1-13. Combustion Section. combustion section (fig. 1-6) consists of two compressor discharge
air tubes (one on each side of engine), a combustion outer case, and a combustion liner. A spark igniter
and fuel nozzle are installed in the rear of the outer combustion case. Compressor discharge air is
ducted from the diffuser scroll to the combustion outer case by the two compressor discharge air tubes.
Air enters the single combustion liner at the rear through holes in the liner. The air is mixed with fuel
sprayed from the fuel nozzle and combustion gases move forward out of the combustion liner to the
1-14. Power and Accessory Gearbox. The main power and accessory drive gear trains (fig. 1-7) are
enclosed in a single gear case. The gear case serves as the structural support of the engine. All engine
components, including the engine-mounted accessories, are attached to the case. The reduction gearing
reduces power turbine speed from 35,000 to 6000 rpm at the output drive pads.