How fascinating.
Unfortunately, you force me to pose a secondary question:
How does increasing cabin pressure from standard 5,600 (with a 'normal elevation' airfield such as your JFK example) to ~8,000, reduce the amount of oxygen to deprive a potential fire? Is this MAN LDG ALT only used during the cruise portion and NEVER during descent, or can AUTO be reselected even just a few thousand feet after descent has begun?
E.g: flying over the pacific from, say KLAX to YSSY, you get your smoke/fire warning relatively near to YSSY (say 250NM away), so you won't necessarily be diverting (or even if you are, my question still stands)... you would do the checklist to this point, then set LDG MAN, whack in 8,500 causing cabin pressure to increase from 5,600 and depriving any potential fire source of its needed oxygen (how?). This cabin pressure change occurs over what time frame? If you were to divert, T/D would be closer so the cabin pressure perhaps wouldn't have even made it to 8,500 by the time you start your descent - making it reduntant? Do you see my little confuzzlement?
Response(s) muchly appreciated,
TP
Last edited by Tonic Please; 28th June 2012 at 08:02.