at about 1620 from Lakefield Airport (CQA) in Celina, Ohio, for a local aerial-application flight. Visual meteorological conditions prevailed, and no flight plan was filed.
Pilot Report
The pilot reported flying at 350 ft above ground level when the engine began running rough and subsequently stopped producing power. He executed a forced landing to a bean field, resulting in minor damage to the right wing.
Engine Examination
The engine, a 300-horsepower six-cylinder Continental IO-550-D, was examined. A hole was observed in the engine case near the No. 2 cylinder. The engine was shipped to Continental Motors for a teardown examination under NTSB oversight. No external impact damage was found. All six cylinders remained attached with no damage noted.
The crankcase bearing supports exhibited signs consistent with bearing shift. Lock tabs for cylinders No. 2 and No. 3 showed elongation, and all bearing support mating surfaces had varying fretting, with No. 2 and No. 3 surfaces displaying the most. The No. 3 bearing had shifted significantly, with a portion separated. The crankshaft gear was improperly safety wired.
The No. 2 connecting rod was separated from its journal, exhibiting lubrication distress; portions of the rod were found in the sump. The No. 2 connecting rod bearings showed significant thermal damage consistent with heat distress. The No. 2 piston remained in the cylinder but was separated from the connecting rod.
Maintenance History
According to the engine maintenance logbooks, the last major overhaul was on February 2, 2014, with installation on April 1, 2014. All six cylinders were replaced on September 9, 2017, at a tachometer time of 1,225.8 hours; the reason for replacement was not documented. The last annual inspection was on April 2, 2018, at 1,262.0 tachometer hours. The last oil change was on July 8, 2018, at 1,315.6 tachometer hours. At the time of the accident, the tachometer read 1,333.4 hours, meaning 107.6 hours had elapsed since cylinder replacement.
Additional Findings
The induction system remained attached, but several induction coupling clamps were missing, and all induction riser bolts on the inside portion of the attach flange were not installed.