Which document would you consult to confirm altitude guidance when both packs are inoperative?

Which document would you consult to confirm altitude guidance when both packs are inoperative?

• A. AFM
• B. MEL
• C. QRH
• D. FCOM

Answer: (A)

When a system fault limits how you operate, rely on the Aircraft Flight Manual for the official limits and guidance. The AFM is the definitive source for operating procedures and performance data for abnormal conditions, including when environmental control is inoperative. If both packs are down, the AFM’s environmental control section tells you what altitude you can operate at safely and how to manage cabin pressurization, which is the core of altitude guidance in this scenario. The Quick Reference Handbook is meant for quick, step-by-step actions you take in the moment, but it does not replace the official altitude guidance published in the AFM. The MEL tells you whether the fault is permissible for flight and under what conditions, rather than prescribing the altitude limits. The FCOM offers deeper system descriptions, but the AFM remains the primary, authoritative reference for the altitude guidance you need when packs are inoperative.

When a system fault limits how you operate, rely on the Aircraft Flight Manual for the official limits and guidance. The AFM is the definitive source for operating procedures and performance data for abnormal conditions, including when environmental control is inoperative. If both packs are down, the AFM’s environmental control section tells you what altitude you can operate at safely and how to manage cabin pressurization, which is the core of altitude guidance in this scenario.

The Quick Reference Handbook is meant for quick, step-by-step actions you take in the moment, but it does not replace the official altitude guidance published in the AFM. The MEL tells you whether the fault is permissible for flight and under what conditions, rather than prescribing the altitude limits. The FCOM offers deeper system descriptions, but the AFM remains the primary, authoritative reference for the altitude guidance you need when packs are inoperative.