The ACS Bleed INHB switch is used to:

• A. Improve takeoff and climb performance at high density altitude airports by closing the bleed valve so more air is used to turn the prop rather than pressurize the airplane
• B. Increase cabin pressurization by opening the bleed valve
• C. Open the bleed valve to speed up engine cooling
• D. Disable the bleed system

Answer: (A)

Focusing bleed air usage during takeoff at high density altitude can free engine power for the propeller. The bleed air system pulls air from the compressor to supply cabin pressurization and other systems. That bleed flow adds load on the engine. When you engage the Bleed Inhibit function, the bleed valves close, so bleed air is not drawn off for those uses. With less bleed extraction, the engine doesn’t have to work as hard to maintain engine conditions, leaving more available power to accelerate the prop and improve takeoff and climb performance in hot, high-altitude conditions. This switch isn’t meant to fully disable the bleed system or to speed up cooling; opening the valve would defeat the purpose by increasing the bleed load.