What is the duration of the passenger oxygen system on most CRJ 700 aircraft?

• A. 5 minutes
• B. 13 minutes
• C. 20 minutes
• D. 25 minutes

Answer: (B)

During a depressurization, passenger oxygen masks deploy so everyone on board can breathe normally as the cabin altitude rises. The system on most CRJ 700 aircraft is designed to provide oxygen for about thirteen minutes. That duration is chosen to cover the time needed for a safe descent to a breathable cabin altitude (below 10,000 feet) and to give crews time to manage the situation or initiate an evacuation if necessary. The oxygen comes from chemical generators in the masks, which automatically start producing oxygen once the mask is donned and continue for roughly thirteen minutes before the supply is exhausted. The shorter 5-minute option wouldn’t sustain passengers long enough for a typical emergency descent, and the longer 20–25 minute durations aren’t consistent with the system’s capacity and design.