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The need for Air Turbine Starter (ATS) condition monitoring is driven by industry demand for continuous improvement in reliability and reduction in repair and overhaul costs. This paper discusses issues for condition monitoring of Air Turbine Starters (ATS), including the need for condition monitoring, selection of monitoring parameters, current projects, and goals for future designs. The USAF is currently conducting a program to develop a simple, stand-alone device capable of indicating impending failures. This device will likely focus on a combination of temperature monitoring and magnetic chip detection. Future ATS condition monitoring devices should be capable of more comprehensive evaluation of starter parameters.

A noncontacting clearance seal consists of a series of centrifugal air pumps and oil/air separators for air turbine starters on the BR710 and the CFM56-5 engines. Conventional contacting seals for rotating shafts are limited in life due to the formation of oxidized oil coke buildup on the sealing surfaces. The clearance seal directly addresses the problem of viscous heat generation in carbon face and lip seals by eliminating contact. Standard contacting seals typically have local temperature increases of 50 to 75 °F higher than the gearbox sump oil. Heat generation by the clearance seal is minimized, resulting in a significant increase in reliability compared to a standard contacting seal. The reliability increase is estimated for various flight-hour-to-start-cycle ratios in air turbine starter gearboxes.