N112MBRockwell International 112 · 1974

On June 18, 2016, about 1235 eastern daylight time, a Beech P35 airplane, N112MB, ditched in Block Island Sound after a total loss of engine power near Westerly, Rhode Island. The private pilot received minor injuries. Visual meteorological conditions prevailed and a visual flight rules flight plan was filed, but not activated, for the personal flight. The airplane was owned and operated by the pilot and the flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. The flight originated from Francis S. Gabreski Airport (FOK), Westhampton Beach, New York, with an intended destination of Taunton Municipal Airport (TAN), Taunton, Massachusetts.

In an interview with a Federal Aviation Administration (FAA) Inspector, the pilot stated that while en route, he attempted to reduce the manifold pressure, however it did not respond. Next, he heard a "loud bang," followed by oil covering the windscreen of the airplane, and the engine lost total power. Furthermore, the pilot reported that the propeller rpm "was all over the place" prior to the total loss of engine power. He ditched about 2 miles west of Westerly State Airport (WST), Westerly, Rhode Island. After landing in the water, the pilot egressed without incident, and the airplane sank.

The airplane was recovered and an examination revealed that the wings, empennage, and fuselage sustained substantial damage during the accident sequence. In addition, a hole was noted in the top of the engine crankcase.

According to FAA records, the airplane was manufactured in 1962 and was powered by a 260-hp Continental Motors, Inc., IO-470-N21B reciprocating engine. The airplane's most recent annual inspection was completed on December 29, 2015, at a recorded tachometer reading of 2,812 hours, airframe total time of 5,186 hours, and engine time since major overhaul of 99 hours. The pilot indicated that, at the time of the accident, the engine had accumulated 109 hours of engine time since major overhaul.

The engine was equipped with an F&M Enterprises Inc. (model C6LC-L) oil filter adapter, which was not original equipment, but could be installed on the engine under FAA Supplemental Type Certificate (STC) number SE09356SC. The oil filter adapter installation was completed on December 1, 2011, which was the same time as the engine overhaul. A review of the oil filter adapter manufacturer's installation instructions revealed that, during installation, the oil filter adapter body was torqued to 65 ft lbs, and it should be retorqued after 10 hours of operation. The oil filter adapter required one fiber gasket and one copper crush gasket to be used in the installation. In addition, manufacturing guidance indicated that at each annual inspection or 100-hour inspection, the mechanic was to inspect the oil filter adapter for oil seepage, the safety wire, the security of the adapter, and record the results of the inspections in the logbook.

Maintenance guidance for the oil filter adapter included instructions for replacing the gaskets anytime the oil filter adapter was removed from the engine and reinstalled, and at 300 hours or 3 years, whichever occurred first. The most recent maintenance on the oil filter adapter recorded in the engine logbook was completed on August 25, 2012, at an engine time since major overhaul of 40 hours.

An examination of the engine revealed that the oil filter adapter tightening break away torque was 13.58 ft lbs and the loosening torque was less than 13.33 ft lbs, as the torque wrench would not register any lower torque. Furthermore, the fiber gasket located between the adapter and the engine was torn and partially extruded from the adapter. The oil filter adapter was removed and the fiber gasket was removed. The fiber gasket was torn in one location and the crush deformation not symmetrical around the gasket. In addition, the Nos. 2 and 4 connecting rods had separated from the crankshaft. All connecting rod journals exhibited thermal damage and signatures consistent with lubrication distress.