NTSB Factual Report

On September 19, 2009, about 0815 Pacific daylight time, an experimental Cassutt III M, C-FDXO, made a forced landing at Reno Stead Airport, Reno, Nevada. The pilot/owner was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The airline transport pilot sustained serious injuries; the airplane sustained substantial damage from impact forces. The local air race flight departed from Reno Stead at 0800. Visual meteorological conditions prevailed, and no flight plan had been filed.

The pilot’s crew chief reported that during an air race 2 days prior to the accident, a SCAT tube from the oil cooler separated in flight, and the engine overheated. He stated that, during a post race examination, the maintenance crew could hear the synthetic oil boiling, and observed globs of oil being ejected from the engine breather tube. He noted that it took the engine about 6 hours to cool before they were able to work on it. They drained the remaining oil, and checked the oil screen, which contained no debris. They examined the cylinders internally with a borescope, and noted no damage. In addition, the crankshaft rotated freely. They changed the oil, and the crew chief instructed the pilot to monitor the temperature closely during the next race.

During the accident race, the pilot reported that the engine was overheating, but turning. He elected to perform a precautionary landing on runway 14. As he was on the base leg to the runway, the engine stopped rotating, and the airplane began sinking rapidly. The airplane landed hard about 50 yards from the approach end of the runway.

Examination of the airplane revealed that the airframe tubular steel structure buckled, and sustained substantial damage. Oil was along the right side of the fuselage.

The central portion of a connecting rod and bearing pieces were located within the debris surrounding the wreckage. The fracture surfaces at both ends of the rod piece were angular and irregular; the connecting rod piece was also twisted.

Examination of the engine by the Safety Board investigator-in-charge (IIC) revealed a hole in the crankcase above cylinders number one and two. All cylinders were secure to the crankcase on their base. There was oil in the oil sump and oil screen. The oil screen contained debris; a magnet attracted some of the debris.

The crankshaft could be rotated manually. The IIC noted movement of the numbers one, three, and four cylinders’ piston. The number two piston did not move in the barrel. Investigators removed cylinders number two and four, and split the crankcase.

The main bearings were in proper position. The connecting rod for cylinder number two fractured and separated about 1 inch below the piston wrist pin. The remaining portion of the connecting rod was twisted and discolored. The piston end of the connecting rod rotated freely; the crankshaft end of this connecting rod fractured and separated from the crankshaft. Its pieces exhibited blue discoloration, and the fracture surfaces exhibited mechanical peen damage. The crankshaft journal for cylinder number two connecting rod exhibited a blue discoloration, as did the camshaft journal. The number two connecting rod bearings exhibited a blue discoloration and were smeared.

NTSB Probable Cause

The loss of engine power due to failure of the No. 2 connecting rod as a result of operation of the engine at excessive temperatures.