Accident Overview
On November 24, 2016, about 0850 mountain standard time, a Cessna 182A airplane, registration N6077B, was substantially damaged during a forced landing following a loss of engine power near Safford, Arizona. The commercial pilot and three passengers were not injured.
Flight Details
The airplane was registered to and operated by the pilot under Title 14 Code of Federal Regulations Part 91 as a personal cross-country flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from Safford Regional Airport (SAD) at 0815, with an intended destination of Holbrook, Arizona.
The pilot reported that during cruise flight at 8,500 ft mean sea level, he noticed the oil pressure began to fluctuate and decided to return to the airport. When the airplane was about 4 miles north of SAD, the engine lost power, and he initiated a forced landing to an area of open desert. During the landing roll, the airplane struck two dirt berms, and the nose wheel collapsed.
Damage and Engine Examination
Post-accident examination by a Federal Aviation Administration inspector revealed substantial damage to the forward portion of the fuselage structure.
An engine examination was conducted on July 13, 2017, under the supervision of the National Transportation Safety Board investigator-in-charge. All engine accessories except the carburetor remained attached. Two holes in the crankcase above the number 5 and 6 cylinders were observed, and silicone was present around the crankshaft nose seal.
The crankcase exhibited normal operational signatures except for mechanical damage surrounding the number 5 and 6 cylinder bays. Crankcase main bearings #1, #2, and #4 showed normal wear, while #3 main bearing had wear into the copper layer. The camshaft had mechanical damage to the cylinder 5 and 6 lobes. The number 5 crankshaft connecting rod bearing journal showed thermal discoloration and mechanical damage; number 6 had slight mechanical damage.
During disassembly, cylinders 1–4 were normal, but cylinder 5 had mechanical damage to the skirt, with the piston and pin separated from the connecting rod. Cylinder 6 also had a damaged skirt; the connecting rod cap was separated, and the bolt was missing with an elongated hole.
The number 5 and 6 pistons, rings, pins, and connecting rods were sent to the NTSB Materials Laboratory. Examination revealed damage consistent with post-fracture operation. Both connecting rod bolts from cylinder 5 were fractured at mid-length with necking, consistent with tensile overstress. The cylinder 6 connecting rod bolts also fractured at mid-length with necking, exhibiting a 45° slant consistent with tensile overstress. The piston from cylinder 5 had fractures emanating from the piston pin boss, consistent with overstress failure of aluminum castings.
Logbook Review
Review of the engine logbooks showed that the engine was overhauled on May 20, 1996, at a tachometer time of 3,686 hours. The most recent 100-hour/annual inspection was completed on October 19, 2016, at an engine time since overhaul of 1,556.9 hours.