What is the function of the pressurization system?

• A. Maintains stable fuel temperature.
• B. Maintains a safe cabin altitude during flight.
• C. Controls the doors for evacuation.
• D. Regulates cockpit humidity.

Answer: (B)

The main idea here is that the pressurization system keeps the cabin at a safe, breathable altitude as the aircraft climbs. Since outside air pressure drops rapidly with altitude, the system maintains a controlled cabin altitude (often around 6,000–8,000 feet) by adding conditioned air and venting excess air through the outflow valve to keep the internal pressure differential within safe limits. This prevents hypoxia for passengers and crew and reduces structural stress on the fuselage during high-altitude flight. Temperature and humidity inside the cabin are managed by the environmental control system, but those are separate functions; the pressurization system’s primary job is controlling cabin pressure, not fuel temperature or door operations.