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The USAF T56 engine Program Office has adopted a unique maintenance approach which utilizes the concept of complete system reliability in order to optimize their cost of workscoping aircraft gas turbine engines. While classical Reliability Centered Maintenance (RCM) focuses on the actual reliability and failure modes representative of a particular system, its benefits are limited since it only describes individual system components9. The workscope cost optimization program provides the user with recommended optimal repair workscopes based on the underlying reliability and cost of repair options. This maintenance concept is based upon the methodology documented in SAE Aerospace Recommended Practice (ARP) JA6097, which is a “Best Practices Guide” established to provide direction in objectively determining which other maintenance to perform on a system when that system requires corrective action, with the goal of improving overall system reliability at the lowest possible cost.

Small media ingestion has been known to cause erosion and result in corrosion to compressor components of gas turbine engines. Compressor degradation negatively impacts fuel consumption, engine performance, reliability, and maintenance costs. Power losses in the compressor section are often unrecoverable without increasing fuel consumption; therefore, protecting the compressor from excessive erosion/corrosion may extend the life of an engine, and reduce fuel, maintenance costs, and emissions. A study was conducted to investigate the effect of a new compressor blade and vane erosion/corrosion resistant coating on two Rolls-Royce T56-A7-B engines. The study included a comprehensive sand ingestion test that compared the performance and hardware condition of uncoated and coated compressor airfoils before, during, and after sand ingestion of 135 pounds of sand mixture.