We have all seen the Hollywood movies where the fighter pilot rips off their mask after a heroic dogfight, but in real life would this ever happen? Do they wear masks just to look cool, because airline pilots don’t wear them!
Fighter pilots wear masks to supply them with oxygen to avoid Hypoxia when flying over 10,000 feet. Fighter aircraft have a dynamic pressurization system & when flying at very high altitudes, the pilot will have decreased atmospheric oxygen pressure for breathing. Masks prevent this.
There have been numerous crashes shown on the news where a perfectly healthy pilot has lost consciousness and crashed. Lack of oxygen in the blood is one of the main causes of unconsciousness. The other is High-G loads.
This article is going to cover the oxygen side of why some pilots wear masks and others don’t.
Why Are Aircraft Masks Needed?
The body requires oxygen to function, everyone knows that. The air we breathe is made up of 78% Nitrogen, 21% Oxygen, and 1% of other gasses, so there is 21% Oxygen available everywhere, but yet we still get told in every airline safety briefing that we need to don a mask if they fall from the ceiling – Why?
It is all to do with atmospheric pressure pushing the oxygen molecules through the lining in our lungs and into our blood.
At sea level, we have the weight of all the air above us pushing down on us so this high pressure makes it easy for the oxygen to get pushed into our lungs. As the body climbs in altitude, there are fewer air molecules above us, thus less air pressure to push the oxygen through the lining of our lungs.
The body reaches a point when the atmospheric air pressure is not sufficient to push enough oxygen into our bloodstream and we start to show symptoms of oxygen deprivation – This is Hypoxia.
Once the human body climbs above 10,000 feet above sea level this lack of atmospheric pressure starts to show. The higher the body goes, the faster the onset of Hypoxia happens.
There are two ways to prevent hypoxia:
- Pressurize the aircraft where a person sits to a low altitude pressure
- Supply the person with a mask that supplies oxygen
Lets look at both of these points…
Why Fighter Pilots Wear a Mask?
Most fighter jets have a pressurization system that is dynamic and what this means is that as the aircraft climbs and descends, the pressure inside the cockpit also changes.
A static pressurization system would keep the cockpit/cabin at a set pressure, eg 6000ft, no matter what altitude the aircraft climbs to.
When a fighter jet begins to climb, so does the dynamic pressure inside the cockpit, albeit at a much lower altitude. For example, if the fighter jet was in a cruise at 15,000 feet, the cabin would be pressurized so the pilot would feel like they are at 8,000 ft.
This pressurization scale is not linear so if the jet were to climb to an altitude of 40,000 ft, the cockpit could be pressurized to 18,000ft for example – This would require the pilot to be on oxygen.
Most military’s regulations state that anytime a fighter jet is above 10,000ft the pilot needs to be on oxygen. Because a fighter jet has the power to reach that altitude in seconds the pilots wear their masks from start to finish.
One of the benefits of flying in a military fighter jet is the ejection seat feature. When a pilot ejects from a doomed aircraft the mask automatically switches to an oxygen bottle mounted on the seat to allow the pilot to continue breathing from a high-altitude ejection.
The pilot will remain with the seat as it descends until they are below 15,000ft at which time they release from the seat and its oxygen bottle and are able to breathe atmospheric air for the remainder of the drop. The few minutes under parachute from 15,000ft will not induce Hypoxia as the pilot is decreasing with altitude.
Having clear communications from the pilot to other pilots, air traffic control, or crew members is paramount. Because the pilots have to wear a mask for the flight duration, the manufacturers integrate a microphone into the mask.
Without this integrated microphone, the pilots would have to wear throat microphones strapped to their neck, but the quality of the voice communication is now where near as clear as the in-built microphone of the mask.
Why Airline Pilots Don’t Wear a Mask
I know when I fly I don’t want to wear a mask for the duration of the flight so commercial and private aircraft are pressurized to a static pressure.
Aircraft with a static pressurization system must maintain the cabin/cockpit pressure of 8000ft or under no matter what altitude it flies at. This allows all occupants to not require a mask to be worn, including the flight crew.
Oxygen masks are needed when the aircraft has a depressurization of some kind, whether it be a slow leak or a rapid decompression. This is where oxygen masks drop from the ceiling, as shown in the passenger safety briefing at the start of the flight.
To comply with FAA regulations each seat must have an easily accessible oxygen mask. Flight crews also have easily accessible oxygen masks located by each seat so in the event of them being required, they can be installed easily in seconds.
Check out this awesome video from Destin at Smarter Every Day – It shows EXACTLY why fighter pilots and anyone, in fact, needs to wear a mask once an aircraft’s cabin pressure climbs above 10,000 feet!
No matter if you are in an aircraft or climbing a mountain, anytime you ascend above 10,000ft your body will require oxygen supplementation for you to survive.
The higher you go, the faster Hypoxia will take effect but once oxygen is supplied the body quickly recovers and functions normally. Wearing a mask or being in a statically pressurized aircraft are just some of the ways aircraft manufacturers keep the body safe when we take to the skies!
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