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-   -   Your airbus procedures : Fuel pumps ON or OFF during refueling ? (https://www.pprune.org/tech-log/604755-your-airbus-procedures-fuel-pumps-off-during-refueling.html)

C.M 28th Jan 2018 19:48

Your airbus procedures : Fuel pumps ON or OFF during refueling ?
 
A lot of operators have fuel pumps off while refueling takes places . But some other operators simply say ‘ airbus says all white lights out’ and that’s the end of the story. What does your SOP say and do you know a technical reason that would make it prudent to have fuel pumps off till refueling finishes ? ( it is very possible that the urge to leave them off is carried from operators who operated different aircraft in the past , but the technical reasons for other aircraft may not be applicable to airbus. )

Jimbo2Papa 28th Jan 2018 20:43

Definitely all white lights out with our SOP.

There's no reason why refuelling should cause anomalies with pressures and pre-flight, etc.

Why do you ask?

C.M 28th Jan 2018 21:17

If there are operators who do not set the Pumps ON until refueling finishes , it might be because of issues that resulted because of that , and I would like to be informed about it . My Previous operator had this as SOP with no explanation ( their entire OMB -SOP was the exact FCOM-SOP written with their own minor modifications so we very seldom bothered with the FCOM SOP. ) Now that I’m with a different operator I’d like to be sure exactly when I raise a topic , to have valid justifications for it .

Jimbo2Papa 28th Jan 2018 21:34

I would say you're correct in your assumption that there are operators who have had "issues" that have resulted in modified SOP's peculiar to their company re: fuelling procs, etc
Hard lessons learnt maybe.
As far as I'm aware of Airbus wide procedures there's no direct published procedure to extinguish the white lights before, during or after refuelling.

hans brinker 28th Jan 2018 23:22

C.M

We have a note in the SOPs: "During refueling, FUEL PUMPS must remain OFF".
I can only think of one issue why: during re-fueling with the CTR TK pumps ON, on the aircraft with CTR TK XFR System the CTR TKs are pushing fuel from the CTR TK into the WNG TKs while fueling. I guess the worry is the WNG TKs could be overfilled by this. They should not, the CTR TK PUMPs should switch OFF at high WNG TK level, and refuel valves should close when a high fuel level is detected...

hans brinker 28th Jan 2018 23:31


Originally Posted by Jimbo2Papa (Post 10034465)
Definitely all white lights out with our SOP.

There's no reason why refuelling should cause anomalies with pressures and pre-flight, etc.

Why do you ask?

Our SOP have a note to wait with the foul pumps until fueling is done. I don't know what is better, but I really think it doesn't matter if you have white lights ON until the first engine is started...

TURIN 29th Jan 2018 00:28

I'm not sure about the Airbus family, but on many types the cross feed and refuel lines (gallery) are the same.
In theory, if pumps are on, then certain areas of the refuel 'gallery' could be fighting the aircraft pump pressure during refuelling. At best this could slow refuelling and at worst damage componants.

Maybe.

Capt Fathom 29th Jan 2018 01:36

Do you think that maybe Airbus did not consider all this when designing their SOP's?

hans brinker 29th Jan 2018 03:38

I would hope so, but they did not write the manual clearly enough for there to be no ambiguity....

Cak 29th Jan 2018 08:07

There is no reason to leave them off. There could be an issue with fuel spillage if CTR PUMPS OR XFRs are not set to OFF and FUEL MODE SELECTOR is left n MAN position.
There was something else on some older models long time ago but I cannot recall exactly what was it :)
So, maybe it just stayed as part of SOP for reasons no longer in force

MATMAX 29th Jan 2018 12:56

basically technically , during a refuelling , whatever the Aircraft type is , Boeing or Airbus , everything must be off , it is a question of safety ...
i do not see why the fuel pumps should be on , the fuel pumps are low pressure pumps and are just needed to feed the high pressure pumps ...
now , by experience , i have seen few times , where , on some Airbuses (old 340) , the total fuel qty was varying (until 500 kgs) , between pumps off and then on , the main reason being filling in the collector cell ... i guess it is the reason why , depending on the company Policy , some are asking to put the pumps on ...
as a tech , i am leaving the pumps off , then , when the refuelling is completed , i am switching the pumps to on , and waiting around 10 mins to see if the total qty is dropping down or not , just my 2 cents here ...
anyway , leaving the pumps on ON is disturbing Nothing during a refuelling ...
refuellings are managed by the FCMCs , depending on the qty required , the FCMCs will open and shut the refuelling valves , maintain balancing , etc ...
in a perfect world , Nothing special is supposed to happen , except if some valves are having internal leaks , if there are no leaks in the tanks , etc ...
normally , until the FCMC is not stopping the refuelling , Nothing is supposed to be done , but , thats the duty of the person in charge of the refuelling ...

Fursty Ferret 29th Jan 2018 13:51

We switch ours off to reduce the electrical transient when switching from GPU to ship's power. Will reduce APU fuel burn and on a very hot day will give noticeable boost to air con.

MATMAX 29th Jan 2018 14:27

Gents , all fuel pumps are electrically powered and mechanically geared ... during refuelling , there are fuel vapors everywhere ...
i think that all of you will imagine easily what can happen in the case of a pump failure or whatever ...
i am sure that all of you heard about TWA800 and the SFAR88 ...
in maintenance , we must study and practise the FTS and CDCCL , maybe you should read stuff about these ... again , just my 2 cents ...

Highway1 30th Jan 2018 00:13

The Airbus AMM allows APU starts during refueling so a pump is going to run whatever you have selected on the Flt Deck.

ACMS 30th Jan 2018 00:15

The Tanks are not empty and the pumps are always completely covered with fuel. If the tanks were empty the fault light in the associated pumps would illuminate.
Furthermore the Tanks are hardly ever completely full so there will always be fuel vapor present unless there is an inerting system fitted ( A350 )

Just follow your Airbus SOP for the type you are on.

SIMPLE.

vapilot2004 30th Jan 2018 11:04

On this aircraft, the refuel gallery is separated from the main fuel pump pressure by the de-fuel valve.

MATMAX 30th Jan 2018 12:03


Originally Posted by Highway1 (Post 10035740)
The Airbus AMM allows APU starts during refueling so a pump is going to run whatever you have selected on the Flt Deck.

not really sure about this , but for sure , other documents are recommending not to do it ...
not only a fuel pump will be activated during the APU starts , but relays , exciters , etc ...
if you are on battery , the DC pump will run , on the GPU another AC pump , both of them located on the aft spar , LH side ...
where the fuel truck is plugged to the Aircraft ...?

MATMAX 30th Jan 2018 12:11


Originally Posted by ACMS (Post 10035745)
The Tanks are not empty and the pumps are always completely covered with fuel. If the tanks were empty the fault light in the associated pumps would illuminate.
Furthermore the Tanks are hardly ever completely full so there will always be fuel vapor present unless there is an inerting system fitted ( A350 )

Just follow your Airbus SOP for the type you are on.

SIMPLE.

the fault light means low pressure at the pump outlet , it has Nothing to do with the fuel tank qty , empty or full ;)

totally agree with this : "Just follow your Airbus SOP for the type you are on."

bcgallacher 30th Jan 2018 12:42

On earlier Airbus types a boost pump in each inboard tank pressurised a small valve allowing the refueling manifold to drain into the inboard tank after refueling with the aircraft pumps then switched on. During refueling when the selected quantity was reached the refuel valve for that tank would close but if the boost pump was running fuel would still enter the inboard tank uncontrolled through the drain valve.

Highway1 30th Jan 2018 12:52


Originally Posted by MATMAX (Post 10036280)
not really sure about this ,

Look it up then A330 AMM 12-11-28 P301:

(17) APU starts or shutdowns are permitted during refuel/defuel procedures.

Airbus even allow refueling with one engine running (Ref. FCOM 2.01.30)


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