At what cabin altitude do the passenger oxygen masks automatically deploy?

The correct answer is associated with the operational safety standards established for cabin pressurization in commercial aircraft. Passenger oxygen masks automatically deploy when the cabin altitude reaches 14,000 feet. This altitude threshold is set to ensure that passengers receive supplemental oxygen in scenarios where cabin pressure has lost integrity, as above this altitude, the lack of sufficient cabin pressure can lead to hypoxia, which is a dangerous condition due to insufficient oxygen levels.

Understanding that 14,000 feet is a critical threshold helps illustrate the regulatory focus on passenger safety and physiological limits of the human body regarding oxygen availability. It is crucial for the aircraft systems to automatically respond at this altitude to protect passengers and crew if a depressurization event occurs.

Other options represent altitudes where oxygen requirements may change, but do not trigger automatic deployment of masks. For instance, while 10,000 feet is notable as a point where pilots have to consider supplemental oxygen for themselves, it is below the critical threshold for passenger mask deployment. Similarly, the thresholds of 12,000 feet and 16,000 feet do not align with the established safety protocols found in aviation procedures for automatic mask deployment.