Accession Number : AD0767243
Title : U. S. Army Helicopter Hydraulic Servocylinder Reliability and Maintainability Investigation
Descriptive Note : Final rept.
Corporate Author : SYSTEMS ASSOCIATES INC LONG BEACH CA
Personal Author(s) : Huffman, James L ; Dockswell, Sheldon
PDF Url : AD0767243
Report Date : May 1973
Pagination or Media Count : 148
Abstract : The report describes an investigation carried out to identify, isolate, and verify the causes of problems with hydraulic servocylinder actuators used on U.S. Army helicopters, and to trace the resulting effects on helicopter availability. Design requirements, quality assurance provisions, maintenance procedures and practices were analyzed to assess their impact upon the current problems. The analysis of the pertinent failure data and documentation revealed that five failure modes were responsible for over 90% of the total hydraulic servocylinder removals in a 6 1/2-year period. Subsequent analysis of the various policies, practices and procedures showed that these documents contain anomalies that contribute to the occurrence of the five predominant failure modes. The lack of stringent basic design requirements, quality control, and adequate maintenance manuals was shown to be a major contributor to the leaking failure mode. This mode accounts for approximately half of the servocylinder removals from U.S. Army helicopters.
Descriptors : *FLIGHT CONTROL SYSTEMS, *HELICOPTERS, *HYDRAULIC ACTUATORS, FAILURE(MECHANICS), HYDRAULIC SERVOMECHANISMS, HYDRAULIC VALVES, LOGISTICS, MAINTAINABILITY, MAINTENANCE, SPARE PARTS, VALUE ENGINEERING
Subject Categories : Helicopters
Hydraulic and Pneumatic Equipment
Distribution Statement : APPROVED FOR PUBLIC RELEASE