Airbus avionics ventilation
 

Anyone care to enlighten me by explaining and the difference between, "OPEN" "CLOSED" AND "INTERMEDIATE" circuit avionics ventilation....

FCOM 1, or DSC as it is called now.

WHY do you want to know this ?

You can not manipulate/influence anything !
This knowledge, It's NOT of any practical use. Honestly. - at least it was not during my previous 15k hours on this type.

Anyway if you still like, read the books as mentioned on previous post :)

It's been a while since I had to to use the info but I seem to recall it's handy to know when you have a MEL on the extract or blower in the Avionics bay.

Open Loop means avionics bay ventilated from outside. Closed loop means means skin valves are closed and bay is cooled from air conditioned air on OVRD.

Something like that anyways. I'll come back to clarify if I find the details. I know I filed them somewhere because it was quite the confusing issue at the time.