How do the pressurization safety valves operate?

How do the pressurization safety valves operate?

• A. Pneumatically, spring-loaded
• B. Electrically, solenoid-actuated
• C. Hydraulically, pressure-driven
• D. Manually by crew

Answer: (A)

Cabin pressurization safety valves are automatic relief devices. They stay closed by a spring, and opening is driven by pneumatic pressure once the cabin differential pressure reaches a dangerous limit. A pneumatic actuator pushes the valve open to vent air, and when pressure drops below the set point the spring closes it again. They operate independently of crew input and without relying on hydraulics, delivering a failsafe means to prevent over-pressurization.

Cabin pressurization safety valves are automatic relief devices. They stay closed by a spring, and opening is driven by pneumatic pressure once the cabin differential pressure reaches a dangerous limit. A pneumatic actuator pushes the valve open to vent air, and when pressure drops below the set point the spring closes it again. They operate independently of crew input and without relying on hydraulics, delivering a failsafe means to prevent over-pressurization.