“Ladies and Gentlemen, In the unlikely event of a loss of cabin pressure, the pilots have really cool quick-donning, pressure demand oxygen masks. You, on the other hand, have a yellow Dixie cup with an elastic band. Enjoy the flight!”
What’s the difference between the two types of masks? What exactly are they supposed to do?
A typical airliner flies at 35,000 feet, give or take a few thousand. Inside, passengers enjoy a pleasant 72ºF at a cabin altitude of about 5,000 feet above sea level. Perfect for snacking, chatting and napping.
Outside the aircraft is another story. On the other side of your window is an environment completely incompatible with human life. The temp is a bone chilling -40ºF, but the real trouble is the high altitude. Our lungs need a lot of atmospheric pressure to collect sufficient oxygen. At cruise altitude, more than half the weight of the atmosphere is well below you. In an unpressurized aircraft at cruise altitude, your lungs can’t provide your brain with enough oxygen without a little help. Fortunately, the airplane’s pressurization system takes care of this for us.
Airplanes are extremely reliable, but just in case…
If there’s a problem with the aircraft’s pressurization system (it’s very rare), everyone onboard the airplane will need supplemental oxygen. That’s what the orange oxygen masks are for. During a pressurization malfunction, the air pressure inside the cabin starts to decrease (the altitude that your body “feels” starts to climb). If the change in pressure is fast enough, you may feel your ears pop. As the cabin pressure climbs above 14,000 feet, the famous yellow masks will drop down. If this happens, you might think you can breathe okay, but trust me – put the mask on because your brain needs the extra oxygen. The yellow masks will provide you with enough O2 to avoid brain injury. If a loss of pressurization occurs, the pilots will descend the aircraft very quickly (it’ll get your attention) to a safe altitude where the masks are no longer needed. Keep the mask on until the crew tells you to take it off.
If you’ve never seen the oxygen masks drop, take a look at this short video. It was shot during a test flight of a brand new Embraer E170 regional jet. The cabin pressure was intentionally raised to about 14,000 feet to make sure the masks work properly.
Flight crew oxygen masks
Those yellow masks sound pretty good! Why not let the pilots wear them in an emergency? There are a few good reasons why we need special oxygen equipment up front.
Earlier, I mentioned that the yellow passenger masks provide enough oxygen to avoid brain injury. At really high altitudes, the yellow masks start to lose their effectiveness. They will keep your brain safe, but until the aircraft descends into heavier air, you may lose some of your ability to think clearly. As you might imagine, it’s important that pilots can continue to perform complex tasks. Our masks are designed to provide pure, pressure fed oxygen directly into our lungs. These masks will provide pilots with adequate oxygen at any altitude in an unpressurized aircraft. They are called “quick-donning” because we can grab and secure them on our face within 3 or 4 seconds. Once our masks are on, we can quickly descend the airplane to a safer altitude with breathable air.
Smoke is a serious concern for pilots. Occasionally, you may hear about an airliner making an emergency landing because of smoke on the flight deck. Our front office is crammed full of electronic equipment and special lighting. Every once in a while something malfunctions and gets a little too hot, producing smoke. The mask protects our eyes from the smoke so we can get the aircraft safely to an airport.
Our fancy masks are equipped with a built-in microphone. The mic allows us to communicate with air traffic controllers and with each other via the cockpit intercom. Effective communication is critical during an emergency.
Pilots wear oxygen masks quite a bit!
Unlike the yellow passenger masks, flight crew masks get used more than you might think. We test them carefully before every flight. There are also times during a normal flight that we are required to wear them as a precaution. During cruise, when one of the pilots leaves the cockpit (bathroom break!) the other pilot must wear the oxygen mask. We do this in case of an emergency. With only one pilot at the controls, he or she will be really busy should an emergency occur while the other guy is “taking care of business.” Having the mask already on saves precious seconds should something go wrong.
Even at a comfortable cabin altitude of 5,000 feet, the brain isn’t getting as much oxygen as usual (unless you’re from Denver!). One of the problems that occurs at this altitude is the degradation of night vision. During preparations for a night-time approach and landing, pilots will often grab the mask and breathe 100% oxygen for a few minutes. It gives our brains and eyes a little pre-landing oxygen boost. The difference is noticeable. After only a few breaths, colors become more vivid; lights and stars become brighter.
Don’t take the yellow dixie cups masks for granted; they really work. If you see them drop, put your mask on quickly. And rest assured, if your oxygen masks drop down, the pilots up front already have their masks on and are working hard to fix the problem and keep you safe!
Ever wonder how an aircraft pressurization system works? Check out:
Aircraft Pressurization – A Beginner’s Guide