Failure Analysis of a CH-47 Horizontal Hinge Pin Assembly, P/N 114RS226

Report No. ARL-TR-4011
Authors: Marc Pepi; Gary Wechsler
Date/Pages: December 2006; 38 pages
Abstract: A CH-47D horizontal hinge pin assembly was examined to determine the root cause of ring and roller fracture and spalling. Chemical analyses, metallography, and hardness testing indicated that the rings and rollers conformed to the material requirements of the governing drawing. Metallography and visual and scanning electron microscopy indicated the failure likely initiated in the lag ring due to rolling contact fatigue because of high-service loads.
Distribution: Approved for public release
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Last Update / Reviewed: December 1, 2006