Besides warning lights or bells, what action may the cabin altitude warning system trigger?

• A. Relays to activate cabin lights to full bright
• B. Open the crew door
• C. Reduce cabin pressurization
• D. Shut down engines

Answer: (A)

When cabin altitude rises to alarming levels, the warning system’s job is to grab attention and prompt a quick crew response. In addition to lights or bells, it can energize other cues to make the warning unmistakable. One such cue is using relays to drive the cabin lights to full brightness, so the warning is hard to miss even if the crew isn’t directly looking at the indicators. The other options aren’t typical automatic actions of a cabin altitude warning system: opening the crew door is unsafe and not a function of the warning system; automatically reducing cabin pressurization or shutting down engines are not standard automatic responses of the cabin altitude warning circuitry.