Somewhere between 30,000 and 40,000 feet the pressure around you becomes far too low to push those oxygen molecules across the membranes in your lungs, and you get hypoxic (altitude sickness). If you try to breathe 100 percent oxygen above 40,000 feet for very long without a special type of mask, you'll die.
Mount Everest, the highest summit in the world, has around 67% less oxygen than sea level! That's why so many people need additional oxygen as they summit Everest. Past 30,000 feet, there is simply not enough oxygen for humans to survive.
- It would be virtually impossible to survive ejection from an airplane at 30,000 feet. - A rapid drop in oxygen and extraordinarily cold conditions would be just two of the deadliest consequences. - People have been sucked through holes in airplanes before, but skilled pilots can often save the day.
At 25,000 feet the average EPT is 3 to 5 minutes. After about 20 minutes without supplemental oxygen, you will be pronounced dead.
It is the lack of oxygen rather than the reduced air pressure that actually limits the height at which we can breathe. An elevation of about 20,000 feet above sea level is the maximum height at which sufficient oxygen exists in the air to sustain us.
Somewhere between 30,000 and 40,000 feet the pressure around you becomes far too low to push those oxygen molecules across the membranes in your lungs, and you get hypoxic (altitude sickness). If you try to breathe 100 percent oxygen above 40,000 feet for very long without a special type of mask, you'll die.
For operations conducted under Parts 121 and 135, the flight crew must use oxygen when cabin altitudes are above 10,000 up to 12,000 feet after 30 minutes and at all times when above 12,000 feet. The general aviation pilot flying an unpressurized airplane will not normally operate above 25,000 feet.
And that at cabin altitudes above 14,000 feet pilots must use oxygen at all times. And that above 15,000 feet each occupant of the aircraft must be provided supplemental oxygen. All of this is spelled out in Federal Aviation Regulations Part 91.211.
In an unpressurized cockpit at altitudes greater than 11,900 m (39,000 ft) above sea level, the physiological reaction, even when breathing pure oxygen, is hypoxia—inadequate oxygen level causing confusion and eventual loss of consciousness.
Between 9,000 and 12,000 metres (30,000 and 40,000 feet), the cruising altitude of most jet aircraft, air temperatures range from −40 to −70 °F (−40 to −57 °C).
Above about 8,000 meters (26,000 feet), the human body cannot survive at all, and starts to shut down. Mountaineers call this altitude the "death zone." To prevent severe altitude sickness, mountaineers bring supplemental (extra) supplies of oxygen and limit their time in the "death zone."
Above 40 000 feet, positive pressure breathing with 100% oxygen is required. Without positive pressure breathing, even very short exposure to altitudes greater than 43 000 feet leads rapidly to unconsciousness. Aircraft cabin pressurisation systems were developed mainly to prevent hypoxia.
But generally, most commercial passenger jets cruise at between 32,000 and 40,000 feet—or six to seven-and-a-half miles off the ground. Turboprop planes, which are smaller aircraft that typically carry a handful of passengers, rather than hundreds, fly at a lower altitude of about 25,000 to 30,000 feet.
Many business jets can travel even higher, at 50,000 feet, due to having large engines for the small size of the aircraft. The lighter weight enables these aircraft to climb higher more easily than larger jets with many passengers and materials.
Most commercial aircraft are pressurized to 6,000 to 8,000 feet, not sea level. "In order to pressurize at ground level, we would have to increase the weight of the aircraft tremendously, because the material as it exists right now couldn't tolerate pressure at ground level," explained Dr.
The freefall time from extremely high altitude jumps like the 30,000 ft HALO jump mentioned above is around 170 seconds or 2.5 minutes. A more typical, although still fairly rare, high-altitude skydive from 18,000 feet has a freefall time of 80 seconds or 1 minute and 20 seconds.
In typical HALO/HAHO insertions the troops jump from altitudes between 15,000 and 35,000 feet (4,600 and 10,700 m). Military parachutists will often reach a terminal velocity of 126 mph (203 km/h), allowing for a jump time under two minutes.
Taking a Fall: The 120-MPH, 35,000 Feet, 3-Minutes-To-Impact Survival Guide. You're six miles up, alone and falling without a parachute. Though the odds are long, a small number of people have found themselves in similar situations—and lived to tell the tale.
When you go to a high elevation there is less air pressure. The lower air pressure makes air less dense (thinner) and so there is less oxygen in the air you breathe. At the top of Mount Everest there is only ⅓ of the oxygen available as there is at sea level.
Most of the time, though, decompression is survivable. One Southwest Airlines flight got a 17-inch hole in the fuselage while flying at 34,000 feet and absolutely no one died.
Pulmonary effects can present as early as within 24 hours of breathing pure oxygen. Symptoms include pleuritic chest pain, substernal heaviness, coughing, and dyspnea secondary to tracheobronchitis and absorptive atelectasis which can lead to pulmonary edema.