I picked up the CRJ 700 regional airliner yesterday and it’s a lot of fun, despite a few minor glitches. Most were control binding issues (which I’m sure will get worked out, I have a popular type of input device) and the extra work of inputting my waypoints to the FMS manually, but that’s no biggie.
However I did have a problem I couldn’t figure out, with the cabin pressurization system: about halfway through the flight, somewhere around FL350 I got a warning about low cabin pressure: the cabin altitude was reported as about 14,000 feet – way higher than normal indicating low pressure inside the cabin. I deployed oxygen masks to keep my passengers alive, and kept an eye on things.
Cabin altitude continued going up, so I started descending so eventually the pressure might equalize back to something my passengers could breathe…
…however the cabin altitude never went back down. Even as I went below 15,000 feet the cabin altitude was reporting 20,000 feet with a constant change rate of +300.
Is it possible that I accidentally pushed a button that causes a constant slow decrease of cabin pressure, even when that requires actively pumping air out of the cabin to maintain a lower pressure than the surrounding static air?
I checked the PDF manuals but aside from mentioning that cabin pressure controls exist I could find no explanation of how they work or what you’re supposed to set them to.
My guess is he probably didn’t. There’s a lot of small things people forget and it screws everything up. Hopefully this isnt a bug and just a user error.
Landing elevation is set properly (or at least within a couple hundred feet). Can see that in the screenshot. Regardless, it wouldn’t cause an issue like described.
I would look more towards the pack/bleed air switches. But not seeing any CAS messages, so those are probably all set correctly. You can pull up an ECS synoptic on the MFD to show more details. The switches to do that are on the center pedestal. Am away from my computer, so going off memory.
I’ll see if there’s any. I did try poking the cabin pressure controls after the problem started (I did not touch them beforehand). Unfortunately the manual does not explain what the individual cabin pressure controls do, or how they affect the operation of the plane.
I searched for “cabin”, “pressure”, and “cabin pressure” in all the PDFs, and found only the references to the existence of the cabin pressure controls on the upper cockpit panel, and a mention of altitude limits for single-pack operation which didn’t sound relevant to a default flight state.
Ok, here’s the overhead panel from a video capture I took while trying to investigate it. I’ve turned on passenger oxygen, but I think at this point haven’t touched any other overhead controls.
When you are taking off and landing you set the cabin pressure with that knob in the top right. Use the landing elevation of the airport. See if that helps.
Now that I know I should be looking at the bleed settings, I’m having more luck with the manual! It seems that the ISOL switch was on closed, when it should have been open.
I’m not sure how that happened and why it doesn’t seem to have happened on the flight I took this morning, which had no cabin pressure problems, but I’ll keep a closer eye on it.
Can you point me to the section of the manual that explains the proper usage of that dial? I’d like to know how to read out its current value (since there’s no readout by the dial itself). Thanks!
Ok for future reference, here’s the two relevant bits of information that I have now found in the manual, both in Vol 3 Tutorial.pdf!
First, I think my main problem was caused by (accidentally?) switching something in the bleed settings section, which I’ll keep a more close eye on on future flights:
Second, the landing elevating setting can cause problems with pressure equalization if it’s incorrectly set. It’s unclear looking at the top panel what’s going on because the readout is on the MFD so you probably don’t see it onscreen while you’re adjusting it:
Between understanding these two systems better and making sure they’re correctly set on takeoff, I’m confident I’ll be able to resolve any future surprises.
I’m having the same issue and following these steps I haven’t been able to fix it. If possible could somebody make an exact list of steps they followed to solve it.
Thanks
I just never had the problem again after the first time. I am not certain what caused it, but believed it to have been accidentally switching off the packs or some other problem. This may be wrong.
I have no procedure for fixing it other than “check everything”.
