I have looked it up to make sure.
The ATR oxy system has been designed to supply 3 cockpit crew and 10% of the passengers during: 4 minutes for descent 25000 to 14000 feet; continuation of flight between 14000 and 10000 feet for 26 minutes.
One oxygen bottle with one regulator and one shutoff supplies flight deck masks and numerous ports in the cabin. The cabin supply can be isolated with a further shutoff to prioritise supply to the flight deck.
Therefore there is the same duration of supply to both compartments.
There is no oxygen generation system.
Cabin crew have portable bottles for independent supply.
Last edited by avoman; 11th Sep 2003 at 15:27.