Which parameters does the ACSC monitor to control bleed valves and distribution?

• A. Duct pressure, valve position, and ESC/Anti-Ice valve position
• B. Duct temperature and cabin pressure
• C. External weather and aircraft speed
• D. Fuel flow and engine RPM

Answer: (A)

The system that controls bleed valves relies on real-time feedback from the bleed-air network itself. Duct pressure is the key signal: it tells the ACSC how much air is actually flowing and whether the pressure in the duct is at the target level for the packs and cabin conditioning. Valve position provides the actual state of the valves—how open or closed they are—so the controller can adjust smoothly and achieve the desired flow. The ESC/Anti-Ice valve position is included because anti-ice needs must be coordinated with the main bleed flow; knowing its valve state ensures anti-ice demands are met without upsetting pack performance or over-pressurizing the system.

Other factors like duct temperature and cabin pressure are important control targets in the overall environmental system, but they aren’t the signals the ACSC uses to regulate bleed valve opening. External weather, airspeed, fuel flow, and engine RPM don’t directly drive bleed-valve control.