What does the flight abort mode of the pressurization system do?

• A. Immediately depressurizes the cabin to provide fresh air.
• B. Maintains cabin altitude at sea level for 5 minutes.
• C. Holds the departure airport elevation setting for 10 minutes after takeoff or 6000 feet above takeoff field elevation.
• D. Switches to external air source only.

Answer: (C)

Flight abort mode in the pressurization system is designed to keep the cabin environment stable during a rejected takeoff by locking the cabin altitude to the departure airport’s elevation for a set period after takeoff (ten minutes) or until the aircraft climbs 6000 feet above the takeoff field elevation. This prevents a rapid rise in cabin altitude or a large differential pressure right after an abort, reducing passenger and crew discomfort and avoiding stress on the aircraft structure while the situation is being resolved.

The other options describe actions that don’t occur in abort mode: unloading air to the cabin immediately for a “fresh air” feel would be unsafe and uncomfortable; maintaining sea-level cabin altitude for several minutes isn’t how the system is designed to operate post-takeoff abort; and switching to an external air source only would neglect proper pressurization control and conditioning of the cabin.