Oxygen Masks - P2
An oxygen duration chart is provided in Section 7 of the flight manual for a guide to the system capability depending on the size of the oxygen cylinder and the number of occupants in the aircraft.
It is important that this chart be understood should its use be required during high risk operations.
Refer manual for detailed image..
CAO 20.4 section 7 states that supplemental oxygen is to be provided to the operating crew for:
- a minimum of 15 minutes for all times that the aircraft is operated above 10 000', and
- Be used by the operating crew during all periods that the cabin altitude is in excess of 10 000'.
For passengers, CAO 20.4 section 7 states that supplemental oxygen is to be provided to:
- 10% of the passengers for a minimum of 30 minutes, or 20% of the passengers for 15 minutes for an aircraft able to descend to FL140 within 4 minutes,or
- To provide each passenger with oxygen for so much of the flight time that exceeds 4 minutes, plus 10% of the passengers for a minimum of 30 minutes, or 20% of the passengers for 15 minutes for an aircraft unable to descend to FL140 within 4 minutes.
Another useful chart is the Time of Useful Consciousness chart which is provided below. This chart is only an average as individuals will react differently to the effects of Hypoxia.
Time of Useful Consciousness