Ever wonder why commercial airliners have oxygen masks? Before taking off, a flight attendant will typically conduct a safety demonstration. He or she will tell passengers to fasten their seatbelt, secure their luggage and place their table trays in the upright position. Additionally, the flight attendant will show passengers where their oxygen masks are located and how to use them.
Commercial airlines have oxygen masks in the event of cabin depressurization. The air in the sky is thinner at high altitudes than at ground or sea level. While this reduces drag and improves fuel efficiency for commercial airliners, it can pose problems for human passengers. Therefore, commercial airliners are equipped with pressurized cabins. As they ascend, the air inside their cabins will gradually pressurize. If an emergency occurs that results in the loss of cabin pressure, however, passengers can access the oxygen masks.
Oxygen masks protect passengers from hypoxia. Hypoxia is a medical condition that’s characterized by insufficient oxygen to the body. Every organ and even every cell in the human body needs oxygen need to survive. Hypoxia involves a lack of oxygen to the body, and it can manifest in the form of a variety of symptoms like fatigue, nausea and dizziness.
Commercial airliners can protect their passengers from hypoxia by offering them oxygen masks. Hypoxia, of course, is typically only a concern if there’s a loss of cabin pressure. When the cabin becomes depressurized, the air inside of the airplane will become thinner and, thus, contain less oxygen. Passengers can then access the oxygen masks while the pilot descends to a safe altitude.
In the United States, the Federal Aviation Administration (FAA) requires all commercial airliners to provide oxygen masks to their passengers if they fly higher than a certain level. Current regulations state that all commercial airliners in the United States must provide each passenger with at least 10 minutes of oxygen for all flights involving flight levels above 250.
A 250 flight level is the equivalent of 25,000 feet altitude. Most commercial airliners fly at about 31,000 to 42,000 feet above sea level, meaning they are higher than the FAA’s specified 250 flight level.
While most commercial airliners have them, oxygen masks often go unused. They simply offer a source of oxygen for passengers if there’s an emergency that causes a loss of cabin pressure. Cabin depressurization will release the oxygen masks above the seats, allowing passengers to easily access them.