The accessory cooling system supplies cooling air to the generator. The system has a NACA scoop installed in the inlet. The NACA scoop takes intake air and sends it to the generator through a duct system. The air is removed from the generator through an outlet duct. The outlet duct is a part of the frangible coupling fitting that attaches the generator to the gearbox.

The intake duct is a fixed duct installed in the bottom of the nacelle inlet between the outer barrel and the aft bulkhead. The intake duct has a NACA scoop and a two-part intake duct. The two-part intake duct is made of two equally shaped sections, bonded together. The intake duct is made from carbon ply with an additional copper mesh layer in the NACA scoop for lightning protection. The different parts are bonded together to make a full intake duct.

The intake duct is attached to the outer barrel by twenty rivets. The interface between the NACA scoop and the outer barrel, and the NACA scoop and the intake duct are filled with sealant. Where the intake duct passes through the aft bulkhead, the interface is sealed with a sealing plate and sealant.

The generator cooling duct is a flexible duct that is installed between the front end of the generator and the intake duct. Each end of the generator cooling duct is attached by hose clamps.

The outlet duct is an exhaust duct that sends the used air from the generator overboard. The outlet duct is integral to the quick-access-disconnect (QAD) that attaches the generator to the gearbox. The outlet duct is installed through an opening in the lower fan-cowl door.

When the aircraft moves, air is pulled in by the NACA scoop. The air passes along the intake duct and the generator cooling duct, and supplies cooling for the generator. Used air is then removed through the outlet duct.

The accessory cooling system interfaces with the following systems/components:

• Main Generators
• Gearbox
• Air Intakes

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