Originally Posted by Airhoss

Uhmmm,

NO! You do what needs to be done to save your life and the lives of your passenger THEN and only THEN do you advise ATC of what you are doing and declare an emergency. It is spelled out very concisely in the FARs. I've lost a cabin at altitude in an A-320at FL320. YOU DO NOT wait for an ATC clearance YOU DO NOT declare an emergency yet, you put on your mask, you start your rapid descent THEN and only then do you advise ATC that you are doing an rapid D and declare an emergency.