The plane is when the high flight of 4268 meters of above, want pair of cockpit pressure boost. If in case plane cockpit is broken pressure, can cause anoxic, the passenger will be giddy because of this lose consciousness even, until crisis life. Below the situation that produces cockpit give away official secrets on different height, person can susceptive is anoxic time is 6100 meters 10 minutes respectively, 7800 meters 2 minutes, 9140 meters of 30 seconds, 10700 meters of 20 seconds, 12200 meters of 15 seconds, 19800 meters of 12 seconds. Aerobic face guard is the lash-up lifesaving unit that offers oxygen for the passenger. Below the situation that produces give away official secrets in plane cockpit, the cover meets oxygen carry condole on the head automatically to fall down from cabin, the passenger should take aerobic cover, till the plane drops,pick it to the ability when the safe height that can breathe is the following. Enough aerobic face guard prepared on every airliner, , namely every passenger has deploy, and every pew still deserves to install a pair to reserve more face guard, in case beyond.