Abstract: An Auxiliary Power System includes an APU controller and an aircraft load controller which include an APU load capacity algorithm which provides an uncomplicated and robust method of APU load control. The APU load capacity algorithm defines three load zones: a continuous APU load capacity zone (zone A); a time controlled zone (zone B); and a fault zone (zone C). Each zone is related to altitude to the service ceiling of the APU to provides consistent APU load capacity that addresses APU performance variation and deterioration effects to an end of the APU useful life.

Abstract: An active thrust management system varies pressure responsive to changes in rotor assembly thrust to maintain a desired position. The system includes a bearing supporting rotation of a rotor assembly within a pressurizing chamber. The rotor assembly is supported on a cushion of air generated between the bearing and the rotor assembly. Pressure within a cavity adjacent the rotor assembly opposes a thrust force to maintain a desired position of the rotor assembly. Modulating airflow into the pressurizing chamber adjacent the rotor assembly compensates for changes in the thrust generated by the rotor assembly to maintain the desired rotor assembly position.

Abstract: An exciter circuit for a gas turbine engine delivers a first single high-energy spark followed by subsequent sparks of relatively lower energy to ensures start reliability by specifically clearing ice build-up at the ignition plugs.

Abstract: A dual channel ignition circuit (Channel A and a Channel B). In a start sequence in which a successful ignition event occurs, an exciter controller first energizes only a primary ignition channel (Channel A). Once the exciter controller recognizes a success light-off, the alternate channel (Channel B) will also then be excited as the gas turbine engine is accelerated to a self-sustaining speed. The exciter controller will then switch the primary alternative designation of the channels for the next start attempt. In a start sequence in which an unsuccessful ignition event occurs, the exciter controller sets a fail-to-start on the primary ignition channel on a failure to start A/B counter such that a failed ignition channel is diagnosed without dedicated electronic diagnostic circuits while still attempting to excite both circuits to enhance the dependability of a successful engine light-off.