CEN14LA030

The pilot reported that, during climbout, he noticed that the engine was vibrating. After leveling off the airplane, the vibration worsened, and the engine subsequently experienced a total loss of power. The pilot executed a forced landing onto a road, and the airplane impacted a fence post. Examination of the engine revealed that the crankshaft was fractured through the No. 8 cheek position between the Nos. 5 and 6 pistons. Fatigue cracking emanated from the connecting rod journal where the No. 5 connecting rod mates. The No. 6 piston cooling nozzle was not found in its position, and its pieces were found in the bottom of the sump; the pieces were more intact than would be expected if they had been ground between the crankshaft and connecting rod for an appreciable amount of time. Also, there was no evidence of a gouge or other mechanical damage on the No. 5 connecting rod journal. Based on this evidence, it is unlikely that the fatigue cracking was initiated by the No. 6 cooling nozzle being lodged against the crankshaft after falling out of position. About 18 months before the accident, the engine was repaired and overhauled due to a propeller strike. Further, about 4 months before the accident, maintenance personnel performed a top overhaul of the engine, and, about 1 month before the accident, maintenance personnel replaced the No. 2 cylinder. The timing of the failure suggests that an imbalance could have been introduced to the engine during one or both of the maintenance procedures, which could have resulted in the initiation of the fatigue cracking and the subsequent falling out of the No. 6 cooling nozzle; however, the exact cause of the crankshaft fatigue cracking could not be determined.

On October 14, 2013, about 1700 central daylight time, a Piper PA-32R-300 airplane, N5605V, was substantially damaged during a forced landing near Hector, Arkansas. The two pilots received minor injuries and the two passengers were not injured. The airplane was registered to and operated by Baxter Flying Incorporated under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Day visual meteorological conditions prevailed for the flight, which operated on an instrument flight rules flight plan. The flight originated from Fayetteville Executive Airport (FYV), Fayetteville, Arkansas about 1615 and was destined for Tunica Municipal Airport (UTA), Tunica, Mississippi. According to the pilot, the engine was vibrating during the initial climb. After leveling the airplane at 9,000 feet mean sea level (MSL), the vibration worsened and the engine experienced a total loss of power. The pilot executed a forced landing onto a rural road, during which the right wing contacted a fence post. The airplane was recovered to the facilities of Dawson Aircraft, Inc., near Clinton, Arkansas. The engine was subsequently removed and shipped to Mena Aircraft Engine, near Mena, Arkansas, for examination. During engine teardown, the crankshaft was observed to be fractured through the #8 cheek position, between the #5 and #6 pistons. The fatigue cracking emanated from the connecting rod journal, where the #5 connecting rod mates. The #5 cylinder skirt was damaged, which prevented removal of the cylinder from the crank case. The #6 cylinder skirt was damaged, which made it difficult to remove from the crank case. The #3 piston had multiple abrasions on the piston skirt. The #1, #2, #4 pistons were removed without difficulty and had no anomalies. Several of the cam shaft tappet bodies (mushroom shaped) were fractured. Ferrous shavings were present in the oil sump and oil filter and the oil suction screen was completely blocked with metal shavings. The #6 piston cooling nozzle was not in position and the cooling nozzle pieces were found in the bottom of the sump. These pieces of the cooling nozzle were relatively intact. The #2 and the #4 cooling nozzles were measured below their specified torques. #1 and #3 cooling nozzles were torqued correctly. Torque for the #5 cooling nozzle was not measured, since the #5 piston could not be removed from the crank case. The crankshaft, attached counterweight, connecting rod journal bearing, and #6 piston oil cooling nozzle pieces were shipped to the National Transportation Safety Board materials laboratory for examination. The crankshaft's fracture surface was observed to have repeated crack arrest marks consistent with fatigue cracking. No gouges or wear were observed at the fatigue cracking initiation area and no evidence of thermal distress was visible on the #5 connecting rod journal. No evidence of a gouge or other mechanical damage from a wedged piece of metal wearing against the crankshaft was observed onthe #5 connecting rod journal. The #5 connecting rod bearing had a 'M03' code stamped on the sides that indicated it mated with a ground or reworked crankshaft connecting rod journal. The measured dimensions of the mating #5 connecting rod journal met the requirements for the diameter expected following rework. On April 20, 2012, the engine was repaired and overhauled following a propeller strike. After magnetic particle inspection of steel parts, replacement of several components and a test run, the engine was returned to service with the original crankshaft. On June 22, 2013, a top overhaul was performed, based on owner comments of a rough running engine that was using oil. On September 18, 2013, the #2 cylinder was honed and a new piston was installed, after a compression check revealed zero compression and a broken #2 piston ring.