Aaaahhh... never mind, I've done a search - I know what you're talking about now.The passengers do become upset, but its nothing to do with the air conditioning, which would probably be the last thing on their minds at that point.

"...which would probably be the last thing on their minds at that point."Thankfully, I don't have a picture of this effect... even when accidentally triggered by clumsy engineers :-hahCheers.Ian.

IanIt must take a while to repack the 'rubber jungle' afterwards, particularly on a 747. I imagine after doing this once you're really careful not to do it again...

"Since you have the schematic, I am just guessing but my thought is that they simply tied it to either switch so either one or the other (and also both) would cause the High Flow circuit to activate." Here's pilot confirmation of my findings, Paulhttp://www.pprune.org/forums/showthread.ph...551#post1007551One engine bleed switch off won't do it, but two will.A pack, will go to high flow when the other pack is switched off, however (in air with flaps up).Other than expected bleed duct pressure changes, the pilot says APU EGT is an indicator of high flow.Cheers.Ian.