What is the reason for turning off fuel pumps after shutdown.(a320)

[FlywithPark]

It is not easy to find the specific reason for turning off fuel pumps after shutdown for a320.
Could anybody explain this for me?
Thank you.

[pineteam]

Since you don’t need them why keeping them on? The wings pumps run all of time unless you switch them off.
Also during refueling, if fuel pumps are on there is a chance of fuel spilage. Can’t find any references for this but it happened quite recently in our fleet.

[vilas]

31st Jan I quoted the following from airbus.
Regarding the operation of fuel pumps in standard/normal conditions, we would like to confirm that Airbus recommendation is to switch OFF all fuel pumps at the end of the flight, and to turn them back ON during the cockpit preparation.
The references in the Airbus operational documentation are the following ones:

- At the end of the flight, Airbus SOP (Refer to FCOM-PRO-NOR-SOP-22 P 2/4) requests the flight crew to set FUEL PUMPS to OFF

- During the cockpit preparation, Airbus SOP (Refer to FCOM-PRO-NOR-SOP-06 P 3/20) states “It is a general rule to turn off all white lights during the scan sequence; therefore, these actions are not listed here”, namely to turn OFF all white lights for all the related systems.

The reason for this policy is to avoid operation of fuel pumps in an empty fuel tank, and also avoid unwanted fuel transfers (which can affect and potentially abort refueling process). That is the reason why the recommendation to switch OFF the fuel pumps before refueling is not explicitly provided into the FCOM, because this recommendation is implicitly covers by SOPs in standard operations (i.e. when refueling is performed before the cockpit preparation).
Please be informed that there are no restrictions/limitations to have fuel pumps running during the refueling as long as they do not run dry (in an empty tank, which in any cases should never be more than 10 minutes).

However, the general recommendation (not mandatory) is to have the fuel pumps switched OFF during refueling, in order to ensure that the possibility of pump dry running is avoided. It is particularly relevant for the center tank pumps, because the center tank is most of the time empty at the end of the flight. Switching OFF the center tank pumps ensures in all cases that they do not run during refuelling.

When performing the cockpit preparation, it is assumed that the refuelling (if needed) has been performed previously. As a result, if Airbus SOPs are well applied, all the fuel pumps will be correctly switched OFF during refueling.

[vapilot2004]

A longer discussion was just recently had here. (https://www.pprune.org/tech-log/604755-your-airbus-procedures-fuel-pumps-off-during-refueling.html)

[tdracer]

Airbus doesn't close the spar valve when you set the fuel switch to CUTOFF, just the engine fuel valve (note that this is different than Boeing - Boeing closes both the engine valve and the spar valve when you select CUTOFF).
As a result, if there is a bad seal on the engine cutoff fuel valve, the pressure from the boost pumps can cause fuel to leak past the valve and into the combustion chamber. That can cause a major tailpipe fire on the subsequent start.

[Goldenrivett]

Hi tdracer,
Airbus doesn't close the spar valve when you set the fuel switch to CUTOFF,

Airbus calls the spar valve "LP fuel shut off valve"
FCOM DSC-70-40: Shut-Off Valves
"Moving the ENG1 (ENG2) MASTER switch to OFF directly commands the closing of the LP and HP fuel shut off valves for that engine's fuel system.
It also closes the fuel return valve and opens the bypass valve."

[FlightDetent]

@vilas Thanks again. You seem to have raised all of the questions with Airbus, that all of us mere mortals have. How you managed, I can only speculate that vilas is at least the second reincarnation as a TRI/E.:E

BTW: do you not think it's unfair of AIB not to adjust the FCOM accordingly? I read the explanation with a bit of sadness.

The airline that trained me the best went to great lengths to wipe off the habit of leaving the pumps OFF, citing the no-white-lights rule. Now, 7 years later on the internet I read that it does not apply to Fuel Pumps before refuelling ends? Yuck. And maybe that the AMM even specifies so!

Their logic that SOP are well applied because during CKPT PREP the re-fuelling is finished is utter rubbish. That was NEVER true at any turn-around, since A320 day 1.

[tdracer]

Hi tdracer,


Airbus calls the spar valve "LP fuel shut off valve"
FCOM DSC-70-40: Shut-Off Valves
"Moving the ENG1 (ENG2) MASTER switch to OFF directly commands the closing of the LP and HP fuel shut off valves for that engine's fuel system.
It also closes the fuel return valve and opens the bypass valve."
Apparently Airbus finally wised up and made a change to close the "LP valve" because it didn't use to be that way (A300, A310, at least some early A320).
Not that Boeing didn't do the same thing - early 747s didn't close the spar valve either - after a number of hot starts/tailpipe fires they changed to shut down both valves.

[vilas]

FD
do you not think it's unfair of AIB not to adjust the FCOM accordingly? I somewhat tend to agree with you there. But I think all manufacturers play close to their chest. It may the fear of law suites. They tell what you need to operate the machine. But they will answer the customer query. So ask them under Tech Request. But then some airlines control who will ask. As for no white light during cockpit prep it could be difference in perception. Perhaps airbus wanted that way. It doesn't take long anyway.

[MD83FO]

Dear Vilas, I cannot find in the literature where it states that we must wait for refueling complete to begin the cockpit preparation. Thank you.

[vilas]

Dear Vilas, I cannot find in the literature where it states that we must wait for refueling complete to begin the cockpit preparation. Thank you.
My post #3 is a personal reply from Airbus.

[AerocatS2A]

My post #3 is a personal reply from Airbus.
In other words, it's not in the literature.

[Uplinker]

.....That is the reason why the recommendation to switch OFF the fuel pumps before refueling is not explicitly provided into the FCOM, because this recommendation is implicitly covers by SOPs in standard operations (i.e. when refueling is performed before the cockpit preparation)......

my bold.

Airbus SOPs are part of "the literature" surely?

Switching off fuel pumps on the ground while they could be running dry, seems to be a reasonable precaution to me. Heat and fuel vapour can be an explosive combination !

[AerocatS2A]

Well refuelling isn't usually performed before cockpit preparation where I work, and I can't see where it says it should be, not that that means it's not there of course. If it is important then the SOP should tie the pumps into the completion of fuelling.

[Check Airman]

At my company, if we waited for fuel to start our setup, we’d push late every time lol

[jettison valve]

Dear tdracer,
As was pointed out already, on A330/A340s (I think A380 is the same) the ENG master switch closes also the LP valve on the front spar. Unless... it´s assembled wrongly, as a hidden failure.
This lesson was learned when during a maintenance activity (for whatever reason!) an engine was to be shut down using just the ENG Fire P/B (which interestingly only moves the LP valve, but does not trigger the HMU or anything else in ATA 73). The engine kept on running for many minutes, when the engineers finally killed the engine with the ENG master switch.
Side facts: The incident took place on an A340 whose "operator" at that time was, well, a big aircraft manufacturer in Seattle. Secondly, we replicated the same scenario (eng shutdown via fire P/B) on a different airplane, and it took more than 60sec before the EGT started decreasing after P/B activation; I still wonder why it takes so long...
(Official documentation: https://ad.easa.europa.eu/ad/F-2003-360R1 - On reading the AD more than 15 years later, I am still amazed about the long compliance times set by the DGAC - for such a simple task, 12.000FH / 39 months (we pushed this through much quicker)).

Now, and the real reason to start typing: A big thank you for all your comments and insights! I really appreciate your contributions. No political nonsense or guesses, but always solid technical statements, presented understandibly, even for a maintenance person.

Thank you very much!
J. V.

[Denti]

Well refuelling isn't usually performed before cockpit preparation where I work, and I can't see where it says it should be, not that that means it's not there of course. If it is important then the SOP should tie the pumps into the completion of fuelling.
Really?

With a 25 minute turnaround, the fueller connects as soon as the doors are opened, and the flightdeck crew will start with the cockpit preparation as soon as they have finished the post-flight flows.

[AerocatS2A]

Really?

With a 25 minute turnaround, the fueller connects as soon as the doors are opened, and the flightdeck crew will start with the cockpit preparation as soon as they have finished the post-flight flows.
Yes? And once the cockpit preparation is finished the fueller is still hooked up. Look, sometimes they've finished but sometimes they haven't, there is nothing in our SOPs that ensures the fuelling has finished before the PF does the overhead panel.

[Jwscud]

There is nothing in our SOPs either.

There is howver plenty of “wise man’s guidance” from our training dept. My lot have a number of EIS1 old MSNs in the 1xxx range and I was strongly advised not to switch the pumps on until:
(a) refuelling was complete and
(b) the APU was running and the external power had been disconnected.

The reasoning behind the latter was experience showed most “challenging” problems (random ECAMs, CIDS issues requiring resets &c happened when switching power supplies with a high load. Not SOP or in the manuals but wise experience nonetheless!

[sonicbum]

Really?

With a 25 minute turnaround, the fueller connects as soon as the doors are opened, and the flightdeck crew will start with the cockpit preparation as soon as they have finished the post-flight flows.

You would be surprised to know there are airlines out there with much larger turn around times.

[vilas]

​Yes? And once the cockpit preparation is finished the fueller is still hooked up. Look, sometimes they've finished but sometimes they haven't, there is nothing in our SOPs that ensures the fuelling has finished before the PF does the overhead panel.​​​​​​ Going strictly by literature, it says during cockpit preparation no white light. So either put the fuel pumps on during refuelling or do the prep after refuelling. I am sure you are aware of the A320 incident where the crew taxied, took off and climbed to 370 when both engines flamed out and during dual engine flame out procedure they realized that the fuel pumps were off. They relit engines came back and landed.

[Check Airman]

Really?

With a 25 minute turnaround, the fueller connects as soon as the doors are opened, and the flightdeck crew will start with the cockpit preparation as soon as they have finished the post-flight flows.

How do you accomplish a 25 minute turn in an A320? The shortest I’ve seen is closer to 45 mins maybe.

[Cak]

It is possible to do it even faster :)
Some low costers have 25-30 min as standard turnaround time

[FlightDetent]

How do you accomplish a 25 minute turn in an A320? The shortest I’ve seen is closer to 45 mins maybe. 35 is the target for quite a large portion of the European ops. Doable, for anything below 30 in my personal experience the crew procedures become limiting.

Otherwise, the critical path is the cabin. Hence:
- remote parking, 2 sets of stairs
- deplane 5 minutes
- 10 min cleaning
- 5 min CC procedures, security check
- 10 min pax boarding
- 2 min head-count
- 3 minutes for engine start (IAE)

It is necessary for CC to be exactly on their marks for the above, needless to say it is the redcap who runs the show. The weakest link in my experience is the delay between cleaners leaving and first PAP stepping inside.

[Check Airman]

35 is the target for quite a large portion of the European ops. Doable, for anything below 30 in my personal experience the crew procedures become limiting.

Otherwise, the critical path is the cabin. Hence:
- remote parking, 2 sets of stairs
- deplane 5 minutes
- 10 min cleaning
- 5 min CC procedures, security check
- 10 min pax boarding
- 2 min head-count
- 3 minutes for engine start (IAE)

It is necessary for CC to be exactly on their marks for the above, needless to say it is the redcap who runs the show. The weakest link in my experience is the delay between cleaners leaving and first PAP stepping inside.

Impressive. Most of our outstations are planned for about a 1 hr turnaround. Rare to see under 50 minutes. If your day includes going through one of the hubs, 1.5 - 3 hrs is typical.

[AerocatS2A]

Going strictly by literature, it says during cockpit preparation no white light. So either put the fuel pumps on during refuelling or do the prep after refuelling. I am sure you are aware of the A320 incident where the crew taxied, took off and climbed to 370 when both engines flamed out and during dual engine flame out procedure they realized that the fuel pumps were off. They relit engines came back and landed.
That's what we do. We just do the cockpit prep, including fuel pumps, while the fuel is going on. All I'm saying is that if it is important that fuel pumps are left off until fuelling is complete then it is poorly communicated. Assuming that cockpit prep is done after fuelling is completed doesn't cut it.

[vilas]

Impressive. Most of our outstations are planned for about a 1 hr turnaround. Rare to see under 50 minutes. If your day includes going through one of the hubs, 1.5 - 3 hrs is typical.
Many Asian LCCs turn around in 25mts.

[Denti]

In a previous company where we still had aircraft cleaning we planned 45 minutes for an A321, and that was very much manageable. In a LCC world where there is no aircraft cleaning during turn around, just a short tidy by the cabin crew which includes the security check. Head count is not necessary, and thankfully engine start is a bit faster on the CFM, except the LEAP if you are unlucky enough to have a NEO.

[Check Airman]

Many Asian LCCs turn around in 25mts.

Gosh. I don't think I've ever done a 25 minute turn. Even when flying a regional jet.

[Check Airman]

In a previous company where we still had aircraft cleaning we planned 45 minutes for an A321, and that was very much manageable. In a LCC world where there is no aircraft cleaning during turn around, just a short tidy by the cabin crew which includes the security check. Head count is not necessary, and thankfully engine start is a bit faster on the CFM, except the LEAP if you are unlucky enough to have a NEO.

Interesting that a few replies here have mentioned engine start as part of the turnaround time. Why's that? Here, most companies measure the turn time from IN to OUT on the ACARS, so it'd be a few minutes between OUT and engine start.

[FlightDetent]

No jetty for the superquick ops. AOBT is the first movement.

In reality a flash turnaround can be achieved, even repeatedly. But maybe 30%? There would be a padding in the block-flight-block times, to allow some schedule recovery. With a PRM passenger everything goes to hell. Unless you are flying for one of the three strongest LoCos, where penalties on the ground service providers are dire. And everyone else needs to wait.

What was this thread about again? Oh that, shared 2 years ago I read the explanation with a bit of sadness.

[...] went to great lengths to wipe off the habit of leaving the pumps OFF, citing the no-white-lights rule. Now, 7 years later on the internet, I read that it does not apply to Fuel Pumps before refuelling ends? Yuck. And maybe that the AMM even specifies so!

Their logic that SOPs are well applied because during CKPT PREP the re-fuelling is finished is utter rubbish. That was NEVER true at any turn-around, since A320 day 1.

[AerocatS2A]

Interesting that a few replies here have mentioned engine start as part of the turnaround time. Why's that? Here, most companies measure the turn time from IN to OUT on the ACARS, so it'd be a few minutes between OUT and engine start.
Yeah, a push back is an extra 5 minutes leeway on the turn time.

[Check Airman]

Yeah, a push back is an extra 5 minutes leeway on the turn time.

I’m not really understanding this. I know that a lot of European airports use remote stands. Is this really factored into the turn times?

[Check Airman]

No jetty for the superquick ops. AOBT is the first movement.

In reality a flash turnaround can be achieved, even repeatedly. But maybe 30%? There would be a padding in the block-flight-block times, to allow some schedule recovery. With a PRM passenger everything goes to hell. Unless you are flying for one of the three strongest LoCos, where penalties on the ground service providers are dire. And everyone else needs to wait.

What was this thread about again? Oh that, shared 2 years ago

I’ve only deplaned via stairs a few times, but the turn time was always the same. If anything, the rear door is only usually opened for the cleaners to board.

[Denti]

I’m not really understanding this. I know that a lot of European airports use remote stands. Is this really factored into the turn times?

Well, yes and no. On a push back stand engine start up time doesn't factor as the engine is started during push back, after off block. However, on a taxi-out stand it does factor as the engine is started on stand and off block happens after that. Some airlines use a special "self maneuvering" delay code to track that.

I’ve only deplaned via stairs a few times, but the turn time was always the same. If anything, the rear door is only usually opened for the cleaners to board.

Even in a legacy carrier before i joined some LCCs we were happy to park on a remote stand, boarding and deboarding via two stairs is simply much faster than with just one entry. And yes, if possible, we always let the passengers deplane via both exits, it is nice for them and better for us.

[Check Airman]

Thanks for the clarification on the delay code. Never seen that tracked here. I quite like the stairs, if I’m being honest. Shame we don’t do it more- as long as the weather’s cooperating.

[FlightDetent]

Point being for below 30 min you pretty much need two stairs so there are no dual turnaround targets, rather the airline might selectively choose to use remote only. Also, failure of turning on time has financial implications for the GHA. Having a SLA that specifies turnaround extra of 5 mins = 300 EUR penalty is not unheard of. Then it's fair to allow 3 minutes for engine start, once things are getting Excel'd. If the Teutonic system come up with a dedicated delay code, nobody really is surprised.

[FlightDetent]

I quite like the stairs, if I’m being honest. Shame we don’t do it more- as long as the weather’s cooperating. Careful what you wish for. Imagine the cockpit load, more especially the lack of any lull to rev the brain down, if the target turnaround becomes 35 min. The GHA will learn how to match that so, day in and out, you'll be expected to make it too. Not to mention the possibility of 5 sector days.

[Denti]

Careful what you wish for. Imagine the cockpit load, more especially the lack of any lull to rev the brain down, if the target turnaround becomes 35 min. The GHA will learn how to match that so, day in and out, you'll be expected to make it too. Not to mention the possibility of 5 sector days.
Indeed, doing only minimum turnarounds can be very fatiguing. Especially for the PM (who does the walkaround where i work, but also the load calculation) it can be hard to get enough breathing time to visit the loo, especially when he is new to the operation.

So even if the working conditions are good, which they are at some outfits, although that might change now very fast, LCC flying is very hard work indeed, for both cabin crew and flight deck.

[AerocatS2A]

I’m not really understanding this. I know that a lot of European airports use remote stands. Is this really factored into the turn times?
It doesn't need to be factored in, but if you have a 35 minute turn around every time but some are push-backs and some are taxi-out, you effectively have an extra 4 - 5 minutes on the push back turn compared to the taxi-out turn. Where I currently work, every turn is a push back so it's a moot point, but I used to do freight with 35 minute turns and the little bit of extra time you got at the push-back ports made all the difference.

Indeed, doing only minimum turnarounds can be very fatiguing. Especially for the PM (who does the walkaround where i work, but also the load calculation) it can be hard to get enough breathing time to visit the loo, especially when he is new to the operation.

So even if the working conditions are good, which they are at some outfits, although that might change now very fast, LCC flying is very hard work indeed, for both cabin crew and flight deck.
To each, their own. Personally I'd much rather do a four sector day with minimum turn times rather than have a five to ten minute lull each time. Get to work, bang out the sectors, go home, that's my ideal work schedule.

[FlightDetent]

Depends on the routes. CDG-FRA-CDG-AMS-CDG-MAN (http://www.gcmap.com/mapui?P=CDG-FRA-CDG-AMS-CDG-MAN) (or similar) those extra 5 minutes on the ground do make a lot of difference. For SOF-STR-SOF-KBP-SOF (http://www.gcmap.com/mapui?P=SOF-STR-SOF-KBP-SOF), hell yes why not keep one engine running.

[Uplinker]

Re cockpit preparation; we used to do everything else, but we would leave the fuel pumps off.

Just before PF called for the Before Start checklist, they would double check the overhead panel for any white lights and put the pumps on then. And start the APU as well, if it had not been started already.

Can't remember if this was our Airline SOPs or just something we did.

[Denti]

To each, their own. Personally I'd much rather do a four sector day with minimum turn times rather than have a five to ten minute lull each time. Get to work, bang out the sectors, go home, that's my ideal work schedule.

Absolutely, i rather do four short domestic sectors than a 5 hour out and back day. Even better if they switch to just two short domestic sectors ;)


Re cockpit preparation; we used to do everything else, but we would leave the fuel pumps off.

Just before PF called for the Before Start checklist, they would double check the overhead panel for any white lights and put the pumps on then. And start the APU as well, if it had not been started already.

Can't remember if this was our Airline SOPs or just something we did.

Sounds sensible.

[Check Airman]

Thanks guys. Really eye opening. Very different operating culture on this side of the Atlantic. We’re not usually as concerned about departure time- then again the cockpit crew isn’t usually the time limiting factor in our turns.

[FlightDetent]

Really eye opening. Very different operating culture on this side of the Atlantic. I'd bet you won't find an aspect of the job we did not manage to make less rewarding or more demanding.

[Check Airman]

I'd bet you won't find an aspect of the job we did not manage to make less rewarding or more demanding.

I wouldn't say that. It's my understanding that you guys don't usually do overnights on narrowbodies. I find that very appealing. At most airlines in the US, that kind of flying is very senior. Many people will bypass upgrading to captain or larger airplane in order to enjoy being home every night.

I also think commuting is less prevalent across the ocean. That's immensely stressful.

[sonicbum]

I wouldn't say that. It's my understanding that you guys don't usually do overnights on narrowbodies. I find that very appealing. At most airlines in the US, that kind of flying is very senior. Many people will bypass upgrading to captain or larger airplane in order to enjoy being home every night.

I also think commuting is less prevalent across the ocean. That's immensely stressful.

We do at Legacies ; rosters are pretty much always 3 to 5 days trips on short - medium haul and the same (obviously) on long haul. LCC's have a different business model with a multi base scheme, that is why they rarely go on layover.

[Denti]

I wouldn't say that. It's my understanding that you guys don't usually do overnights on narrowbodies. I find that very appealing. At most airlines in the US, that kind of flying is very senior. Many people will bypass upgrading to captain or larger airplane in order to enjoy being home every night.

I also think commuting is less prevalent across the ocean. That's immensely stressful.

It depends. As sonicbum has mentioned it is quite common in legacy carriers to be on the road for a few days, between 2 and 6 on narrowbodies and up to 15 days on widebodies. But yes, LCCs usually have a multibase strategy and try to plan without layovers as much as possible. And i honestly didn't know the difference until i switched from legacy to lcc. Now i jump on my bike, cycle to the airport, fly a few hours, cycle back and enjoy my own life at home. Whereas before i always had to pack my suitcase, get it to the airport, sleep in horrible hotels if sleeping is possible at all and usually do a shift pattern change during every rotation (early to late or late to early). Of course a fixed roster pattern, which is quite common in LCCs, does help a lot too for quality of life. The difference is of course hub based traffic vs pure point to point connections.

Commuting is not as easy on this side of the atlantic. That said, it is still done a lot. However, as many options include paying for the fun of it there is not only the loss in quality of life to consider, but also the financial implications that effectively reduce your take home pay, even if it is tax deductible.

[Dave Therhino]

Dear tdracer,
As was pointed out already, on A330/A340s (I think A380 is the same) the ENG master switch closes also the LP valve on the front spar. Unless... it´s assembled wrongly, as a hidden failure.
This lesson was learned when during a maintenance activity (for whatever reason!) an engine was to be shut down using just the ENG Fire P/B (which interestingly only moves the LP valve, but does not trigger the HMU or anything else in ATA 73). The engine kept on running for many minutes, when the engineers finally killed the engine with the ENG master switch.
Side facts: The incident took place on an A340 whose "operator" at that time was, well, a big aircraft manufacturer in Seattle. Secondly, we replicated the same scenario (eng shutdown via fire P/B) on a different airplane, and it took more than 60sec before the EGT started decreasing after P/B activation; I still wonder why it takes so long...

J. V.


It takes about a minute of idle operation for the engine to flame out after closing the spar valve or LP fuel valve only (not the HP valve in the engine HMU) because that's how long it takes to suck the remaining fuel out of the fuel line between the LP valve on the rear spar and the fuel pump to the point where LP stage of the fuel pump receives excessive vapor and sends vapor to the HP pump. It takes a similar amount of time on the Boeing airplanes.

[jettison valve]

It takes about a minute of idle operation for the engine to flame out after closing the spar valve or LP fuel valve only (not the HP valve in the engine HMU) because that's how long it takes to suck the remaining fuel out of the fuel line between the LP valve on the rear spar and the fuel pump to the point where LP stage of the fuel pump receives excessive vapor and sends vapor to the HP pump. It takes a similar amount of time on the Boeing airplanes.

Hi Dave,
I agree as to where the fuel comes from - but my real question is: What "replaces" this fuel, in other words: what happens to the space where the fuel is taken from by the engine?
Assuming that the LP valve and the tubing between the LP valve and the HMU has no leaks, there would be a SIGNIFICANT vacuum in the lines...? Wouldn´t that trigger leaks afterwards as the tubes are designed for "outward" pressure, not an internal vacuum?
Regards, J. V.

[tdracer]

Hi Dave,
I agree as to where the fuel comes from - but my real question is: What "replaces" this fuel, in other words: what happens to the space where the fuel is taken from by the engine?
Assuming that the LP valve and the tubing between the LP valve and the HMU has no leaks, there would be a SIGNIFICANT vacuum in the lines...? Wouldn´t that trigger leaks afterwards as the tubes are designed for "outward" pressure, not an internal vacuum?
Regards, J. V.
With the spar valve closed, the main engine fuel pump is basically doing a 'suction feed' of what's in the pipe downstream of the spar valve. So what's filling in the extra space is fuel vapor - in a sense the fuel in the line starts to boil due to the suction of the fuel pump. Eventually the fuel pump cavitates and can't provide sufficient fuel pressure to keep the engine running and it quits. A minute for that to happen is pretty average - although it can go anywhere from about 30 seconds to two minutes depending on the volume of the pipe and the idle fuel flow of the engine.
Oh, and thanks for the kind words.
BTW, I'm a bit surprised that no one has mentioned the possibility of running a fuel pump in an empty tank as a reason to shutdown the fuel pumps. If the fuel tank is nearly empty, and the fuel pumps are merrily running with no fuel actually being pumped, it's possible for the fuel pump to overheat. Now, the fuel pumps are designed not to overheat in that scenario, but just like anything else fuel pumps wear and deteriorate - and have been known to fail in such a way that they do overheat to the point that they become a potential ignition source.
No idea of that's part of the Airbus thinking, but I do know that's why - at least on Boeing's - you're instructed to turn off the center tank fuel pumps as soon as the tank is nearly empty and you get the low pump pressure indications.

[FlightDetent]

Center tanks pumps switch off too on AB without fuel. more explicitly they won't engage in an empty tank.

The issue of the thread is reading the AB FCOM which instructs pilots to turn the fuel pumps on, during cockpit prep, without telling them this is only to be done after the refuelling.

[Connie Wings]

Dear mates,
Just a quick chat, please, do you know if the Red Beacon Lights are required to be turned ON during walkaround procedures?
My question is that this light could halt ground personal around aircraft safe area.

[Check Airman]

Never noticed any operator employ this SOP. At my old airline, they wouldn’t approach the plane until the beacon was off. (current airline- they’ll have the cargo door open before you even get a chance to reach for the beacon :ugh:)

[FlightDetent]

Dear mates,
Just a quick chat, please, do you know if the Red Beacon Lights are required to be turned ON during walkaround procedures?
My question is that this light could halt ground personal around aircraft safe area. More worryingly, this could teach the ground personnel to ignore the beacon light.

The logical question how do we check the beacon has a simple answer: the engineers would on a daily basis. Should it break mid-day, the redcap is sure to tell you and MMEL relief is available.

That itself is a good marker if you really need to verify its operation as a pilot before each flight. Items dispatchable i.a.w. MMEL are those, where another independent failure on the same system won't directly jeopardise the safe outcome. I.e. systems you can afford to lose with 2 levels of protection then remaining.

Simply put, for MMELable items it is OK to wait until they fail, no need to verify beforehand. As a general concept.

​​​​

[Connie Wings]

More worryingly, this could teach the ground personnel to ignore the beacon light.

The logical question how do we check the beacon has a simple answer: the engineers would on a daily basis. Should it break mid-day, the redcap is sure to tell you and MMEL relief is available.

That itself is a good marker if you really need to verify its operation as a pilot before each flight. Items dispatchable i.a.w. MMEL are those, where another independent failure on the same system won't directly jeopardise the safe outcome. I.e. systems you can afford to lose with 2 levels of protection then remaining.

Simply put, for MMELable items it is OK to wait until they fail, no need to verify beforehand. As a general concept.

​​​​
Thanks, FlightDetent. My question was not so clear.
What I was trying to bring to chat is just that: - If Red Beacon lights need to be "ON" during external lights check.
I agree to your answer.

[sonicbum]

Thanks, FlightDetent. My question was not so clear.
What I was trying to bring to chat is just that: - If Red Beacon lights need to be "ON" during external lights check.
I agree to your answer.

No, it is a maintenance task to check both upper and lower beacon lights. During the external walkaround You check on the lower center fuselage that the beacon light is in place and not damaged.

[Connie Wings]

No, it is a maintenance task to check both upper and lower beacon lights. During the external walkaround You check on the lower center fuselage that the beacon light is in place and not damaged.

Appreciate chat, Sonicbum.
My conclusion is that, even though some commercial airlines require external lights check during walk around, totally agree that red beacon and strobe lights should be checked by maintenance or, red cap shall tell us if it's not working.

Many Thanks

[screwdriver]

There is nothing in our SOPs either.

There is howver plenty of “wise man’s guidance” from our training dept. My lot have a number of EIS1 old MSNs in the 1xxx range and I was strongly advised not to switch the pumps on until:
(a) refuelling was complete and
(b) the APU was running and the external power had been disconnected.

The reasoning behind the latter was experience showed most “challenging” problems (random ECAMs, CIDS issues requiring resets &c happened when switching power supplies with a high load. Not SOP or in the manuals but wise experience nonetheless!
Probably applicable to very old MSNs. However, the reasons for doing this are no longer applicable

[screwdriver]

Re cockpit preparation; we used to do everything else, but we would leave the fuel pumps off.

Just before PF called for the Before Start checklist, they would double check the overhead panel for any white lights and put the pumps on then. And start the APU as well, if it had not been started already.

Can't remember if this was our Airline SOPs or just something we did.
Big Airways pilots did a combination of both. It was clarified a few years ago. White lights out on preparation.

[Jwscud]

We still fly 10xx MSNs quite regularly.

Old ships we encounter includes one with the legacy electrical systems and plenty with the “old” alternate brakes and NWS off the Green HYD.