Aircraft Engine Control Mode Analysis

This paper describes the control mode analysis procedure that is used to establish closed-loop control requirements for advanced aircraft propulsion systems. The procedure utilizes anticipated variations in engine component performance, engine deterioration, and control tolerances in a statistical analysis to establish corresponding variations in engine output performance and safety parameters. Potential closed-loop control configurations are evaluated by this process, compared, and the best configuration selected for implementation into control law and schedule designs. A byproduct of the analysis is the establishment of engine design and performance margins. The paper will describe typical engine variational models used in this process, the General Electric COMET program designed to automate the analysis, and typical mode study results based on a current augmented turbofan engine.