I should add that fuel-as-ballast is an exception to what I wrote above. It's not really 'fuel' for the purpose (ie there for burning) but just another type of ballast. Theoretically you could pour lead fishing weights into the fuel tank to achieve the same effect but, of course, that's not practical. I've used fuel as ballast too. Damn glad I had when I happened to get ramped by CASA one day and was given a 'please explain' about the plane's CG being outside the envelope at ZFW. Wasn't far out, but that was the point of the ballast fuel.
Last edited by Tinstaafl; 10th October 2012 at 16:15.