B737NG HYD Pressurisation

[B737NG_Pilot]

Question 1:
What is the significance of pressurising hydraulics during push back? (B737NG)

Is it only for charging the accumulator? Why can't we do it after starting the engines..

Question 2:

What's the best practise in pressuring Hydraulics? Should we pressurise both System A & B together, or should it be one at a time after an interval of few seconds?

[nick14]

Q1: what do you mean? I know some operators push back with the A pumps off as belt and braces for the nose wheel steering but I believe Boeing actually recommend having them on.

Q2: never heard of a specific procedure and I'm not sure of any issues of putting them both on at the same time but we do.

[RVF750]

B you can use without pin, but A needs the lockout pin installing in the nose.


Hint: I do like to have positive brake pressure when the tug wants to disconnect.