When must passenger oxygen masks be deployed?

Passenger oxygen masks must be deployed at cabin altitudes above 14,000 feet because, at these elevations, the atmospheric pressure is significantly reduced, leading to inadequate oxygen levels for normal breathing. This can cause hypoxia, where the body does not receive enough oxygen, which can impair cognitive function and physical abilities. The deployment of oxygen masks ensures that passengers receive supplemental oxygen to maintain their health and safety during flight when the cabin environment can no longer support adequate oxygenation naturally. Thus, regulations and safety protocols mandate that oxygen masks be available and deployed under these specific conditions to safeguard passengers and crew in the event of a sudden loss of cabin pressure or when flying at high altitudes.