At the first indication of a pressurisation problem or symptoms of Hypoxia, all crew members should immediately don oxygen masks. At cruising altitudes and without supplemental oxygen, the Time of Useful Consciousness can be less than one minute in the event of an explosive decompression. Once the mask is donned and the crew members are protected against hypoxia, flight duties can be resumed.

Note: Operators should stress in their procedures, initial and recurrent emergency training, that the first and immediate action for all crewmembers during decompression is to immediately don the nearest oxygen mask