IFIX,
There is a way to do what your talking about on the Classic for sure because as I stated previously we would do this when someone wanted to smoke on the main deck below the cockpit. I will now go find my systerms manuals from my last flying job (it's been 6 years since retireing from flying) and see if I can figure out exactly how I accomplished that. My memory is not quite the same now. I do realise that the 400 is different.