Which component automatically modulates cabin pressure using sensor feedback in the 787?

Which component automatically modulates cabin pressure using sensor feedback in the 787?

• A. Outflow valve
• B. Pressurization controller
• C. Cabin pressure relief system
• D. Automatic vent valve

Answer: (B)

The key idea is that cabin pressure is kept by a closed‑loop control system that uses real-time sensor feedback. The pressurization controller acts as the brain, continuously reading cabin altitude and differential pressure from sensors and comparing them to the commanded pressure profile. It then adjusts the outflow valve position to vent more or less air from the cabin, so the actual pressure follows the target while staying within safe limits. The outflow valve is the actuator, not the controller itself, so it won’t regulate pressure without the controller’s commands. The cabin pressure relief system serves only as a safety backup to vent pressure if limits are exceeded, not for routine modulation.

The key idea is that cabin pressure is kept by a closed‑loop control system that uses real-time sensor feedback. The pressurization controller acts as the brain, continuously reading cabin altitude and differential pressure from sensors and comparing them to the commanded pressure profile. It then adjusts the outflow valve position to vent more or less air from the cabin, so the actual pressure follows the target while staying within safe limits. The outflow valve is the actuator, not the controller itself, so it won’t regulate pressure without the controller’s commands. The cabin pressure relief system serves only as a safety backup to vent pressure if limits are exceeded, not for routine modulation.