Accident Overview
On December 11, 2016, at approximately 1300 eastern standard time, a Beech A36, registration N69286, was substantially damaged following a total loss of engine power during cruise flight and subsequent ditching in the Long Island Sound near Shoreham, New York. The private pilot and a passenger were not injured. The airplane had departed from Long Island MacArthur Airport (ISP), New York, and was destined for Westfield-Barnes Regional Airport (BAF), Massachusetts. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under 14 CFR Part 91.
According to the pilot, after reaching a cruise altitude of 5,500 feet, the engine began running rough. The pilot moved the mixture, propeller, and throttle controls to full forward, but the engine continued to run roughly and worsened. He decided to turn back to ISP. During the turn, oil covered the windscreen. The pilot declared an emergency and requested radar vectors to Igor I. Sikorsky Memorial Airport (BDR) in Bridgeport, Connecticut. Air traffic control advised a turn north to 360°, but the pilot struggled to keep the wings level and declined. He then requested vectors to Calverton Executive Airpark (3C8) in Calverton, New York. The controller indicated 3C8 was 7 miles ahead.
The engine still produced partial power, and the pilot believed they could reach the airport. Seconds later, he observed parts—believed to be from the propeller—separating from the airplane. The engine then lost all power, and the pilot informed the controller they would ditch in the sound. The airspeed indicator read 80 knots just before water contact. After ditching, the pilot and passenger opened the door, egressed, swam to a nearby rock, and awaited rescue.
Examination of Wreckage and Engine
A Federal Aviation Administration inspector examined the wreckage, finding damage to the right wing spar and multiple holes in the engine crankcase. The crankshaft front section was fractured, and the propeller was not recovered.
The engine, a Continental IO-550-B1A, was sent to the manufacturer for teardown. Examination revealed fatigue cracking on the #4 main bearing journal and fracture surfaces, with crack arrest and beach marks. Crankcase mating surfaces showed fretting at the #1 through #4 main bearing journal case halves. The #4 bearing journal surface was obliterated; the #3 main bearing journal had lock slot elongation. All six connecting rods exhibited lubrication distress. Significant metal debris from bearing material and crankcase was found in the oil sump and on the oil pickup tube screen. Through bolt breakaway torque values were low.
The crankshaft was forwarded to the NTSB Material Laboratory. Binocular microscope examination showed fatigue crack arrest marks. Scanning electron microscopy revealed the fatigue crack origin contained mechanical damage from relative movement between fracture faces, obscuring fine crack origin features.
Maintenance History
According to FAA and aircraft maintenance records, the airplane received its airworthiness certificate on February 18, 1984, and was registered to the owner on October 9, 2014. It was powered by a Continental IO-550-B1A engine. The most recent annual inspection was conducted on June 10, 2016, with a recorded time in service of 1,648.3 hours. The engine had six new cylinders installed on May 21, 2012, accumulating 163.8 hours of service at the time of inspection.