A320 Y hydraulic pumps
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Originally Posted by Aircraft Maintenance Manual 29.13.00 page 1
The Yellow electric pump is in the Yellow hydraulic compartment. It supplies the Yellow main system with hydraulic power when necessary (failure of the engine or engine pump). It is set to on from the flight compartment. It also starts when the aircraft is on the ground and a selection is made to operate the cargo doors.
Originally Posted by Aircraft Maintenance Manual 29.24.00 page 5
Y ELEC Pump Performance:
- displacement = 4.3 ml/rev.
- delivery pressure at zero flow = 206 + 3 - 0 bar (2987 + 43.5 - 0 psi)
- delivery pressure at 23 l/min (6.08 US gal/min) = 196 bar (2842 psi)
- delivery pressure at 32 l/min (8.45 US gal/min) = 150 bar (2175 psi)
- displacement = 4.3 ml/rev.
- delivery pressure at zero flow = 206 + 3 - 0 bar (2987 + 43.5 - 0 psi)
- delivery pressure at 23 l/min (6.08 US gal/min) = 196 bar (2842 psi)
- delivery pressure at 32 l/min (8.45 US gal/min) = 150 bar (2175 psi)
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In a dual engine failure situation assuming you got your APU started and running, what is the state of the electrical configuration? Since the APU is an identical generator to either engine's, will there be a full recovery of the electrical systems?
Edit: Oops I do apologise posting this reply on the wrong thread. I was doing a search and ended up having a few threads open simultaneously and I only just realised I posted an electrical question in a hydraulics thread.
Edit: Oops I do apologise posting this reply on the wrong thread. I was doing a search and ended up having a few threads open simultaneously and I only just realised I posted an electrical question in a hydraulics thread.
Have a look at FCOM 3.02.29 HYD Y ELC PUMP LO PR or OVHT
It is suggesting that it can be used in the event of a PTU and Y ENG PUMP failure. I haven't seen though where the procedure is written to turn it on in the first place. Vol 1 implies that it can only be used on the ground but that is a bit of red herring. I look forward to the definitive answer.
It is suggesting that it can be used in the event of a PTU and Y ENG PUMP failure. I haven't seen though where the procedure is written to turn it on in the first place. Vol 1 implies that it can only be used on the ground but that is a bit of red herring. I look forward to the definitive answer.
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Dream 747, actually your question is relevant here:
It is not the same to have two engines inoperative and no APU than two engines inoperative with the APU running. The latter is much less stressing for the crew, to say the least.
So, with APU running, the question remains: Y ELEC PUMP, yes or no?
If the Airbus engineers don't use it in the procedure, it is because something could be not OK with that. There's a few things to consider: The output power of the Y ELEC is very limited, it seems.
If I was to use it, I would turn the PTU OFF first, so the elec pump wouldn't also have to power the green system. Then I would turn the Y ELEC ON and use it: Conf 3, then turn it off again.
As an added thought, APU ON take offs could could become standard procedure when there are birds in the airfield.
It is not the same to have two engines inoperative and no APU than two engines inoperative with the APU running. The latter is much less stressing for the crew, to say the least.
So, with APU running, the question remains: Y ELEC PUMP, yes or no?
If the Airbus engineers don't use it in the procedure, it is because something could be not OK with that. There's a few things to consider: The output power of the Y ELEC is very limited, it seems.
If I was to use it, I would turn the PTU OFF first, so the elec pump wouldn't also have to power the green system. Then I would turn the Y ELEC ON and use it: Conf 3, then turn it off again.
As an added thought, APU ON take offs could could become standard procedure when there are birds in the airfield.
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For readers who may have been lost in detail...
in general terms...
Electric pumps almost always have less flow than eng driven devices.They are capable of full pressure but flow rates are much less therefore for hi flow devices pressure will drop markedly.
Engines, even if not operating in flt will in most cases have sufficient power to generate hyd pressure if still selected on , pump is OK and fluid level sufficient.Witness how quickly hyd pressure comes up during starter ops prior to light off.
in general terms...
Electric pumps almost always have less flow than eng driven devices.They are capable of full pressure but flow rates are much less therefore for hi flow devices pressure will drop markedly.
Engines, even if not operating in flt will in most cases have sufficient power to generate hyd pressure if still selected on , pump is OK and fluid level sufficient.Witness how quickly hyd pressure comes up during starter ops prior to light off.
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So, with windmilling engines, Would be have enough power to set landing configuration?
In any case, at least on the ground without any aerodynamic loads, the yellow elec can lower the flaps. I wonder if that would not be the case when in the air at, say 200 Kt.
In any case, at least on the ground without any aerodynamic loads, the yellow elec can lower the flaps. I wonder if that would not be the case when in the air at, say 200 Kt.
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It will it is just slower with the lower flow rate.The pump will produce full pressure but will sag with load but it will deploy whatever it is pushing.
I am reasonably confident a windmilling engine would produce enough to run hyd's with flow limits.There are obviously some issues with having elec power to allow commands to made of the surfaces / device.
Consult the MM and NNC for further info
I am reasonably confident a windmilling engine would produce enough to run hyd's with flow limits.There are obviously some issues with having elec power to allow commands to made of the surfaces / device.
Consult the MM and NNC for further info
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The Yellow and Blue pumps are interchangeable.
The blue elec pump u/s is non-dispatchable so it is quite common to swap the serviceable Yellow for the Blue, non main base, to dispatch the aircraft.
Dual Engine failure high up would be within the windmilling re-light envelope therefore EDPs still available, if you dropped out of the envelope would you not attempt an APU start for more puff anyway thus giving you the electric power for ACMP? Being in engineering have no idea on the QRH/FCOM procedure.
As for the flow/delivery rate of the electric pumps, I regularly retract the Aircraft undercarriage (on jacks) using the yellow pump through the PTU, bit slow and whines a bit but it gets up there!
The blue elec pump u/s is non-dispatchable so it is quite common to swap the serviceable Yellow for the Blue, non main base, to dispatch the aircraft.
Dual Engine failure high up would be within the windmilling re-light envelope therefore EDPs still available, if you dropped out of the envelope would you not attempt an APU start for more puff anyway thus giving you the electric power for ACMP? Being in engineering have no idea on the QRH/FCOM procedure.
As for the flow/delivery rate of the electric pumps, I regularly retract the Aircraft undercarriage (on jacks) using the yellow pump through the PTU, bit slow and whines a bit but it gets up there!
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Worth noting that the EDPs will provide some useful pressure right down to approach speed so you are using the yellow as a top up.
Having yellow hyd gives a lot of advantages, configuration is one but braking/steering is also useful (newer A/C use yellow for nose wheel steering).
On the elec configuration subject. After a dual eng fail or Emergency Elec Config, even if you recover 1 or 2 main generators the essential buses remain supplied by the emergency generator until reset on the ground although other services are recovered through main buses.
Having yellow hyd gives a lot of advantages, configuration is one but braking/steering is also useful (newer A/C use yellow for nose wheel steering).
On the elec configuration subject. After a dual eng fail or Emergency Elec Config, even if you recover 1 or 2 main generators the essential buses remain supplied by the emergency generator until reset on the ground although other services are recovered through main buses.
