Hello Mahdi,
In a past life in an A320 the number one engine bleed tripped off just after take-off. No problem here as we are legal to dispatch with just one. ECAM followed but it did not reset.
During the climb the First Officer had the MEL out to see if there were any limitations we may want to consider when on comes the Master Warning and the ECAM says Engine Two Bleed Fault.
So, now we have the same situation a Dual Pack Fault. No air coming in and air still going out.
The first thing that happens is the outflow valves close to help limit the air loss. The second thing that happens is that the pilots look in stunned silence at the ECAM for a second or two, realize what the situation is, put on their O2 masks, declare an emergency and start downhill.
This happened at 21000 in the climb. We completed the applicable parts of the Emergency Descent Drill and then when all was under control headed for the QRH to see what we might do about getting a bleed or two back.
The cabin altitude climbed about 700 fpm and it never got higher than about 7000 feet.
By the time we got to resetting the bleeds they had both reset on their own As it was, one had tripped off for over pressure and one had tripped off for over temperature. Both had come back within limits during the descent.
best regards,
Bruce Waddington