rightrudder86
New Member
I'm studying for my aircraft systems final and i need to know how to caluclate rate of ascent for cabin pressure. any help?
Pressurization question
- Thread starter rightrudder86
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rightrudder86
New Member
I'm supposed to be able to calculate the rate of pressurization in FPM. Such as "taking off from KPHX, if the airplane is climbing @ 2200 fpm to 21,000ft, and the max. desired cabin altitude is 8000ft, then what is the rate of climb for the cabin pressure?"
B767Driver
New Member
rightrudder86 said:
Well you want the cabin to reach the desired cabin altitude prior to aircraft level off...assuming that the cabin will be at or close to max differential pressure. The reason for this is so the cabin pressurization system will not be bumping up against the positive pressure relief valves...causing pressure bumps for the latter part of your climb.
So we want to ensure a cabin rate of climb that gets to 8000's before the airplane levels off.
KPHX is about 2000' (Make sure I've got this right...I'm guessing)? So about 8.5 minutes to climb to FL210.
The cabin needs to climb 6000' in 8.5 minutes. So 6000/8.5 = about 700 fpm.
This rate of climb seems a bit fast to me...but most airplanes will be able to maintain a lower cabin pressure than 8000' at FL210.
Bandit_Driver
Gold Member
B767Driver said:
ever fly and E170? Those things always seem to have 8000' cabins