According to the Air Force , once Mantell passed 25,000 feet ( 7,600 m ) he blacked out from the lack of oxygen ( hypoxia ) , and his plane began spiraling back towards the ground .
Mantell continued to climb , however .
According to the Air Force , once Mantell passed 25,000 feet ( 7,600 m ) Mantell blacked out from the lack of oxygen ( hypoxia ) , and Mantell 's plane began spiraling back towards the ground .
Mantell continued to climb , however .