U. S. Army Helicopter Hydraulic Servocylinder Reliability and Maintainability Investigation.

摘要

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. (Author)