ADP Run Logic on 747-400
Guest
Posts: n/a
"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.
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.
Guest
Posts: n/a
QAVION,
Thanks for the info. From what I can tell, and I would think where I am at, that there is a lot of literature on the ADP operation and none of it seems to agree.
The placement of the cooling intake and the exhaust was most probably responsible for you not being able to hear the ADP until you moved. They are designed to reflect away from the cabin.
Testing them this month and next at Paine. Hopefully the functional test guys will know how they are supposed to operate.
Thanks for the info. From what I can tell, and I would think where I am at, that there is a lot of literature on the ADP operation and none of it seems to agree.
The placement of the cooling intake and the exhaust was most probably responsible for you not being able to hear the ADP until you moved. They are designed to reflect away from the cabin.
Testing them this month and next at Paine. Hopefully the functional test guys will know how they are supposed to operate.
Guest
Posts: n/a
Here's an update on the ADP logic to add to the confusion....
My source tells me that he tried selecting Flaps 1 from Up on departure (in a 747-400 with GE engines)... and the ADP's did not run. This seems to fit the Boeing Maintenance Manual's "TE only" logic (on the ground with engines running). However, he tells me that when he went from landing config to UP in one go at the end of the flight, the ADP's didn't stop running until the flap indicator showed UP (i.e. LE's and TE's).
Perhaps there is some kind of EICAS indication delay, rather than a glitch in the logic? (e.g. after the TE flaps had stowed an electrical signal would have to be sent to the ADP via cards, wiring, etc and the ADP valve would have to close. The closed signal would then have to go to EICAS via wiring/computers, etc, to display the ADP-not-running indications. Perhaps by the time all this had happened, the inboard LE's would have already retracted?).
Rgds.
Q.
My source tells me that he tried selecting Flaps 1 from Up on departure (in a 747-400 with GE engines)... and the ADP's did not run. This seems to fit the Boeing Maintenance Manual's "TE only" logic (on the ground with engines running). However, he tells me that when he went from landing config to UP in one go at the end of the flight, the ADP's didn't stop running until the flap indicator showed UP (i.e. LE's and TE's).
Perhaps there is some kind of EICAS indication delay, rather than a glitch in the logic? (e.g. after the TE flaps had stowed an electrical signal would have to be sent to the ADP via cards, wiring, etc and the ADP valve would have to close. The closed signal would then have to go to EICAS via wiring/computers, etc, to display the ADP-not-running indications. Perhaps by the time all this had happened, the inboard LE's would have already retracted?).
Rgds.
Q.
