Page 140 - PPL-engelsk 2025
P. 140
Human Performance
2.3.4 Oxygen deficiency
An attentive reader might wonder how stories of oxygen deficiency, which
sound quite alarming, fit with the fact that there is 21% oxygen throughout the
atmosphere.
2.3.4.1 Oxygen absorption at altitude
To understand this, you need to know how oxygen is absorbed.
The inner part of your lungs is filled with tiny sacs that are so thin they allow
oxygen to be pushed through the thin tissue. This process requires pressure.
The partial pressure of oxygen must be at a certain level for us to survive.
You can observe the pressure change in the figure below.
For example, if you are flying at 18,000 feet, the pressure is only half of that at
sea level, and at this altitude, you must add oxygen to the air.
Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 140
