Hola Anthony...
xxx
Sure, there are oxygen masks... but their value to "sustain" life, up there is often exagerated. Pilot masks are ok, they can "do the job" at some FL 250/300, but I would not trust one much above that. Passenger masks... I don't want to say what my opinion is...
xxx
Explosive decompression, get down fast. Do your check-lists if you have the time,
but first get down... ASAP -
Get your mask ON first...
Speed brakes...
Get down on the barber pole...
xxx
We have (in the 747 at least) 2 different emergency descent procedures. One is with the gear up, the other, is first slow down to get the gear down (gear extension speed), then descend. With the first procedure (clean configuration), if started around say FL370, we will be out of the high levels earlier, reaching FL250 or lower, much faster. In the "gear down descent", we will be down to FL140 sooner, but our time to reach say FL250 will be longer... My idea (and preference) is to get out of the "higher levels" sooner.
xxx
Getting the wheels down, is awfully noisy, the nose down angle will be steeper, all that contributes to the obvious passenger panick, so I am for the clean descent, even if the time is longer to FL140, I will be down to FL250 sooner.
xxx
Further, we recommend to do the descent on autopilot, with FL140 selected on ALT (in case the pilots have O2 supply problem). With the autopilot, we can get 6,000 FPM rate easy... Then when on speed at barber pole, I select speed hold... One thing I do in the simulator, is to enter in a "1 G" 90º bank (!) to initiate the descent, with the idea of getting off the the airway traffic below, and also to avoid getting the passengers to the ceiling of the cabin. I am concerned as to not spill their drinks...
xxx
As to "FL140", we in Argentina, or my Chilean colleagues, have a smile on the face. Crossing the Andes between Mendoza and Santiago, our MEA level is FL250, as we have "granito-cumuluses" to 22,000+feet in that area. After the Himalayas, we are second... The "Cerro Aconcagua" is 22,830 feet...
xxx
As to keeping the O2 when above 10,000 feet of cabin altitude, I assume people who live in La Paz, Bolivia (13,500 ft elevation) have oxygen masks hanging from the ceiling in their housing. They live perfectly well up there. So, don't worry too much below 15,000 feet. Was there a couple of times in my life (with an old 720B, their power was appreciated for takeoff).
xxx
Happy contrails