A330 EDP Overheat Procedure

[Killaroo]

Lets say you have a Blue Pump Overheat with associated ECAM to switch it off.
Then lets say the overheat message goes out after 20 minutes. By now you are configured for approach and all associated checklists have been performed.

The ECAM Status Page suggests you can turn the pump back on.

Would you hesitate to do it, or happily do it?

Would you be concerned about a second overheat, and - who knows - maybe something worse as a result?
Does the risk outweigh the benefit?

Opinions welcome!

[Dream Land]

I'd turn it on

[vilas]

As long as all procedures from STS have been performed you should turn it on. Nothing worse than overheat coming on again can happen. Since you are already configured for approach if it comes on again put the pump off again asked by ECAM, clear ECAM and status and continue with approach and landing.

[Killaroo]

How do you know that? What was the cause of the original overheat? Suppose a bearing in the pump has gone, or the lubrication system has failed and the pump is grinding metal on metal?
A Yellow Electric Pump O/H has burnt at least one A330 to the ground. Hydraulic fires can happen. You got away with it once - why take a second chance?

What if you put it on, set up for a 'normal' landing and it goes again?
Go Around and repeat the whole procedure again?

[Goldenrivett]

A Yellow Electric Pump O/H has burnt at least one A330 to the ground.
If you are referring to some incidents before 1997, I believe the aircraft had nobody in the flight deck to turn the pump off, when the overheat warning occurred during ground maintenance. http://www.flightglobal.com/news/articles/airbus-issues-hydraulic-pump-warning-after-a330340-1386/ "Airbus in the meantime, is looking at alternative pumps for the A330/340." I think Airbus has found alternative pumps by now. Presumably you would be able to turn the pump off again, should the warning reoccur?

Would you not have turned on the yellow pump in this scenario?
http://www.aaib.gov.uk/cms_resources.cfm?file=/Airbus_A319-111_Airbus,_G-EZDM_08-09.pdf

[Bearcat]

Leave It off...it overheated for a reason. You have green and yellow left. More or less norm ops.

[Killaroo]

It's rather like the old CB reset attitude.
A CB pops - "give in two minutes cooling, then reset it". Remember that?
Then there were lots of fires when the CB's failed the second time, or when overheated wiring caught fire on second power application.
Now the policy is - "it popped for a reason, don't tempt fate".
The CB's have been removed from the cockpits of Airbus a/c.
Yet we are told to reset a hydraulic pump after an overheat for unknown cause.

In an extreme emergency you may have no choice.

In a stabilised scenario, why risk a fire or further damage?

[vilas]

Killaroo
The feeling I get is you are not asking but telling something. You should tell this to AIRBUS through your company only they can examine all the angles.There can be an unending discussion and still you will not be sure of being correct.

[grounded27]

Reminds me of a more severe situation on a 74C that lost oil on one engine down to minimums in cruise, shut it down. Turn it back on during final.

[Goldenrivett]

Yet we are told to reset a hydraulic pump after an overheat for unknown cause.
I think you are confusing the resetting of a tripped CB for an electric pump, which has drawn too much current, which is not recommended.

However, you do not physically "turn off" an EDP. It will continue to rotate until either the drive shaft shears, or the engine is shut down. See http://www.eaton.com (http://www.eaton.com/ecm/idcplg?IdcService=GET_FILE&allowInterrupt=1&RevisionSelectionMethod=LatestReleased&Rendition=Primary&dDocName=CT_195634)

When you "turn off" an EDP, you move the "yoke" (wobble plate) to a position where the delivery volume is zero. If you are concerned about a bearing in the pump has gone, or the lubrication system has failed and the pump is grinding metal on metal? then simply turning an EDP off will not solve your problem.

[nitpicker330]

"Let's say you have a Blue Pump overheat......."

Ahhhh I've looked through all of the A330 FCOM Abnormal and Emergency section for Hydraulics and there is no ECAM for a EDP overheat....( to be honest I don't know why there wouldn't be an ECAM but I couldn't find one? )


There are ECAMS for Green Blue or Yellow RSVR overheats.

The status page will show depending on which system----

APPR PROC-- IF OVHT OUT: ENG PUMP 1 and or 2..............................................ON
IF HYD NOT RECOVERED: LDG DIST PROC............................................APPLY

[spannersatcx]

FAULT -- Illuminates with ECAM message for:
1. Reservoir Low Level
2. Reservoir Overheat
3. Reservoir Low Air Pressure
4. Pump Low Pressure (inhibited on ground, engine stopped)
The Light extinguishes when the Switch is selected OFF, except for an Overheat -- stays illuminated as long as condition exists

[Killaroo]

Goldenrivett - good point. BUT the pump is offload when switched off.
That may make all the difference.

[Goldenrivett]

Killaroo
BUT the pump is offload when switched off. That may make all the difference.

Correct. Unless the cause of the original overheat problem has been removed (e.g. PTU selected off in post #5), then the system is likely to overheat again. See hydraulic-overheating (http://www.machinerylubrication.com/Read/680/hydraulic-overheating)

In which case, simply turn the pump off again (to off load the system), and continue the approach (having made the appropriate landing distance correction beforehand.) You can't be any worse off.

Edit. See interesting fact sheet on Skydrol fire resistance.
http://www.skydrol.com (http://www.skydrol.com/pages/faqs.asp)

[fruitloop]

Was the Blue electric pump running ??

[Microburst2002]

It is a master caution, right? All you have to do is isolate the failure and you are not going to die.

Switch is on for the approach. In case it overheats again, isolate it once more and that's it. You already prepared for the landing distance and everything, so relax and enjoy.

[Tinwacker]

Suppose a bearing in the pump has gone, or the lubrication system has failed and the pump is grinding metal on metal?

The EDP lubrication system is the system hydraulic oil.
If you had a bearing failure and or grinding meat on metal then the EDP quill shaft will be shearing very soon and so disconnect that pump from the gearbox permanently.