US Patent 10496086 Gas turbine engine fleet performance deterioration

A method for determining gas turbine engine fleet performance deterioration includes receiving data indicative of deterioration parameter values for a plurality of gas turbine engines. The method also includes determining an average deterioration parameter value for each gas turbine engine at a plurality of intervals, and further determining an individual engine slope between the average deterioration parameter value at each adjacent interval for each gas turbine engine. The method also includes determining a fleet average slope between each adjacent interval based on the individual engine slopes between each adjacent interval, the determined fleet average slopes being usable to determine a performance deterioration of a gas turbine engine in the fleet.