– Defense Technology International – What’s been reported elsewhere is that investigators have focused on pilot hypoxia (lack of oxygen) as the primary cause for the November 16 crash of an F-22 operating from Joint Base Elmendorf-Richardson in Alaska, and in particular on the functioning of the onboard oxygen generating system (Obogs). What hasn’t been reported is that there is a history of Obogs-related hypoxia issues in the world’s biggest fleet of Obogs-equipped fighters, the bulk of the US Navy Hornet and Super Hornets.