Despite the subzero temperatures and lack of oxygen, people can survive even a long journey in the wheel well of a jetliner. While the number of known stowaway attempts is few, people have survived with surprising frequency.
How dangerous are the conditions? Very. At 38,000 feet — the cruising altitude of the Hawaiian Airlines flight that the FBI says the 15-year-old took Sunday — the outside air temperature is about minus 85 degrees. A person will pass out because the brain is starved of oxygen.
The plane’s own machinery can aid a stowaway’s survival, at least initially. Warmth radiating from the wheels, which heat up on the runway during takeoff, and from hydraulic fluid lines can moderate the temperature. But those effects dissipate, and at cruising altitude the temperature in the wheel well would be about minus 30 degrees, estimated John Hansman, a professor of aeronautics and astronautics at the Massachusetts Institute of Technology.
Unlike areas of the cargo hold that are pressurized so that pets can breathe, air in the wheel wells is essentially the same as outside the plane.
And then there is the huge risk when the wheels are lowered for landing. This opens the equivalent of a trap door, turning a cramped but relatively sheltered space into one from which it would be easy to fall thousands of feet to the ground or water below.