Hello. I'd like to ask - how does the Boeing 737-800NG hydraulics system look like? Does it have right and left side with engine pumps being primary ones, and electrical being demand pumps? Or does it have system A which works primarily and B which works as a backup?

 

And also one more question. When I was learning to fly that aircraft, in the flows, I saw "Spoilers - Disarm" in Climb-Cruise phase and "Spoilers - Arm" during the descent and landing. But why? Isn't it just safer to not disarm them?

 

Kind regards,

Mixer

 

 

I'd like to ask - how does the Boeing 737-800NG hydraulics system look like? Does it have right and left side with engine pumps being primary ones, and electrical being demand pumps? Or does it have system A which works primarily and B which works as a backup?

 

Bunch of great info over at http://www.b737.org.uk/

 

...to include this:

http://www.b737.org.uk/images/hydsch345.gif

 

 

 

in the flows

 

Reasons behind flows can be very odd. I'm guessing this operator had some reason to add this in there.

Thank you very much!

And also one more question. When I was learning to fly that aircraft, in the flows, I saw "Spoilers - Disarm" in Climb-Cruise phase and "Spoilers - Arm" during the descent and landing. But why? Isn't it just safer to not disarm them?

 

Kind regards,

Mixer

Unlike an Airbus, for example, Boeing spoilers don't need to be armed for takeoff. So after takeoff the spoilers would be disarmed anyway, The flow just verifies that. There is no need to arm the spoilers in flight and it might possibly lead to inadvertent deployment, so definitely safer to ensure they are disarmed. They only need to be armed before landing. Hence the flows you noticed.