The first sign something was off was when the ground crew at Kahului Airport in Maui noticed a boy wandering the tarmac, dazed and confused.
The story he told officials was even more incredible.
The 16-year-old apparently hitched a ride from San Jose, California, to Maui, Hawaii, in the landing-gear wheel well of a Boeing 767, Hawaiian Airlines said Sunday.
"Our primary concern now is for the well-being of the boy, who is exceptionally lucky to have survived," the airline said.
He certainly is.
If his story pans out - and the FBI has been called in to investigate - he rode in the tiny cramped compartment for almost five hours, at altitudes that reached 38,000 feet, without oxygen and under subzero temperatures.
That has some experts questioning his story.
"It sounds really incredible," said aviation expert Jeff Wise. "Being in a wheel well is like all of a sudden being on top of Mount Everest."
Between the oxygen depletion and the cold, life expectancy "is measured in minutes," Wise said.
But some people have survived. A total of 105 people are known to have attempted to fly inside wheel wells on 94 flights, the FAA's Civil Aerospace Medical Institute says. Of those, 25 made it through, including a 9-year-old child - a survival rate of 24%. One of the flights went as high as 39,000 feet.
The conditions can put stowaways in a virtual "hibernative" state, the FAA says.
Someone could slip into unconsciousness so that the body cools and "the central nervous system is preserved," said CNN aviation expert Michael Kay. Also, he said, "there could be a situation where inside the bay is warmer than the external air temperature and you wouldn't get the instantaneous freezing of the skin."
Still, "for somebody to survive multiple hours with that lack of oxygen and that cold is just miraculous," airline analyst Peter Forman toldCNN affiliate KHON in Honolulu.
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