Originally Posted by
rippey
Question for current 604 drivers - would you expect to see the ADG out in this scenario? The video is blurry but I can’t see the ADG. My experience is limited to the 601 and Globals, but in both of those the ADG or Rat would deploy immediately following double engine failure. I am guessing that in the 604 the apu generator is brought online in a standby mode when the APU is running and in this case automatically takes the electrical load when the engine driven gens drop off, preventing the ADG from deploying?
That is likely. SOP for a Challenger is to start the APU during descent (usually below 10,000 feet), and transfer the bleed air for the packs from the engine 10th stage to the APU bleed air. The APU generator would remain in standby, but would come online immediately if both engine generators failed.