A330 Eng 1 S/D and Green Hyd Lost?
 

Hello to all A330 bus drivers,

what happens if I extend the slats on the A330 with the blue elec pump only?

In the rare occasion of a eng 1 failure and a green hydraulic low level the Eng Shut Down procedure suggests :ugh: before S/F extension to turn off the blue elec pump.

I think that leads to a HYD G+B SYS LO PR warning and a landing without slats. But why shouldn’t I try to extend the slats with a blue elec pump only? What can happen?

Thank you for enlightening me

FCOM > DSC > 29 > 10 > 20

NOTE On each system, the electric pump flow is about 18 % of the engine-driven pump flow capacity. It can be used to retract the surfaces, but should not be used to replace the engine-driven pumps.

You're overthinking things but what can happen? Worst case scenario the pump overheats and catches fire. The electric pumps are not the same as the engine driven ones.

https://www.flightglobal.com/airbus-...es/789.article

Got it
 

Thank you for the references. I agree — a landing without slats shouldn’t be a significant issue.

Using the electric pump may also lead to insufficient hydraulic pressure to power some flight controls while the slats are being actuated.

Nothing, probably. The flight controls have a demand priority system that would pretty much ensure no flow went to the slats hydraulic motors.

Not familiar with the A330 procedures but why not extend the RAT for approach and landing. The system diagram I am looking at shows it in the Blue system.

That's the A320, where blue system is electric or RAT, no engines.

A330 RAT is on the green system, normally driven by both engines. A340 is the same except engines 1&4.


https://cimg6.ibsrv.net/gimg/pprune....d150790f94.jpg
Image lifted from search engine cache of what looks like a failed garbage website.

It doesn't look like there's a priority valve on yellow or blue hydraulics.

I see. The diagram I saw was titled A330 but obvoiusly wrong.
So the A330 hydraulics are more like the A300 that I was familiar with, (13 years ago). I think the RAT was on Yellow.
I wonder why they changed the system order from B-G-Y to G-B-Y?
Dixi.

Airbus seems to keep what's on each system mostly the same between different models.
Gear + normal brakes - green
Flaps - green+yellow
Slats - green+blue
Alternate brakes - yellow
Replace 'blue' with 'electric' on the A350/A380.

Boeing calls it left/centre/right by where it's fed from. Except for the A300/A310, pretty much all RATs feed the centre-ish system. Can't guess why the A300/310 RAT is on yellow.

The widebodies have EDPs as primary power for all systems, whereas the A320 has an electric system. That means that while you want the gear on the centre system on the widebodies (so you can retract in case of engine loss), it needs to be on one of the side systems on the narrowbodies (so that it's fed from an engine + PTU from another engine).

This leads to the gear on the 757 being on the left system where on the widebodies it's all centre (because there is enough electric/air capacity to operate the gear).

Seems with Airbus yellow is always right and green/blue swap left/centre depending on which is more critical.