unconsciousness. If you are above 10,000 feet you will die in a short amount of time...............
The Effects of Hypoxia at Various Altitudes
Learjet in flight
Hypoxia is an insidious and progressive condition and is almost undetectable by the pilot. You should always be aware that without supplemental oxygen at sufficient pressure you will gradually and progressively lapse into incompetence while maintaining an absolutely euphoric faith in your own ability.
As blood saturation of oxygen drops there is a steady disruption of life functions. From a blood saturation of 93%, considered the low limit of normal functioning, where visual problems begin to occur, there is a rapid deterioration into unconsciousness with decreasing saturation.
Keep in mind, as mentioned earlier, that although the partial pressure of oxygen in the atmosphere decreases somewhat less than linearly with increasing altitude, the hemoglobin's ability to combine with this oxygen follows a much different and more deadly curve. This property of hemoglobin bears heavily on oxygen requirements at altitude. Let's look at some common hypoxic effects an average, healthy individual can expect with increasing altitudes.
5000 feet. This is considered by most to be a "low" altitude. The retina of the eye is more demanding of oxygen than any other organ of the body -- even the brain itself which demands 30% of the supply. At this "low" altitude this extension of the brain will begin to suffer degradations in function which will be most noticeable at this point in night vision.
Instruments and maps are more easily misread during night flight at this altitude and ground features and lights are more easily misinterpreted. It is always an eye-opening shock to my students when I bring them in over the Mojave Desert after a long flight at a cabin altitude of 8000 feet. After having them note the discernible features on the dark desert floor, I have them breath 100% oxygen for a few minutes. Without exception, all are shocked and amazed to note the features that "jump" out of the blackness after a little O2. Most have heard of this little demonstration before it actually takes place, but none are totally prepared for its dramatic effect. This level of hypoxia is extremely insidious because most pilots feel they are functioning at peak efficiency at this point. Extra vigilance is necessary to prevent missing critical fixes on charts or misreading instruments.
10,000 feet. Night vision is now degraded by 15-25 percent. The blood saturation has dropped to 90 percent and your brain is receiving the absolute minimum supply of oxygen. This is the absolute highest altitude at which you should have any trust at all in your own performance although your judgment is already severely compromised. Euphoria will prevent true self-assessment of your abilities. Physical hypoxic symptoms such as tingling and headache may not become apparent for four hours or more at this altitude, although judgment has long gone by the wayside. Above 10,000 feet blood oxygen saturation and performance degrade steeply.
14,000 feet. Blood oxygen saturation is down to a dangerous 85%. You will be increasingly disabled at this altitude. Vision will dim. You will experience serious degradation of judgment, memory and thought. The impairment of judgment will leave you feeling just fine and confident in your performance, however. If hypoxia is not recognized and corrected at this stage of impairment, it is unlikely that it will be recognized. You are in serious danger.
16,000 feet. Only 2,000 feet higher than the last assessment, but you will behave as though you had ingested a full load of gin and tonics. Your blood oxygen saturation will have dropped to 79 percent and you will be seriously disabled. You will be euphoric, belligerent, disoriented or perhaps all three. You will be irrational, unreliable and dangerous. If you are alone, your chances of survival are decreasing rapidly.
18,000 feet. At this altitude you are incapable of any useful function although you may still feel great! Blood saturation has fallen to 71 percent and your brain is suffering. You will pass out in about 30 minutes.
20,000 feet. If you have not already collapsed, it will not be long now. Five to 15 minutes is about the time of useful consciousness at this altitude and prolonged exposure can result in death. Blood saturation has dropped to 71%.
25,000 feet. Forget it! Blood saturation has now dropped to lethal levels. Time of useful consciousness is three to six minutes with death following not long after that. Above this altitude, suffering a rapid decompression may also result in a condition divers know as the bends and various other pressure related maladies. Remember, this is only HALF as higat altittudeh as some modern civilian aircraft are certified to fly!
But note she was being sucked out by the depressurization of the aircraft, which is 14.7 pounds per square each altitude, which is what the pressure is at sea level
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