A tiny hydraulic transfer pump question

[dorianR666]

I cant observe any difference whatsoever between hydraulic transfer pump switch being on and off, no matter what scenario I set up to test it. Is it implemented?

 

Example scenario:

- hydraulic transfer pump switch off (shutoff)

- start up right engine

- flight hydraulic system is at 3000psi, combined hydraulic system is at 0 psi

- crank switch to left

- combined hydraulic system eventually rises to 3000 psi

= so far everything behaves as expected

- crank switch to neutral

- combined hydraulic system starts to slowly drop

- hydraulic transfer pump switch on (normal)

- combined hydraulic system continues to slowly drop to 0, exactly the same way as when transfer pump is off

 

Why? I thought combined hydraulic system should be kept by the transfer pump at 2400-2600 psi, no?

 

Am I doing something wrong, are there some interlocks im missing?

Edited August 14, 2021 by dorianR666

[Golo]

35 minutes ago, dorianR666 said:

Am I doing something wrong, are there some interlocks im missing?

Yes, you have to disconnect external power after starting one of the engines and all will be well. Hydraulic transfer pump is inoperative if there is ext. power connected.

[dorianR666]

1 hour ago, Golo said:

Yes, you have to disconnect external power after starting one of the engines and all will be well. Hydraulic transfer pump is inoperative if there is ext. power connected.

Ah, I see. Thanks you.