...if da pilot thought he needed more thrust he might have cut off the generators that ran off the engine and then run essential electric systems off the propeller drive source.
How an Auxiliary Power Unit Works
http://www.flyingmag.com/how-an-auxiliary-power-unit-works/
http://www.bing.com/search?q=Boeing+787+auxiliary+power&FORM=QSRE6
Try this link for more on aux power unit
I have watched all the "Air Disasters" vids and am expecting my pilots license in the mail any day now.

Liberals are like a "Slinky". Totally useless, but somehow ya can't help but smile when you see one tumble down a flight of stairs!