A 16-year-old survived a flight from California to Hawaii, hiding in the wheel well. What happens to the human body under those conditions, asks Tara McKelvey.
Ninety-six people are known to have hidden under planes during flights around the world between 1947 and 2012, according to the Civil Aerospace Medical Institute in the US, and 23 survived.
During this five-hour flight across the Pacific Ocean, at an altitude of 11,600m (38,000ft), the teenager reportedly lost consciousness - unsurprising given the lack of oxygen supplied to the brain. "You'd get shortness of breath and then you'd just kind of doze off," says Peter Hackett, director of the Institute for Altitude Medicine in Telluride, Colorado. "It wouldn't be uncomfortable."
Another problem for plane stowaways is the extreme cold - as low as -62C (-80F). "In a cold state, the heart isn't pumping as much blood," says Hackett. "And what blood there is goes to the brain." At a certain point, individuals fall into a "poikilothermic condition", according to authors of a 1996 report for the US Federal Aviation Administration (FAA). This is similar to hibernation, when the body needs less oxygen than normal. The heart rate and breathing slow down dramatically.
Stowaways may also suffer from decompression sickness, caused by an abrupt drop in surrounding pressure. Gas bubbles form in tissues and blood vessels and slow down the flow of blood.
Young people are more likely to survive. The authors of the FAA report said a "youthful, thin" individual has a better chance of enduring this than someone who is "heavy-set and older".
In 2000, a man survived a seven-hour flight from French Polynesia to Los Angeles, "spattered with oil from the landing gear and with his clothes ripped to shreds", according to the Los Angeles Times. And last year, a teenage boy endured a short flight in a wheel well in Nigeria. Others have died when the landing gear is lowered.
"I would not have predicted survival," says Michael Yaron, a professor of emergency medicine at University of Colorado at Denver, when asked about the boy in Hawaii. "Miracles happen. Lucky kid."