Watch Mayday Season 4 Episode 10 Online

On 14 August 2005, air traffic controllers lose radio contact with Helios Airways Flight 522. Two fighters from the Hellenic Air Force intercept and investigate the flight and find all but one person on board not moving. A few moments later, the aircraft runs out of fuel and crashes, killing all 121 people on board. An incorrect setting on the cabin pressurization panel caused the pilots and everyone else on board to succumb to hypoxia.