Recommended Maintenance, Inspection and Monitoring Procedure for Engine Test Cells ARP8540

Issuing Committee: Eg-1e Gas Turbine Test Facilities And Equipment

Rationale: Scope: A guide to maintenance procedures in test cells. A suggested equipment monitoring and/or inspections to reduce the probability of unanticipated failures and associated test cell down time. Guidelines for using typically available data acquisition capabilities in a test cell are provided to utilize normally available trending capability to monitor the testing equipment in addition to using these tools for the usual monitoring of the test article. For the common types of test cells (turboshaft, turboprop, turbojet, and turbofan) test facilities, lists of typical systems with their associated components are provided with suggested inspection intervals and key items to look for in the inspection. A template risk assessment form is provided to facilitate the customization of the assessment of the test cell components to help predict recommended spares. Rational Test cells are typically on the critical path for most organizations that have test cells. Failure of a critical component in test cell can result in the facility being down from a relatively minor time period of a few hours or days to the normally intolerable time period of multiple months. Given the expense of building and maintaining a test cells few organizations have significant surplus redundant capacity. It is very common that even if an organization has multiple test cells, each test facilities can only run a small subset of the various engines. This makes the test cell very often a single point of failure in the organization’s plans to pass off overhauled engines, perform the initial production test for an engine or various tests in engine development/improvement programs. Given the cost of much of the equipment in a test cell much of the larger more complicated equipment and the time to install replacement equipment it is deemed not practical to address failures by the stocking of spares for much of the test equipment. Reliance on the OEM of the test equipment for these recommended practices assumes several things that in most cases are moderate to high risk assumptions. These assumptions would include: • That the equipment OEM will still be in business and available to support the equipment • That the equipment will be used within the operational envelope that the equipment designer anticipated as normal. (Given the nature of use of many test cells, the abnormal use may be more frequent OR less frequent than “standard”.) • That the equipment OEM’s recommended procedures did not omit key components • That the various subsystems of the test cell do not interact with each other in a manner that impacts each other. Use of recommended inspection and maintenance procedures can reduce the risk should the above identified assumptions and other not specified assumptions prove to not be true.