The portion of the powerplant system which directs airflow to the engine. Does not include integral structure with the airframe, which shall be included in the applicable structures JASC chapter. Typical parts are carburetor air heat doors, alternate air doors, linkages, controls, filter element, ducts, hose, air box, latch, seals, nose ring cowls, scoops, compressor fan cowls, compressor fan case, buried engine ducts, vortex generators, actuators, control handles, cables, wiring, plumbing, doors, warning systems, position indicators, etc.