Oxygen O 2 is the most vital of the gases that comprise our atmosphere. The typical percent of oxygen in breathable air is More on that in a moment. For purposes of this article, all altitudes will be given above sea level.
The cruise portion of most airline flights take place between 30, and 40, feet. Because the time of useful consciousness for a human at those altitudes is just moments, the passengers and crew need a way to get sufficient oxygen pressure.
In airliners, providing sufficient oxygen pressure for crew and passengers is done by pressurizing the entire compartments occupied by humans, often to about 6, feet, where the is plenty of oxygen pressure for normal operations.
If an airliner in cruise loses pressurization, the captain must dive the airplane down as fast as possible without hurting the structure of the airplane to get to an altitude where there is higher natural oxygen pressure. This is the situation where airlines are actually providing oxygen for passengers. Small, non-pressurized airplanes rarely go into those high altitudes, but they can get close.
As a result, the FAA Federal Aviation Administration has created regulations for the use of what is called supplemental oxygen. Supplemental oxygen for passengers in small airplanes may be built-in, but, in most cases, is brought on board as a separate oxygen system that can be removed when the flight is over.
That system will contain an oxygen cylinder, a regulator, tubing, and a way to get the gas into the body. The supplemental oxygen systems provide oxygen to the body usually through nasal cannulas. You may have seen these in hospitals, where patients have small tubes inserted up both nostrils, and the tubes are providing pure oxygen.
There are other systems, but the norm for a supplemental oxygen system is the dual-cannula method of delivery. Of course, if the flight is not expected to get close to the altitude where supplemental oxygen for passengers is required by regulation, there is no need to bring that system on board.
Below, we will only consider the most typical kinds of small airplanes. At the end of this article, you will learn a fun bit of trivia about pressurized versus non-pressurized small planes. It is interesting that the FAA rules differ for flight crew pilot, and if necessary, first officer or co-pilot and passengers.
Of course, it makes sense that pilots absolutely must have the optimal amount of oxygen during all flight time where oxygen for passengers might be scarce. When the altitude of an airplane is less than 12, feet, there is no supplemental oxygen required for anyone in a private plane. From 12, feet to 14, feet, supplemental oxygen must be used by the required flight crew for any portion of the flight that is more than 30 minutes.
So a brief excursion upward to, say, 13, feet, with a return to below 12, feet within 15 minutes or so, is completely legal and does not require supplemental oxygen. But as soon as those 30 minutes are up, the required flight crew must be using supplemental oxygen. Notice that, at this point, there is no requirement to provide any supplemental oxygen for passengers.
Between 14, feet and 15, feet, all required flight crew members must be using oxygen all the time. Also, oxygen for passengers must be available. If you regularly fly at altitudes above , feet, you should invest in a pulse oximeter. These relatively inexpensive devices clip onto a fingertip and read out blood oxygen levels.
Hypoxia is a state of oxygen deficiency in the body sufficient to impair functions of the brain and other organs. Symptoms include headache, dizziness, confusion, shortness of breath, restlessness, changes in skin color. My comments appear in green. The easiest way to comply is to don oxygen when one pilot leaves the controls and to flight plan below FL When weather or winds dictate a climb above FL , pilots should trade off oxygen mask duties every 30 minutes.
I know, most of you are saying this is nuts. You might be right, read on. This includes the amount of oxygen, the types of masks, and how long you can take descending. But nary a word about using oxygen under normal conditions.
A flight to be operated at flight altitudes at which the atmospheric pressure in personnel compartments will be less than hPa shall not be commenced unless sufficient stored breathing oxygen is carried to supply:. A flight to be operated with a pressurized aeroplane shall not be commenced unless a sufficient quantity of stored breathing oxygen is carried to supply all the crew members and passengers, as is appropriate to the circumstances of the flight being undertaken, in the event of loss of pressurization, for any period that the atmospheric pressure in any compartment occupied by them would be less than hPa.
In addition, when an aeroplane is operated at flight altitudes at which the atmospheric pressure is less than hPa, or which, if operated at flight altitudes at which the atmospheric pressure is more than hPa and cannot descend safely within four minutes to a flight altitude at which the atmospheric pressure is equal to hPa, there shall be no less than a mnute supply for the occupants of the passenger compartment.
All flight crew members, when engaged in performing duties essential to the safe operation of an aeroplane in flight, shall use breathing oxygen continuously whenever the circumstances prevail for which its supply has been required in 3. All flight crew members of pressurized aeroplanes operating above an altitude where the atmospheric pressure is less than hPa shall have available at the flight duty station a quick-donning type of oxygen mask which will readily supply oxygen upon demand.
There is no ICAO requirement to use oxygen under normal circumstances. The altitudes are similar to U. Combing through the NTSB database, you will find many examples of airlines experiencing fuselage metal fatigue resulting in cabin depressurizations. What about jet corporate aircraft? Just one. Why is that? Aircraft in airline service accumulate thousands of pressurization cycles and flight hours, pushing the limits of metal fatigue.
In a typical corporate flight operation you will see only a fraction of cycles and hours. There are studies claiming ill effects of breathing pure oxygen over time.
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