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Luc47
7th Feb 2017, 17:09
1 - We turn fuels pumps off during a transit stop to turn them back on again. I can not find any reason for that. Do you do the same ? Is it some sort of reset?
2 - it says in our FCTM that flying with AP off and ATHR on, it is strongly recommended to have FD's off. But the phrase is not clear. Do they mean that if you set one FD off then make sure that both are off or that one should not fly with FD's and ATHR on when AP is off ?
Thank you in advance for you answers!

FlyingStone
7th Feb 2017, 17:19
1. Why run pumps for an hour if you don't need them? That being said, some operators do leave them on during short turnarounds.

2. Read the FCTM carefully, it gives you a reason why one shouldn't use only one FD on in A320 - to keep the A/THR in SPEED mode, when flying manually. Either both ON and follow them, or both OFF.

Amadis of Gaul
7th Feb 2017, 17:25
Concur on both counts.

vilas
8th Feb 2017, 07:04
Luc47
About fuel pumps off following is airbus reply:


At the end of the flight, Airbus SOP (Refer to FCOM-PRO-NOR-SOP-22 P2/4) requests the flight crew to set FUEL PUMPS to OFF

- During the cockpit preparation, Airbus SOP (Refer toFCOM-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 potentiallyabort refueling process). That is the reason why the recommendation to switch OFFthe 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.

PilotJames
8th Feb 2017, 11:33
I've often wondered the official Airbus answer. Did you ask them directly on tech request Vilas?

Black Pudding
8th Feb 2017, 13:59
Whilst we are on the subject of fuel pumps, does anyone have any information to back up if having the fuel pumps on during ground time increases the fuel temp. Every summer here in the Middle East, we have problems with high fuel temp advisory.

vilas
8th Feb 2017, 17:16
PilotJames
Yes! I did.

pfvspnf
8th Feb 2017, 20:54
My SOP states all white lights out even during refuelling.

Could you please provide me the reference for recommendation of having the pumps off to avoid dry running?

And absolutely concur with the other point both FDs off to ensure athr in speed mode, or Both FDs ON

Fokkerdriver
8th Feb 2017, 21:19
There was an OEB a few years ago telling Airbus drivers to turn the center tank pumps OFF.

Now our manual states it is to avoid low pressure warnings.

Otherwise check out EASA airworthiness directive AD No.: 2007-0218R2

2. Never turn just one FD OFF on the bus!

fruitloop
8th Feb 2017, 22:27
What Fokkerdriver said...

Feather44
10th Feb 2017, 22:15
does anyone have any information to back up if having the fuel pumps on during ground time increases the fuel temp. Every summer here in the Middle East, we have problems with high fuel temp advisory.

I heard the same. True or not??

Willie Nelson
11th Feb 2017, 02:52
Luc47,

Vilas answered question 1 pretty comprehensively as he is apt to do. Can you give us the reference for your second question, I am not aware of such a restriction.

Having -FD2 or 1FD- is a recipe for a disaster such as this:

https://en.m.wikipedia.org/wiki/Indian_Airlines_Flight_605 (and other alpha floor incidents world wide to say the least)

But it would appear that that is not your question. There is no such recommendation in my manuals that are very much aligned with Airbus.

Perhaps what you have there is simply a recommendation as to how your company would like you to practice your hand flying should you wish to do so, but that would certainly not be an Airbus standard requirement.

vilas
11th Feb 2017, 08:16
FDs should be switched off when you don't intend to follow them. On approach during final descent use of OP DES/DES is not recommended because thrust will be idle. That is why during visual approach both FDs are to be switched off to get ATHR in speed mode. ATHR may be used in manual but still the FDs are to be kept off.