Cabin Pressurization Control
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Hi, can someone help me figure out the correct way to use the pressurization system.
According to the manuals, you should set 1000ft above your cruise altitude, easy enough. (by the way the scale is weird between 35 and 40, there are only two lines between 35 and 40 so figuring out where 37 is, is tricky)
However, the issue I have is during descent. I'm at FL370 and the manual, and descent checklist states you should reset the dial to field elevation plus 500ft. Should that be cabin altitude or aircraft altitude scale? because on the aircraft scale, that only goes down to 15(000ft).
And if I set it just as I start my descent, the cabin vsi descends but this makes the differential pressure increase and eventually trigger a CABIN DIFF HI warning.
Should I wait before setting the control to fiel elevation and and what point should I do so?
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I have the same question
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I own a pressurized airplane in real life. Before you take off, you set the cabin controller to the cruising altitude of the airplane using the lower scale. The upper scale then reads what your cabin altitude will be at that altitude. At TOD, you set the cabin controller to the field elevation plus 500ft on the UPPER (cabin altitude) scale. By doing this, you're ensuring that the airplane is completely depressurized 500ft before landing, but also keeping the cabin pressurized longer for added comfort.
If you forget to set it at TOD, and you had it set to an aircraft altitude that produces, say, a 6000ft cabin, you'll end up with a totally depressurized airplane at 6000ft in the descent.
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I own a pressurized airplane in real life. Before you take off, you set the cabin controller to the cruising altitude of the airplane using the lower scale. The upper scale then reads what your cabin altitude will be at that altitude. At TOD, you set the cabin controller to the field elevation plus 500ft on the UPPER (cabin altitude) scale. By doing this, you're ensuring that the airplane is completely depressurized 500ft before landing, but also keeping the cabin pressurized longer for added comfort.
If you forget to set it at TOD, and you had it set to an aircraft altitude that produces, say, a 6000ft cabin, you'll end up with a totally depressurized airplane at 6000ft in the descent.
@SinkRate said in Cabin Pressurization Control:
I own a pressurized airplane in real life. Before you take off, you set the cabin controller to the cruising altitude of the airplane using the lower scale. The upper scale then reads what your cabin altitude will be at that altitude. At TOD, you set the cabin controller to the field elevation plus 500ft on the UPPER (cabin altitude) scale. By doing this, you're ensuring that the airplane is completely depressurized 500ft before landing, but also keeping the cabin pressurized longer for added comfort.
If you forget to set it at TOD, and you had it set to an aircraft altitude that produces, say, a 6000ft cabin, you'll end up with a totally depressurized airplane at 6000ft in the descent.
This is perfect and answers my questions, thanks! While I have you here, if you could answer one more thing for me.
Let's say it's a nice day and you'll be flying at 7000ft, how would you go about flying unpressurized, do you set the controller to DUMP during preflight?
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@SinkRate said in Cabin Pressurization Control:
I own a pressurized airplane in real life. Before you take off, you set the cabin controller to the cruising altitude of the airplane using the lower scale. The upper scale then reads what your cabin altitude will be at that altitude. At TOD, you set the cabin controller to the field elevation plus 500ft on the UPPER (cabin altitude) scale. By doing this, you're ensuring that the airplane is completely depressurized 500ft before landing, but also keeping the cabin pressurized longer for added comfort.
If you forget to set it at TOD, and you had it set to an aircraft altitude that produces, say, a 6000ft cabin, you'll end up with a totally depressurized airplane at 6000ft in the descent.
This is perfect and answers my questions, thanks! While I have you here, if you could answer one more thing for me.
Let's say it's a nice day and you'll be flying at 7000ft, how would you go about flying unpressurized, do you set the controller to DUMP during preflight?
@Sunake You could do that, and yes it would work. But there'd never be any reason why youd want to. Weather is irrelevant, it's a comfort thing. Why would you want to fly around with a cabin altitude of 7000ft if you don't need to. Everyones going to feel groggy after an hour or two, and their ears are all going to be subject to popping from standard climbs and descents.
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I might add that almost all pressurized aircraft have a limit on how many times their airframes can be pressurized (or the total number of hours) before the airframe is scrap. I say almost, because Starship is one of the only aircraft, if not the only aircraft with a Type Certificate Data Sheet from the FAA that does not specify any airframe life limits!
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I might add that almost all pressurized aircraft have a limit on how many times their airframes can be pressurized (or the total number of hours) before the airframe is scrap. I say almost, because Starship is one of the only aircraft, if not the only aircraft with a Type Certificate Data Sheet from the FAA that does not specify any airframe life limits!
@Black-Square fascinating!
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I’ve only flown short flights up to 12000 ft so far, am I correct in thinking that for low level flights like that, you can just leave the pressurization altitude knob at 0 at all times and there is nothing to do?
