Which component regulates cabin pressure by controlling the air leaving the cabin?

• A. The packs for temperature control
• B. The pressurization controller
• C. The outflow valve
• D. The bleed air valve

Answer: (C)

The key idea is that cabin pressure is controlled by balancing how much air is pumped into the cabin with how much air is allowed to leave. The outflow valve is the component that actually regulates that exit flow, venting cabin air to the outside to maintain the desired pressure and differential pressure. The pressurization controller determines the target pressure and instructs the valve to open or close accordingly, but the physical regulator of leaving air is the outflow valve. The packs provide conditioned air, and the bleed air valve supplies the air to the system, but neither directly controls the amount leaving the cabin.