In which configuration should the HYD pumps be in before engine start?

In which configuration should the HYD pumps be in before engine start?

The electric ones?In either case, with strong winds one electric pump (B system) can be left on during turn around. I think that's BS, but Boeing recommends it.

In either case, with strong winds one electric pump (B system) can be left on during turn around. I think that's BS, but Boeing recommends it.

Why do you think it's BS?

Why do you think it's BS?

Let me re-phrase. Unless winds are extreme, I think that's pointless.

I haven't got an answer:Should all HYD pumps (ELEC and ENG) be on before ENG start: Or should the ELEC ones be OFF, Or should ENG A and ELEC A be off?

The specific procedure varies from airline to airline. You can have the ELEC HYD pumps on at all times, if you want. Some airlines turn them on before pushback.Just make sure you don't turn on the A system with a towbar attached and not straight.

I understood from the manuals that it depends on the fact if the nosewheel steering pin is inserted or not for pushback (as far as I know it is with pb).If the pin is inserted (this is simulated with the pb of AES/GSX/PMDG/FSX) the elec pumps should both be OFF and both the engine driven pumps ONIn case the pin is NOT inserted with pb or towing, the A Pumps should both be OFF, the B elec ON and the B eng OFF.

The specific procedure varies from airline to airline. You can have the ELEC HYD pumps on at all times, if you want. Some airlines turn them on before pushback.Just make sure you don't turn on the A system with a towbar attached and not straight.

I think this is not correct. If the NW steering pin is inserted, the A eng pump can be ON.The hydraulics for the nosewheel steering is on Hyd Group A.

Hey Ed.I've read another place, that you can have all HYD Pumps on before Pushback if the pin is inserted. So that's what i'm gonna do.

Hydraulic pump switches should all be on prior to pushback if the following criteria is met: - Ensure ground personnel are clear of tow bar or bypass pin is installed.Now if bypass pin is unavailable then system A pumps should be off prior to pushback, also this would procedure would be used if you will not be pushing back.

I haven't got an answer:Should all HYD pumps (ELEC and ENG) be on before ENG start: Or should the ELEC ones be OFF, Or should ENG A and ELEC A be off?

I'm pretty sure you got your answer. "It depends!" :( And you're welcome for the additional information.

If the pin is inserted (this is simulated with the pb of AES/GSX/PMDG/FSX) the elec pumps should both be OFF and both the engine driven pumps ONIn case the pin is NOT inserted with pb or towing, the A Pumps should both be OFF, the B elec ON and the B eng OFF.

Engine driven pumps cannot be turned on with engine off, even if switch is in on ON position, and engine is off, the pump will be off.Before towing and engine start, all pumps switch position should be ON, since as far as i know, the tow pin removes hydraulic pressure from nose steering so that the tow truck can turn it, this happens regardless of either hydraulic system being pressurized or not.So if you want a clear answer: All hydraulic pumps should be switch ON prior to pushback and engine start. Don't worry about the low pressure light on the engine driven ones, they won't start running until engines are.

Engine driven pumps cannot be turned on with engine off, even if switch is in on ON position, and engine is off, the pump will be off.Before towing and engine start, all pumps switch position should be ON, since as far as i know, the tow pin removes hydraulic pressure from nose steering so that the tow truck can turn it, this happens regardless of either hydraulic system being pressurized or not.So if you want a clear answer: All hydraulic pumps should be switch ON prior to pushback and engine start. Don't worry about the low pressure light on the engine driven ones, they won't start running until engines are.

But you don't turn off the engine engine pump switches because you're energizing blocking solenoids. Those switches are always on except for maintenance or by QRH.

The airline I work for has:- ENG 1 and ENG 2 always ON. I.e they are never turned off unless there's a problem or maintenance is being carried out, and,- ELEC 1 and ELEC 2 are turned ON before engine start. (They are actually turned ON 5 minutes prior to pushback so that the pre-flight flight control checks can be carried).Note:>Zach is right; with respect to the ELEC 1 and 2 switch usage, it depends, and is sometimes different from airline to airline.Matt is also right. He outlined the reason why the ENG 1 and ENG 2 switches are always ON. You do this to extend the service life of the depressurization solenoid valve.Ashley Frew.