A teenager who stowed away on a flight from San Jose to Hawaii and survived did not know where the plane was headed when he climbed aboard, FBI officials said on Monday.
The 16-year-old, who has not yet been charged with a crime, had run away from home when he climbed a fence at San Jose's Mineta International Airport on Sunday morning and crawled into the left rear wheel well of Hawaiian Airlines Flight 45.
"He was not planning on going to Hawaii," said FBI Honolulu spokesman Tom Simon. "He just got on a plane."
Authorities called it a "miracle" that the teen survived the five-hour flight. The wheel well of the Boeing 767 is not pressurised or heated, meaning the teen possibly endured extremely thin air and temperatures as low as 62 degrees below zero Celsius when it cruised at 38,000 feet (11,580 metres).
"How he survived, I don't know," Mr Simon said. The boy was unconscious for most of the flight, Mr Simon added.
"I imagine he must have blacked out at about 10,000 feet," he said. "The air is pretty thin up there."
According to the Federal Aviation Administration, the plane's steady climb to high altitudes may allow a person to drift into unconsciousness as oxygen becomes scarce. And as the heat dissipates from the wheel well, a stowaway can develop hypothermia, a condition that preserves the central nervous system. Both hypoxia and hypothermia may resolve as the plane gradually descends for landing, the FAA said.
Authorities are still investigating how much of this came into play with the teen who was found on the tarmac at Maui's Kahului Airport.
Authorities say security video shows the teen from Santa Clara hopping a fence at the San Jose airport and climbing into the wheel well of a jetliner.
The plane landed at Maui's Kahului Airport at 10.30am local time on Sunday, but Mr Simon said the teen did not regain consciousness for an additional hour. Once he woke up, he hopped down to the tarmac.
Hawaiian Airlines personnel noticed the teen on a ramp and notified security, airline spokeswoman Alison Croyle said in a statement released on Sunday night.
"Our primary concern now is the wellbeing of the boy, who is exceptionally lucky to have survived," the statement said.
Mr Simon said the teen had run away from home. There was no indication that he posed a threat to the airline, and he has not been charged with a crime, officials said.
He cleared a medical checkup and was handed over to officials from the Hawaii Department of Human Services. Officials did not release his name because he is a minor.
Rosemary Barnes, a spokeswoman at the San Jose airport, said the FBI and Transportation Security Administration were investigating how the teen breached security and made it onto the plane but could provide no further comment.
The teen's case is extreme, but it's not the first time a stowaway has survived a flight in the wheel well of an aircraft.
In August 2013, a teenage boy from Nigeria endured a 35-minute trip in the wheel well of a domestic flight that landed in Lagos. Officials credited the trip's short flight time and relatively low altitude with helping him survive.
On another occasion, a stowaway managed to survive a flight from Havana to Madrid, according to the Federal Aviation Administration.
But in 2012, the body of a 26-year-old stowaway was found crumpled on a suburban London street. Officials believe he had climbed aboard a British Airways plane in Angola and was either dead or near death as he fell from the wheel well during the plane's descent into Heathrow Airport.
Los Angeles Times