B738 Air Systems (Recirculation fans, Temperature control, Press controller)
Hello, I am studying in preparation for a B738 TR, and I have come across a few questions while reading about the Air Systems. I believe the answers to these questions will not have to be expanded enough to warrant four individual new threads, so I hope no one minds I'll put them all in the same thread.
1) The FCOM lists conditions for when L/R recirculation fans will be operating. All of these conditions stated include that both packs are operating. Will any of the recirculation fans ever be used during single pack operations? If not: why not?
2) For the Left/Right Electronic Controllers (Temperature controllers), are the designations "left" and "right" in any way related to the "left" and "right" designations of the packs, or is "Left/Right" just a way of keeping the two electronic controllers apart?
3) Without trim air being available, and both packs on the standby pack controls, is flight deck zone temperature selector always ignored (for both the left/right pack)?
4) From what I understand, the manual outflow valve control operates a dc motor separate from the automatic pressure controller. What about the alternate automatic pressure controller, does it also control a dc motor separate from both the normal pressure controller and the manual control?
Cheers!