What prevents cabin over-pressurization?

What prevents cabin over-pressurization?

• A. Outflow valve
• B. Manual pressure relief latch
• C. Safety valve
• D. Vent door

Answer: (C)

Cabin pressurization is kept within safe limits by a primary regulator that controls how much air leaves the cabin, and a relief mechanism that acts automatically if the pressure would still rise too high. The safety valve serves as that automatic protection: it opens at a set differential pressure to vent cabin air to the outside, preventing the cabin from exceeding the maximum allowable pressure. This backup ensures protection even if the main outflow valve can’t bleed off air quickly enough or if a fault occurs. The outflow valve is the normal regulator for maintaining the desired cabin pressure, while the vent door and manual relief latch are used in other, non-automatic contexts.

Cabin pressurization is kept within safe limits by a primary regulator that controls how much air leaves the cabin, and a relief mechanism that acts automatically if the pressure would still rise too high. The safety valve serves as that automatic protection: it opens at a set differential pressure to vent cabin air to the outside, preventing the cabin from exceeding the maximum allowable pressure. This backup ensures protection even if the main outflow valve can’t bleed off air quickly enough or if a fault occurs. The outflow valve is the normal regulator for maintaining the desired cabin pressure, while the vent door and manual relief latch are used in other, non-automatic contexts.