Originally Posted by
Jet Jockey A4
Don't know the GIV but what about electrical hydraulic pumps to back up the engine driven pumps? Wouldn't you have to turn off those too?
The GIV only has a single electrically-driven hydraulic pump - the "aux pump". On the ground, it is not capable of supplying hydraulic pressure to any of the primary flight controls affected by the gust lock system. It can be used to lower or raise the flaps, though doing so takes much longer than when the flaps are being driven by engine hydraulics.
The main function of the aux pump on the ground is to supply hydraulic pressure to raise the main entrance door, and to fully charge the brake accumulator prior to setting the parking brake. It can also be used to open or close the nose and main gear doors on the ground.