

Three planes fatally out of balance force investigators to question every calculation; it's a flight risk that's entirely preventable, and yet repeated disasters reconfirm the need for critical backup systems.

During a storm, a strong gale slams Delta Air Lines Flight 191 to the ground, killing most people on board.

A freight train carrying an excess of cargo loses its brakes while descending a mountain causing it to gain speed and derail into a neighborhood killing several people.

After touching down, a Taiwanese commuter plane is rocked by a massive explosion, but investigators find no evidence of a bomb on board.

A helicopter carrying offshore drilling workers crashes into the ocean, leading to an investigation that reveals a fatal flaw in the chopper's design.

A cleaning crew makes a careless error while cleaning a Boeing 757, affecting the plane's computer system and causing it to crash into the Pacific Ocean.

When a DC-8 cargo jet crashes on approach to a U.S. naval base in Guantánamo, investigators wonder if Cuba played a role.

Facing a cascade of failures and a fire on board, a turboprop is just seconds from landing when it flips over and crashes.