Contract Con,
Sure, but I don't have any technical pubs with me to refer to...
My understanding is that the NG APU drives a seperate common shaft air compressor that supplies all the 'bleed air' for ground aircon and engine starting.
Have you noticed in the NG FCOM that it's recommended to operate both aircon packs on the ground, it's more economical for the APU.
Cheers, FD
