A dead body was found in the wheel well of a United Airlines jetliner after the aircraft landed in the Hawaiian island of Maui, the airline said on Wednesday (Dec 25). The body was discovered in the one of the compartments that houses the airplane's landing gear when United Flight 202 from Chicago O'Hare I
Stowaways often get in there. It doesn’t typically end well for them. That area is not pressurised or heated.
https://en.m.wikipedia.org/wiki/Wheel-well_stowaway