Message comes on when either center fuel pump is on and fuel quantity less than 2400 lbs.
I believe the FCOM says "fuel quantity less than 2400 lbs
and pump pressure low". Should the pump pressure go low at this magic value of 2400 lbs (approx 1.1 T) or should it go low at a value less than 2400 lbs? Also, would the altitude of the aircraft have a bearing on what volume of fuel the pumps would switch over?
I read something today about the center tanks having a "cheek tank" which determines how much total fuel is used by the center pumps...........