on that pic ,the plane is stationary (gs=0),just after push and engine start. (engines are at idle thrust,and also flaps=0 ) ,and both sys A hyd pomps off.
Many ops recomand sys A off for pushback,as a suppllementary protective meassure.
You don't want to meet some smart guy who'll forget to install the pin.I'd met one who forgot to remove it
so,why not the opposite?
