Full Authority Digital Electronic Control (FADEC) - Augmented Fighter Engine Demonstration

This paper describes continuing development of the Navy sponsored General Electric (GE) FADEC program as demonstrated by operation of a uniquely configured F404 advanced fighter engine. This engine is a low bypass ratio, variable compressor geometry twin spool turbofan with afterburner. The General Electric FADEC, described in this paper, was programmed to operate with standard F404 control strategy and upon external command to shift to a strategy producing automatic control of a Variable Cycle Technology (VCT) feature, a Rear Variable Area Bypass Injector (RVABI). The FADEC microprocessor was also programmed to provide Failure Indication and Corrective Action (FICA) that utilizes a real time engine model to calculate and substitute replacement values (as required) for sensed values of fan speed, core speed, compressor discharge pressure, compressor inlet temperature, low-pressure turbine discharge temperature, and main engine fuel flow. Actuator Failure Indication and Corrective Action (AFICA) and adaptive starting fuel scheduling were also demonstrated at the General Electric Co., Lynn, Massachusetts (sea level test), and at Naval Air Propulsion Center (altitude test), Trenton, New Jersey. Emphasis of this paper will be placed on demonstrated fault tolerant capabilities of the digital control system as related to input sensors.