Originally Posted by
600ft-lb
Maybe because there is no ADP at pylon 2 and 3.
There are on some, AC demand pump was an option or vv.
I don't know VMGC is exactly, obviously to do with speed, I would suggest flap operation is the key here.
Added from DDG:
With Demand Hydraulic Pumps No. 1 or No. 4 inoperative, an engine failure
at the same position (1 or 4) on take-off will cause a hydraulic system loss,
preventing retraction of some landing gear, and will require secondary mode
(electric) operation of trailing edge flaps. Take-off performance (including
obstacle clearance) is thus based on gear and flaps extended.
Time required for retraction of the trailing edge flaps after take-off will be much
longer due to the slower operation of the electric drive (36 seconds for hydraulic
operation vs. 275 seconds for electrical operation). Consequently, the
Operations Manual charts 'Maximum Level Off Height' and 'Third Segment
Distance' may not be valid for this situation. It must be assumed, for
performance calculations, that flap retraction is accomplished at Maximum
Continuous Thrust.