Officials today were investigating the death of a teenager from South Africa whose body was found on Sunday in the wheel well of a British Airways jet at Los Angeles International Airport.A British Airways pilot found the body during a routine preflight check on Sunday about 4:30 p.m. It arrived at LAX from London Heathrow Airport at 3:15 p.m. and was to depart for a return flight at 5:20 p.m. on SundayThe 747-400 flight originated in Cape Town, then went to Singapore and Hong Kong before going to Heathrow.Authorities today did not formally identify the victim. A source familiar with the investigation said the youth — believed to be 17 or 18 — carried documents identifying himself as a South African national born in 1989.“The investigation needs to run its course to determine where and how the victim obtained access to the aircraft before it landed at LAX on Sunday afternoon,” Paul A. Haney, deputy executive director of airports and security for Los Angeles World Airports, said on Sunday.There have been several incidents in recent years of people climbing into airplane wheel wells — usually ending in death, authorities said.A body was found January 12 in a plane that landed in Atlanta. The man, who carried no identification, was believed to have entered the compartment when the plane left Dakar, Senegal, for the nine-hour flight to Atlanta.Extreme cold and a lack of oxygen in the wheel wells make the odds of survival slim. Stowaways also have fallen from the wheel wells or been crushed by the landing gear.But there have been a few cases of stowaways surviving.In 2000, a man survived a flight from Papeete, French Polynesia, to Los Angeles. His core body temperature when he was found at LAX was 79 degrees, well below what is normally fatal. A Cuban man made it alive to Montreal in the wheel well of a plane in 2002. And in 1999, an 18-year-old Senegalese man survived a five-hour flight to France, but died after he stowed away on another flight later that year.More typical are cases like Sunday’s discovery of the body at LAX. Authorities are uncertain, however, of the survival rate of wheel-well stowaways, because bodies that fall out of flying aircraft may not be recovered. Stowaways unable to secure themselves can fall more than 1,000 feet when landing gear doors open. Experts believe that many of those who fall out are already dead or unconscious.