Analysis shows Boeing 737 cockpit alarm often ignored by pilots

An "analysis of NASA's Aviation Safety Reporting System (ASRS) has revealed that pilots flying Boeing 737s, the world's most widely deployed passenger aircraft, have frequently been ignoring an onboard alarm horn designed to warn of a critical loss of pressure, and thus a lack of oxygen, in the cockpit," reports Michael Fabey for Travel Weekly.  The 2005 crash of Helios Airway Flight 522, in which all 121 passengers and crew were killed,  was caused by hypoxia.