In most aircraft installations the PT6 is mounted so that the intake end of the engine is towards the rear of the aircraft, leading to it being known by many as the "back-to-front" engine. This places the power section at the front of the nacelle, where it can drive the propeller directly without the need for a long shaft. Intake air is usually fed to the engine via an underside mounted duct, and the two exhaust outlets are directed rearward. This arrangement aids maintenance by allowing the entire power section to be removed along with the propeller, exposing the gas-generator section. To facilitate rough-field operations, foreign objects are diverted from the compressor intake by inertial separators in the inlet. In some installation such as the PT6A-66B version in the Piaggio Avanti P180, the engine is reversed, with the propeller acting as a "pusher", the accessory gearbox facing the front of the aircraft.