When cabin doors are not properly closed on a jet transport, what is the usual signaling method?

When cabin doors are not properly closed on a jet transport, what is the usual signaling method?

• A. Audible alarm
• B. Warning light
• C. Master caution indicator
• D. Red beacon

Answer: (B)

The signal is a dedicated warning light. When a cabin door isn’t fully secured, the door interlock system triggers a visual alert on the flight deck or cabin control panel, illuminating a warning light to catch the crew’s attention quickly. This visual cue is reliable in any lighting and lets the crew verify the door status at a glance and take corrective action. While audible alerts may occur on some aircraft, the common and most direct signal for this condition is the warning light. Other indicators like master cautions or external beacons serve broader or different warning purposes and aren’t the standard signal for a door left ajar.

The signal is a dedicated warning light. When a cabin door isn’t fully secured, the door interlock system triggers a visual alert on the flight deck or cabin control panel, illuminating a warning light to catch the crew’s attention quickly. This visual cue is reliable in any lighting and lets the crew verify the door status at a glance and take corrective action. While audible alerts may occur on some aircraft, the common and most direct signal for this condition is the warning light. Other indicators like master cautions or external beacons serve broader or different warning purposes and aren’t the standard signal for a door left ajar.