At 41,000 feet, the air pressure is too low to oxygenate the blood and keep the brain functioning. So the KAO is equipped with pressurized oxygen (green cylinders) in case of a cabin decompression. Even with the cabin pressurized, however, flying around at 41,000 feet at 3:00 a.m. can make most brains sluggish. Breathing some pure oxygen for a few minutes can put the edge back in your critical thinking when it is most needed.
