“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
Great article Ken. Again! It’s becoming a habit with you.
Thanks, Bruce! Writing keeps me out of trouble on layovers. 🙂
Oh! That’s where I went wrong.
You said@ 35000 fret there is not enough oxygen.if you are using bleed air where does the oxygen come from?
There is plenty of oxygen in the air at 35,000. The problem is the air molecules are really spread out. The pressurization system gathers the thin outside air, compresses it to a pressure that is compatible with human anatomy, and pumps it into the cabin.
Thanks for reading!
Do pilots still wear yellow glasses at night? I remember it’s for better vision.
Interesting question. I have never seen anyone wear yellow glasses at night.
In the 1970ies it was said pilots used them. Now seems different opinions as I found this
I think it was a sales pitch from the late-night infomercial crowd. 🙂
I’ve heard the REAL reason for the yellow dixie-cup masks is to muffle the screams of the passengers so as to not upset the flight attendants.
Hmmm. I’ll have to look into that theory.
Thanks for reading!
I have 2 questions about this, probably stupid but I don’t know and always wondered 🙂
1 – if you are travelling with a small dog, is there enough oxygen for both of you to share? And should you pass the mask from one to the other one or try to make it fit for both (hard)?
2 – Do they have one of those in the restroom? or even in case you are just stretching your legs looking out the door window? What about the crew since they are always walking around?
Interesting questions! Rows of airline seats usually have an extra drop-down mask for children sitting on an adult’s lap, but don’t get any ideas about little Rover using that spare mask! Most airlines require that pets remain locked inside a kennel, and under the seat in front of you for the duration of the flight. In the event of a pressurization emergency, you won’t have time to remove your pet from the kennel (and you shouldn’t try). Trust me, the crew will be descending very fast to get the aircraft to a safe altitude where supplemental oxygen is not necessary for you or your pet. Your dog will be safer staying in the kennel.
Aircraft lavatories are usually equipped with emergency oxygen masks. Flight attendants can always grab an extra mask from one of the rows if they need one. Cabin crew stations also have emergency walk-around oxygen bottles for this purpose.
The bottom line: Pressurization emergencies are really, really, really rare. When I go to work, I am far more worried about what I’m going to eat during cruise than I am a pressurization failure on my jet.
Thanks for reading!
Thanks for answering!
I’m glad to hear that there are plenty of masks to go around, they really planned ahead for anything! 🙂
Noticed you said “usually” though for the lavatories. I’m going to assume that big planes do have them. And by “big” I mean what I call “real” planes with “real” engines. I don’t want a turboprop plane (I think that’s the name). I know they are supposed to be as safe as “real” engines and all but I don’t know…..not for me 🙂
Thanks again! this website is awesome!
Thanks for reading!
In regards to your second question short answer yes long answer I know that the a320 has two masks in every toilet and I believe that this is the same in most aircraft
Hello Ken. Can you p!ease tell me if a pilot after having gone through lobectomy and chemotherapy can fly in an a non pressurized cockpit at an altitude below 1000 feet. I was flying Cessna Caravan till 2014 when I suffered with the above mentioned problem. Now I am much better and cleared by medical examiners for flying.
I’m not a doctor and can’t answer that question. You’ll need to talk with your physician.
Thanks for reading!
good article. crystal clear.
Hi Ken – interesting reading – thanks for sharing. In an explosive decompression incident at 31000 ft would you still have time to don your face mask?
Useful consciousness at 30,000′ is 1-3 minutes; 35,000′ is 30-60 seconds. This is based on the average person, average health. If you’re a smoker, you would fall on the low end. An Ironman athlete is on the high end. It takes about 10-15 seconds to get a quick-donning mask on and adjusted. In emergencies involving smoke or pressurization, the mask is the first thing we grab.
Thanks for reading!
Should the mask cover your nose or just your mouth? Does themask need to fit snugly against your face? That seems to be impossible with the dixie cup shape unless the material is soft enough to conform to your facial features.
The mask should cover the nose and mouth – exactly as demonstrated by flight attendants before every flight. It’s ok if the mask isn’t a perfect fit. As long as it’s covering the nose and mouth, the oxygen will do its job.
Thanks for your article!! Very interesting information to be shared!!
Thanks for fascinating article. 100% O2 is very dangerous cocerning fire risk. Where does this come from? Is the supply the same from the pilots full face mask and the passengers cup?
Flight crew oxygen is supplied from dedicated oxygen bottles. Passenger oxygen masks are usually supplied by chemical oxygen generators that activated when the cup is pulled down from the compartment.
Thanks for reading!
Thanks a lot for the informative and clear article. As a military pilot I had to wear an oxygen mask from Day 1, with a regulator to provide the correct air mix at lower altitudes. Please tell us whether passengers get 100% oxygen from the yellow masks, and for how many minutes the supply lasts, for pilots and passengers.
Passenger masks mix cabin air with the oxygen flowing into the mask. Regulations are different based on aircraft, airline type, and altitudes flown. Most rules require between 10 and 30 minutes of oxygen supply for passengers. The passenger supply provides adequate oxygen while the flight crew descends to an altitude where supplemental oxygen is no longer needed.
Pilots have no less than 2 hours (possibly more due to regulations) of 100% oxygen supply for each crew member.
Thanks for the really interesting article.
My father was a pilot in the second world war and a pilot for Finnair after the war untill the 70’s.
During those years he had a few really close calls, but was lucky to make it.
He told me, that in the modern times pilot error is a bigger cause of accidents than mechanical problems, due to the fact that modern pilots “do not learn to fly by the seat of their pants”, “they do not get the feel of the aircraft”, when something really unusual happens quickly.
Instead, they learn in simulators and that does not teach you about the scare of “the real thing”, so they panic when something happens.
Do you agree?
Pilot error has always been a significant cause of accidents – and it was far worse in the 1970s. The airline industry is enjoying an amazing safety record that is unparalleled in history. Technology and improved aircraft design has reduced mechanical problems. Training and Cockpit Resource Management has reduced pilot error.
Part of the reason for the improved safety is our current training environment. If your father retired in the 1970s, he never had the opportunity to fly a modern simulator. The current generation of simulators faithfully replicate situations that have (or would likely have) ended in tragedy. A good example of this is the 1985 DFW L-1011 wind shear accident. I have flown this profile in the simulator numerous times (and safely recovered). Simulators are now able simulate aircraft response in extreme situations that previously could only be discussed in the classroom – high altitude stalls and upset recovery.
Modern simulators are so realistic, pilots experience sweat, adrenaline rush, increased heart rate, and stress – all in a controlled training environment.
As for “panic” during an emergency… There have been several high-profile airline emergencies in recent months where the flight crews performed admirably. Their professionalism in the cockpit assured a safe outcome.
Can a heart failure patient fly high? Can the oxygen mask be used when it is needed? Should the patient inform the attendance? Thank you.
Anyone with special medical needs or conditions should talk to their doctor before flying. Oxygen on aircraft is provided only for emergencies. Passengers requiring supplemental oxygen while flying need to check with the airline and provide their own.
I require oxygen which I carry with me. On a recent flight I was told that the portable oxygen concentrator should be able to last for 2 1/2 times the length of the flight. Is that because it is more difficult for the concentrator to concentrate oxygen from the cabin at an altitude of 35,000 to 38,000?
I’m not really sure. I suspect it is in case of delays. The inside of the cabin stays between airport altitude and 7000 feet during a typical flight. Please contact the airline and ask your health care provider for more information.