Sky9,
If I heard correctly there was much talk from the passengers of a rapid drop in temperature before the emergency descent.
This would indicate a sudden 'out of control' pressurisation drop which would lead straight to what you so rightly say was the second stage - the drop.
If the a/c was cruising at mid FL30's then the pressure sensor would immediately detect 30 something thousand feet - which is far less than the trigger of 14,000' and bingo. Rubber jungle.
The masks didn't actually deploy at 14,000' but hopefully soon after the pressure drop?
I guess we'll just have to wait a few years for the AAIB to publish their report to see what actually happened.
DB
