Originally Posted by
mustafagander
.... or a fairly big hole (QF30) you would have the worst survivable case IMHO. The cabin alt will NOT immediately be at outside alt, nothing like it. You will meet the cabin on the way down according to reports from those who have "been there and done that". Much greater structural damage and it becomes academic interest only, you're screwed and the aircraft is unflyable. If you have a total failure of the air ducts into the packs somehow, the cabin climbs quite slowly.
Well, having been there and done that...the cabin reached cruising altitude well before the descent was even started. The RoC was in excess of 100,000 fpm.
In reality you have more than enough time to get your sweep on mask properly fitted and commence descent without rushing things. A turning entry is to be recommended because you really don't want meal or bar carts floating around so about 25* AoB will give a little positive G to keep the carts on the floor, initiate the descent gently as the nose drops - on Boeings anyway - and get you off the airway. Don't forget to turn back parallel around five miles offset. Unless you are ABSOLUTELY certain that there is no structural damage, do not increase speed. It is reported that Boeing stated that had QF30 sped up much it would have been likely catastrophic. Also be sure that the A/P is responding correctly - the electrical wires were broken on QF30.
All great plans...but if the cabin climbs that fast you most certainly have a lot of damage. Just holding it wings level may well become the best idea. The cockpit will be going mad with warnings. The most important one of all might not even be that obvious. Believe it or not, the physiological effects might not be as obvious as you expect.
The QF30 A/P disconnected initially because the starboard aileron cables were cut. The others wouldn't engage because one of the ADCs had failed.
As for the OPs initial comment...I wouldn't stay at altitude for one second longer than needed. Mad.