The IPAS provides pressurized air to aircraft pneumatic systems. Bleed air is drawn from two ports: a high-pressure port is exclusively used to pressurize the hydraulic systems, and a low-pressure port is used by all other consumers. Low-pressure air is used by the engine air turbine starters, fuel boost and transfer pumps, anti-ice system, ice detection probe, nitrogen inerting unit, vapor cycle cooling system, and environmental control system. IPAS bleed air can be provided by one or both engines, the APU, or an external source such as an AGPU.
