At what altitude must passenger oxygen masks be automatically released in the event of cabin depressurization?

Passenger oxygen masks must be automatically released in the event of cabin depressurization at an altitude of 15,000 feet. This altitude is critical because above 15,000 feet, the oxygen levels in the atmosphere decrease significantly, making it difficult for individuals to obtain enough oxygen for safe breathing. The use of supplemental oxygen is essential to prevent hypoxia, a condition that can impair cognitive and motor functions, and can quickly become life-threatening.

Regulations and safety standards established by aviation authorities require that oxygen systems be available and functional above this altitude to ensure the safety and well-being of passengers. The automatic deployment of masks at 15,000 feet ensures that passengers have immediate access to oxygen in case of a loss of cabin pressure, allowing them to breathe comfortably and safely until the aircraft descends to a lower altitude where breathable air is available.