"No confusion, the ops are as detailed in the B747-400 training notes and AMM."
And what if the two books disagree, Denzil?
In the face of such confusion, my "source" has agreed to humour me and recheck his findings (hope to get an answer next week).
According to my airline maintenance manuals for the
GE powered 747-400, the following applies:
AUTO Operation For #1 ADP
1) #1 Engine Fuel valve Closed (in the air or on the ground) = ADP #1 runs
2) "TE Flaps" In Transit (air or on ground) = ADP #1 runs
3) "TE Flaps" not zero (in air) (for 0.3 seconds) = ADP #1 runs (for a minimum of 10 seconds)
4) #1 EDP less than 1400psi (for 0.3 seconds) (air or ground) = ADP #1 runs (for a minimum of 14 seconds after EDP returns to 1600psi).
For the
RR-powered 747-400 #1 ADP
1) #1 Engine Fuel valve Closed (in the air or on the ground) = ADP #1 runs
2) "TE Flaps" In Transit (air or on ground) = ADP #1 runs
3) #1 EDP less than 2600psi (for 0.3 seconds) (air or ground) = ADP #1 runs (for a minimum of 14 seconds after EDP output returns to 2,825psi).
I haven't any values for P&W aircraft, but they probably have the additional logic for Flaps Out of Up, like the GE-powered aircraft.
747 Focal...
I'm glad to say I haven't yet come across a case of flushing toilets activating these pumps
... but, yes, air-driven demand pumps can be very noisy at times....especially if there are four of them fitted (as often seen on P&W-powered aircraft). However, when recently checking for #4 ADP ops after pump control problem rectification, I couldn't hear it start up or shut down above the noise of the packs (I was standing at the nose gear with phones on at the time). Perhaps because the air vent for the #4 ADP is on the right hand side of the strut. I had to walk towards the engine to be able to hear it.
Regards.
Q.