The two safety valves in the aft bulkhead protect against which conditions?

• A. Over pressurization and negative pressure.
• B. Positive pressure fluctuations only.
• C. Temperature spikes
• D. Humidity spikes

Answer: (A)

The main idea is that these valves protect the cabin from dangerous pressure differences. The two safety valves in the aft bulkhead are there to handle both ends of the pressure spectrum: they vent air if the cabin pressure becomes too high (over-pressurization) and they admit outside air if the cabin pressure drops too low (negative pressure). This keeps the cabin’s differential pressure within safe limits, preventing structural stress or seal failure during altitude changes or a leak. The other options don’t describe how pressure safety valves function, since they relate to temperature or humidity, which these valves don’t control.