Accident Overview
On October 27, 1009, at approximately 1700 mountain daylight time, a Cessna 210, registration N5464E, was substantially damaged when it nosed over and impacted terrain following a loss of engine power near Walsh, Colorado. The aircraft was registered to and piloted by an airline transport-certificated pilot, who was the sole occupant and sustained minor injuries. Visual meteorological conditions prevailed, and the personal flight was conducted under Title 14 Code of Federal Regulations Part 91 with a filed and activated VFR flight plan.
Pilot and Flight
The cross-country flight originated at Ulysses, Kansas, at approximately 1730 central daylight time, and was en route to Farmington, New Mexico. According to the pilot, while in level cruise flight at 6,500 feet mean sea level, he detected a slight smoke smell. Oil pressure and oil temperature readings were normal, but the exhaust gas temperature (EGT) on one cylinder dropped, followed shortly by EGT decay on another cylinder. The pilot diverted toward Springfield, Colorado, Municipal Airport but was forced to make an emergency landing in an open field near Walsh.
Emergency Landing
Recent rains had softened the ground. When the nose wheel touched down, the airplane nosed over. The aircraft sustained substantial damage.
Post-Accident Examination
An FAA airworthiness inspector examined the engine at the scene and noted that the cylinder hold-down studs on the lower side of the number 2 cylinder had threads, but one stud had snapped off. The wreckage was released to the owner’s attorney on January 20, 2010, and the engine was transported to Air Salvage of Dallas for disassembly and examination on March 2, 2010, with NTSB and FAA representatives present. The NTSB air safety investigator observed that it appeared the lower four nuts on the number two cylinder were not properly torqued, which allowed the lower side of the cylinder to move while the upper part remained fixed. A crack developed on the right side of the cylinder and propagated along the bottom lip to the left side, eventually leading to failure.
Maintenance History
Examination of maintenance records revealed that on August 21, 2009, during the annual and 100-hour inspections, all six cylinders were removed due to low compression and replaced with overhauled cylinders, new pistons and rings, and new gaskets and seals. At the time of the accident, airframe total time was 3,797.79 hours, and time since engine major overhaul was 1,239.82 hours. The tachometer reading at the accident site was 3,059.41 hours.