US Patent 11702954 Monitoring engine operation

A method is provided for an engine. During this method, a database is provided for a parameter of the engine. The database includes a plurality of values for the parameter determined over a period of time. Confidence bands are established using a probability density function on the database. An action is performed in response to a comparison of a first updated value for the parameter to the confidence bands. The engine may be configured as a gas turbine engine or another type of heat engine.