The Air Drive Unit (ADU) 2000 incorporates the most advanced design standards and concepts in air drive technology. It was specifically designed for the Boeing 767-400ER aircraft. Each of the six system sub-assemblies were custom designed and were not derivatives of existing production hardware. The ADU 2000 is a high capacity (120 HP) turbine driven gearbox, and its associated control elements, used to power a hydraulic pump to meet aircraft peak hydraulic power demands. The system components consist of a modulating and shut off valve, turbine gearbox assembly exhaust muffler, and electronic control card