A320 manual pressurization control
 

Hi all

when dual cabin pressure sys fault the table you get on the ECAM gives you very approximate gates for the cabin altitude given aircraft FL. You should aim at around 300 ft/min in descent, but what other rule of thumb can be used? a specific Delta P maybe? when would you fully open the outflow valve on short approach, literally just before touch down?

Thanks

In the sim I find this a challenging task at the best of times, requiring a deft touch and considerable attention, neither of which I have in abundance.

The Airbus guidance is a bit ambiguous and even if you keep 300-400 fpm in the descent but then go full up on the control shortly before touchdown, you can still get obscene cabin climb rates.

Last time I tried this we briefed to have the cabin at 0 DP at the ILS platform altitude of about 3000', then took the control to full up as we intercepted the glideslope. While this does subject the passengers to 700 fpm rate of descent, it's vastly preferable to cocking it up and subjecting them to 3-4000 fpm climb as you cross the threshold and you're guaranteed neutral pressure on the ground.

On top of that, it's vastly beneficial for workload management on the approach. YMMV, of course.

In CRZ go to the setting given by the ECAM. No rush. it is not an emergency. One toggle movement up or down equals cabin rate change of 50'/min.

Whenever comfortable in approach (below 8000'), but preferably at platform altitude get the dif. pres. to zero.

Limit your V/S as much as possible for pax comfort.

Just as long as you don't have any additional problems to cope with then trim the system, as best you can, for maximum passenger comfort. However, if you know that you're going to be descending into a very busy ATC environment and you're not able to (nor shouldn't) give it your maximum attention... set the system to depressurise at a sensible height above the airport elevation, The last couple of thousand feet (unpressurised) isn't going to give you, or your pax, any drama. Or, weld a third seat into the flight deck and strap a FE into it!

. . you `could` say that in decomress from typical cruise alt - both altitudes will meet at about . . 20,000 - that would be for a eng 1 and 2 out situation (whilst you restarted the engines, or glided to a nice long runway for your landing . . .) in the 320.

For somethingelse that has caused the decompress then the outside altitude and cabin could meet higher up, naturally.