Under what conditions may you be dispatched on a revenue flight with the aircraft pressurization system inoperative?

Under what conditions may you be dispatched on a revenue flight with the aircraft pressurization system inoperative?

• A. Only with oxygen system
• B. Only with special permit
• C. Never
• D. Only with MEL authorization

Answer: (C)

Cabin pressurization is required for safe flight at typical jet operating altitudes. If the pressurization system is inoperative, the cabin would not be held at a breathable, safe pressure, and relying on emergency oxygen for an entire cruise isn’t feasible for passengers and crew for the duration of a revenue flight. The oxygen system is intended for sudden decompression, not to substitute for a full-time pressurization system. There’s no MEL item or special permit that authorizes dispatch with the pressurization system inoperative for a revenue flight. Therefore, it is not permitted to fly revenue with this system failed; the aircraft must be repaired before dispatch.

Cabin pressurization is required for safe flight at typical jet operating altitudes. If the pressurization system is inoperative, the cabin would not be held at a breathable, safe pressure, and relying on emergency oxygen for an entire cruise isn’t feasible for passengers and crew for the duration of a revenue flight. The oxygen system is intended for sudden decompression, not to substitute for a full-time pressurization system. There’s no MEL item or special permit that authorizes dispatch with the pressurization system inoperative for a revenue flight. Therefore, it is not permitted to fly revenue with this system failed; the aircraft must be repaired before dispatch.