Accident Details
On April 15, 2013, at approximately 0945 central daylight time, a Beech model N35 airplane, registration N9414Y, was substantially damaged during a forced landing following a loss of engine power after takeoff from the Warren Municipal Airport (3M9), Warren, Arkansas. The pilot and passenger sustained minor injuries. The airplane was registered to and operated by the pilot under 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and an instrument flight rules flight plan had been filed but not yet activated. The flight was originating at the time of the accident, with the intended destination being the Mena Intermountain Municipal Airport (MEZ), Mena, Arkansas.
The pilot reported departing from runway 21 (3,829 feet by 75 feet, asphalt) and climbing to 700 feet mean sea level (msl). As he initiated a right turn to the west, about 1,000 feet msl, the engine lost power. He established a glide in an attempt to return to the airport; however, due to "strong" winds, the airplane contacted the ground "abruptly short of the runway."
Engine Examination
A postaccident engine teardown and metallurgical examination were conducted. The crankcase was cracked starting at the number 1 cylinder head mounting stud and continuing to the top of the case. The number 2 main bearing saddle exhibited longitudinal deformation adjacent to the bore, with fretting and galling on the saddle landings. The other saddles showed curvilinear marks on the split plane landings and helical marks on the saddle bores, consistent with machining marks. When reassembled, the saddle bore diameter at the nose of the crankshaft was measured at 2.5660 inches, exceeding the limit of 2.5625 to 2.5635 inches, in the area centered about 20 degrees from the split plane.
The crankshaft had fractured through the number 3 cheek, immediately aft of the number 2 main bearing journal. The fracture surfaces exhibited curvilinear crack propagation marks consistent with fatigue. The main bearing journal diameters were within limits for a reground crankshaft, except for the number 2 journal. The number 1 main bearing shells were deformed; the number 2 main bearing shells were worn, deformed, and partially split. The remaining bearings exhibited helical lines matching the machining lines on the crankcase main bearing saddles, and the tin coating on the backsides had been worn away except around oil transfer holes. Dimensional inspection of the number 3, 4, and 5 main bearing shells found them within limits.
Maintenance History
Engine maintenance records indicated an overhaul in January 2001 at 1,526.5 hours total time. An annual inspection completed on December 10, 2009, recorded 1,696.7 hours total time (170.4 hours since overhaul). The next entry noted that the engine was removed from the previous airframe "for prop strike on or about 8 – 11" and listed total time as 1,526.5 hours—the same as at overhaul about nine years earlier—while time since overhaul matched the December 2009 annual inspection.
An entry dated January 10, 2012, documented that the engine had been disassembled due to a propeller strike. The crankshaft was magnetic particle inspected with negative findings, and the crankcase mating surfaces were cut with bores resized to manufacturer's limits. The engine was subsequently installed on the accident airplane on March 5, 2013, at which time an annual inspection was completed and the recording tachometer time noted as 216.8 hours. No subsequent entries were found in the airframe or engine maintenance logbooks. After the accident, the recording tachometer indicated 233.31 hours, meaning about 16.5 hours had accumulated since the annual inspection.