Bellerophon,
Those who have used both “Demand” and “Pressure” breathing systems know the difference between them. Those that haven’t will learn it as soon as they take their first breath wearing a real “Pressure” breathing system!
I must miss something here. The quick donning masks you can find on a 737 or A320 are "demand" but can be regulated to Normal, 100% or Emergency (emergency being positive pressure regardless of demand).
What's the difference with the Concorde apparatus?
Regarding the VSI, it seems to me that the VSI installed is the same liquid crystal type you can find on an ATR42 or non-EFIS 737.
On this picture
http://www.!!!!!!!!!!!!!!/open.file/094078/M/ I can't find the digital reading you are talking about.
Surely you can enlighten me.
Thanks!
