Pressurization on during climb
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Something i have noticed two flights in a row now, there seems to be some bug with the pressurization system with 24, it didnt happen on my first flight because I did not need engine ice, but i turned on the engine de-ice these two flights, and the panel is in auto, packs are on, apu air and apu is off (does the same thing with it on though too), the cabin altitude just keeps climbing, and there is no Delta-P, but the panel is saying -1600 by the time your at about 10000 feet. Even with the engine anti ice yurned off it doesnt seem to work. Im using the same exact procedures i did in 2020, so i do not believe this is a user error or i forgot a switch type of a thing.
This new simulator just seems to be cursed.
Went a third time to troubleshoot what it could be and the FMC stopped working hahaha, back to 2020 it is.
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Serekoko, hi.
I think you are maybe getting the various systems mixed up. The APU cannot supply air for engine (or airframe) ice-protection. For those you require the ENGINE AIR switches ON. To pressurise the cabin requires the PACK switches to be ON and a supply of air, either from the APU or the ENGINE AIR. The APU cannot supply air to the packs above about 16,000 ft, that is why if the APU has been used to supply the packs with air during take-off, a change-over is made after take-off.
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I appreciate that info, i think you are missing the point i was trying to convey, the aircraft was not pressurizing with the packs on (with and engine air and/or apu air on or off), but i appreciate the reply.
I am mentioning the anti-ice because that was the only difference between the first flight in 2024, and the following 2 where the cabit didnt pressurize, just providing the info as a data point.
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You are welcome. I posted because you appeared to conflated two different systems of which one cannot operate from the APU.
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@Driver-Airframes so with the engine anti ice eliminated as a factor (sounds like based on what you explained), the issue i saw was with the packs, as long as they had (either/or) engine air or the apu air on. Which leads me to wonder, why would the packs not pressurize the cabin, since it works fine in 2020 and also in the first flight i did
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@Sergekoko During the climb the Packs draw their air supply from the engine. Thus ENG AIR switches should be ON, as should the PACKS. So long as you have set the PRZ controller it should work during climb.
During T/OFF the APU air can supply the packs vis the APU AIR switches. This has the advantage of allowing improved aircraft performance as less air is drawn from the engines.
FYI, it is normal during T/OFF to see a slight negative pressure on the cabin diff gauge on pressurised aircraft. This is done to avoid a ‘bump’ in the cabin pressure.
An image of what you see would be of interest.
Hot air for anti-icing can only be drawn from the engines and also requires ENG AIR switches to be ON. The PACKS do not feature in this area and anyway, APU cannot supply anti-icing air.
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And I just wanted you to know that you had the switches in the correct position.
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Absolutely, and i really appreciate it but as i clearly pointed out its the same exact procedure i did dozens of times in the 2020 version, so i wasnt asking for advice about the operation of panel switching, but i do appreciate you explaining it still, even though i really tried to make it clear the seitches were in the right position :)