OK, this is really old (and a very belated thanks for the last answer!), but I have recently come back to the problem (if that's what it is!).

What this means, no power to the AC bus until the engines are started, unless ground power is on, is that there's no way to activate the usual external lights - Nav/Beacon - before engine start up. Surely that can't be how it is in the real C-130??

M