On 14 August 2005 , Helios Airways Flight 522 crashed near Grammatiko , Greece , after the crew was incapacitated due to lack of oxygen . All 121 passengers and crew were killed . The investigation concluded that both maintenance crews and the pilots had failed to ensure the pressurization system was set to " automatic " , and as a result , the plane never pressurized . The accident revealed many problems with safety of the airline and led to manslaughter charges against five airline officials
Helios Airways Flight 522
Helios Airways Flight 522
Helios Airways