Accident Overview
On August 9, 2017, at about 1220 eastern daylight time, a Cessna 172S airplane, registration N5274Q, experienced a loss of engine power while maneuvering at low altitude near Wellston, Ohio. The airplane was registered to and operated by KCSI Texas, Inc., conducting an aerial observation flight of a pipeline under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and a company visual flight rules flight plan had been filed. The flight departed Newark-Heath Airport (VTA), Newark, Ohio, about 1330, and was destined for James A. Rhodes Airport (I43), Jackson, Ohio.
During the flight, while maneuvering toward I43 to refuel, the pilot heard a "significant boom" and noticed a reduction in engine rpm. The pilot attempted to regain rpm without success and initiated a forced landing to a green space between trees. During the forced landing, the airplane impacted rolling, uneven grass terrain and a barbed wire fence. The airplane sustained substantial damage to the right wing and fuselage. The pilot and passenger sustained minor injuries.
Engine Examination
Examination of the engine by a Federal Aviation Administration (FAA) inspector noted a large hole on the top of the engine crankcase. The airplane was recovered for further examination. On August 24, 2017, the engine was examined at a recovery facility by a Lycoming Engine representative under the supervision of an FAA inspector. Disassembly revealed a large hole at the top of the crankcase inboard of the No. 4 cylinder. According to Lycoming Engines, the No. 4 connecting rod failed at the small end bushing. The other three connecting rod small end bushings were found displaced forward from their normal positions, and the No. 3 connecting rod small end bushing was free to move by hand.
Maintenance History
A review of the aircraft maintenance records showed the engine was field overhauled on September 2, 2016, at a total time of 2,664.5 hours. During the overhaul, Lycoming LW-13923 connecting rod upper bushings were installed, shipped from the factory on June 30, 2016. The most recent 100-hour inspection was completed on June 15, 2017, at 503.5 hours since major overhaul (SMOH). On July 20, 2017, at 556.4 hours SMOH, the engine oil was changed with no anomalies noted in the oil filter or oil suction screen. The July 2017 oil change record was the last entry in the engine logbook.
Service Bulletin and Airworthiness Directive
On August 4, 2017, Lycoming Engines issued mandatory service bulletin (MSB) No. 632B, concerning identification of connecting rods with non-conforming small end bushings. The MSB stated that LW-13923 connecting rod bushings shipped between November 18, 2015, and November 15, 2016, may be suspected of not meeting specifications and required follow-up corrective action. The MSB included a warning that if a connecting rod bushing becomes unseated, the connecting rod can fail, causing an uncommanded and complete loss of power. Compliance was required within the next 10 hours of engine operation. The FAA issued airworthiness directive (AD) 2017-16-11, effective August 15, 2017, which mandated inspection of connecting rods and replacement of affected connecting rod small end bushings, in accordance with Lycoming Engines MSB No. 632B.