Implications of engine deterioration for creep life

World developments have led the armed forces of many countries to become mo re aware of how their increasingly-stringent financial budgets are spent. O ne major expenditure for military authorities is upon aero-engines. Deterio ration of an engine generally results in a lower specific thrust and higher specific fuel-consumption for the same spool speeds and turbine-entry temp eratures. In order to meet the thrust requirement for the same aircraft's p erformance, the engines are ran at higher spool speeds and/or turbine-entry temperatures. This results in greater rates of fuel consumption, and a sho rter life (due to the greater creep damage and low-cycle fatigue incurred). Possessing a better knowledge, of the impacts of engine deterioration on a n aircraft's operational performance as well as its fuel and residual life- expectancy, helps the users to improve engine utilization. (C) 1998 Elsevie r Science Ltd. ALI rights reserved.