Fallon, NV, USA
N517DJ
RAYTHEON AIRCRAFT COMPANY A36
The pilot reported that, during climbout, when the airplane was about 1,000 ft above ground level, the engine lost power. The pilot subsequently maneuvered the airplane to attempt to land on the departure runway. The airplane touched down short of the runway in rough, desert terrain, which resulted in substantial damage to the wings, fuselage, and empennage. A postaccident engine examination revealed that the No. 5 connecting rod cap and one of its two bolts had fractured midlength; the opposite bolt was intact with the nut still fastened. Metallurgical examination revealed that the No. 5 connecting rod had failed due to a fatigue crack that had initiated on the outer surface of the nut-facing boss. The crack propagated inward until the final cross-section of the connecting rod yoke failed in overstress, which then catastrophically breeched the left side of the engine case. The fatigue crack did not show any material imperfections; however, the surface finish of the boss where the fatigue crack initiated was consistent with it having been shot peened. Although shot peening is performed to impart compressive stresses to prevent fatigue crack initiation, excessive peening times may sufficiently alter the surface to create stress concentrators. However, the configuration of the fractured rod yoke precluded any accurate surface roughness measurements and, therefore, it could not be determined if improper surface modification had occurred.
HISTORY OF FLIGHTOn July 10, 2013, about 0445 Pacific daylight time (PDT), a Raytheon Aircraft Company, A36, N517DJ, experienced a catastrophic engine failure during initial climb out, resulting in an off airport landing near Fallon Municipal Airport (FLX), Fallon, Nevada. Silver Sage Aviation was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 135. The commercial pilot and three passengers sustained minor injuries; the airplane sustained substantial damage. The cross-country business flight was departing Fallon, with a planned destination of Dixie Valley, Nevada. Night visual meteorological conditions prevailed, and a visual flight rules (VFR) flight plan had been filed. The pilot reported that during climb out about 1,000 feet above ground level the airplane engine lost power, and he attempted to return to FLX. He was unable to make it, and made a forced landing in the desert adjacent to FLX. The airplane sustained substantial damage to the wings, fuselage, and empennage. AIRCRAFT INFORMATIONThe airplane was a Beech A36, serial number E-3075. The operator reported that at the time of the accident, the airplane had a total airframe time of 1,294 hours. The logbooks contained an entry for an annual inspection dated June 26, 2013. The tachometer read 1,280.1 hours at the last inspection. The tachometer read 1,298.7 hours at the accident scene. The engine was a Continental Motors IO-550, serial number 281690-R. Total time recorded on the engine at the last 100-hour inspection was 5,364.9 hours, and time since major overhaul was 282.3 hours. AIRPORT INFORMATIONThe airplane was a Beech A36, serial number E-3075. The operator reported that at the time of the accident, the airplane had a total airframe time of 1,294 hours. The logbooks contained an entry for an annual inspection dated June 26, 2013. The tachometer read 1,280.1 hours at the last inspection. The tachometer read 1,298.7 hours at the accident scene. The engine was a Continental Motors IO-550, serial number 281690-R. Total time recorded on the engine at the last 100-hour inspection was 5,364.9 hours, and time since major overhaul was 282.3 hours. WRECKAGE AND IMPACT INFORMATIONThe airplane came to rest approximately 600 feet from the departure end of runway 03. The accident site was flat desert terrain. The wreckage was documented at the accident site and recovered. During recovery of the airplane, it was noted that there was a breach of the engine case adjacent to the number five cylinder. TESTS AND RESEARCHInvestigators examined the wreckage at Air Transport, Phoenix, Arizona, on July 30, 2013. The airframe was examined with no mechanical anomalies identified. The engine examination revealed that the number five connecting rod cap and one of the bolts had fractured at midlength, whereas, the opposite bolt was intact with the nut still fastened. The resulting failure continued with a catastrophic breech to the left side of the engine case between the number six and four cylinders. There were no indications of any oil starvation in the engine. There was no assembly discrepancies noted during the examination. The engine was able to be rotated, and continuity was established from the front of the engine to the rear. The airplane was equipped with a JPI 800 engine monitoring system. The unit was removed from the airplane to be sent to the NTSB laboratory for download. The report indicated no abnormalities noted prior to the engine failure. The number five and number six connecting rods, rod end caps, and bolts were sent to the NTSB materials laboratory for further examination. The factual report of the NTSB materials laboratory examination of the engine components is in the accident docket. Examination revealed that the fracture surfaces were a result of fatigue failure of the number five connecting rod.
A fatigue failure of the No. 5 connecting rod, which resulted in a catastrophic engine failure during the initial climb and a subsequent forced landing.
Source: NTSB Aviation Accident Database
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