"We believe fundamentally that with proper maintenance and proper inspection an airplane can in fact last forever." Boeing Chairman Frank Shrontz could have been speaking for the entire airline industry when he delivered that traditional wisdom to a gathering of aviation experts in Washington last month. But just two days later, a cargo door and part of the skin tore away from a 19-year-old Boeing 747 shortly after it left Hawaii, sucking nine passengers from the plane. Investigators have not yet officially determined the cause of the failure, but they have focused on the possibility of a faulty door lock.
The...