Patent ID: 7805947

Claim:
An aircraft gas turbine engine, comprising a fan, a high pressure compressor, a combustor, a high pressure turbine connected to the high pressure compressor by a core shaft, a low pressure turbine connected to the fan by a fan shaft, and an engine gearbox fitted with: an integrated drive generator (IDG) normally connected to the engine gearbox; an engine driven pump (EDP) normally connected to the engine gearbox; a fuel pump normally connected to the engine gearbox; a hydro-mechanical unit (HMU) connected to the fuel pump; and an oil pump normally connected to the engine gearbox, wherein the IDG includes: an IDG clutch which can be controlled to connect the IDG with or disconnect the IDG from the engine gearbox, such that the IDG is normally connected with the engine gearbox and the IDG can be disconnected from the engine gearbox for ground test and troubleshooting of the IDG and as a means to prevent damage to the IDG and the aircraft gas turbine engine in certain flight emergency cases; an IDG cranking pad which allows a motor to drive said IDG when said IDG is disconnected from the engine gearbox for ground test and troubleshooting of the IDG without running the aircraft gas turbine engine in its entirety; and an IDG air turbine clutch which can be controlled to connect the IDG with or disconnect the IDG from an air turbine, such that the IDG is normally disconnected from the air turbine and when the IDG is disconnected from the engine gearbox, the IDG can be connected with the air turbine for the air turbine to drive the IDG to provide back-up electric power in certain flight emergency and abnormal conditions and as a means to ground test and troubleshoot said IDG without running the aircraft gas turbine engine in its entirety; and when the IDG is connected with the engine gearbox, the IDG can be connected with the air turbine for the air turbine to drive the aircraft gas turbine engine through the IDG and the engine gearbox as back-up starter on ground and in flight.