Authorities are still investigating the case, but a 16-year old stumbled out of a Hawaiian Airlines flight from San Jose, Calif., to Maui on Sunday, after apparently hitching a ride in the wheel well of a Boeing 767. Officials say he was unconscious during most of the five-and-a-half-hour flight, and is lucky to have survived.
The plane reached an altitude of 38,000 feet, at which point oxygen is scarce and the brain shuts down, say experts. Without enough oxygen to keep brain cells functioning, people at high altitudes first develop lightheadedness, and, if they don’t receive oxygen, lose consciousness in a matter of minutes.
Here’s what the teen faced, and experts’ best guesses as to how he survived:
Lack of oxygen
Without oxygen, nerve cells in the brain start to falter, resulting in dizziness, nausea, shortness of breath, and loss of appetite and energy. Because the brain regulates much of the body's metabolism, a de-oxygenated brain can lead to other organ failure as well. Fluid can build up in the lungs and brain and lead to potentially fatal swelling.
In this case, the teen’s youth could have been an advantage. “The brains of young people are more adaptable, and recoveries of kids who were comatose for a long period of time are more likely than recoveries among older patients,” says Dr. Ben Honigman, medical director of the Altitude Medicine Center at the University of Colorado.
Researchers are also finding that some genes that can predict who suffers from altitude-related sickness. That may explain why certain people experience more symptoms in mountain regions, while others, perhaps such as this teen, could pass out but regain consciousness when back at sea level.
There may be psychological contributors as well. According to a Federal Aviation Administration (FAA) report [PDF] of 10 such cases involving 11 wheel well stowaways, five survived flights that reached as high as 39,000 feet. Many were politically motivated to escape, which FAA officials believe may have contributed to their ability to reach a “virtual ‘hibernative’ state” in order to survive. In a more recent study by researchers at the FAA and Wright State University, two passengers survived flights at 35,000 feet – one from Havana to Madrid and another from Bogota to Miami. The scientists speculate that the gradual climb of the plane allowed the stowaways to acclimate somewhat to the changing air pressure and low oxygen conditions, although Honigman notes that such acclimation occurs over just 10 to 20 minutes, while most mountain climbers take days or even weeks to acclimate to altitudes higher than 20,000 feet.
At plane-flight altitudes, temperatures can drop to 80 degrees below freezing, another way stowaways can die. But according to the Wright State study, some heat from the hydraulic lines powering the wheels and residual heat from the tires can warm up the well slightly, and that same source of heat during descent may help some stowaways regain consciousness. “I have to think that the temperature in the wheel well wasn’t around minus 40 degrees,” says Honigman. “I can’t conceive that he could have survived those temperatures for five hours; he would have been frost bitten or turned into an icicle.”
Even if it were that cold, there is a remote chance that the cold may have helped the teen survive the journey. Some research on survivors of near-drownings in lakes suggests that extremely cold temperatures and a lack of oxygen may put the body into a hibernation state as the heart rate slows and the body’s metabolism drops to minimal levels. But those experiences generally last only a few minutes, not the five hours that the teen endured on his oceanic flight.
If the boy’s story is confirmed, he joins a small group of flight stowaways who found some way to survive on low oxygen, low temperatures, and low air pressure under conditions that weren’t meant for human beings. “He’s a really lucky boy,” says Honigman.