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Eurotraveller
31st Jan 2010, 21:26
Hi there,

Just wondered if anyone would be kind enough to help me out with a couple of questions on the A320 Gravity Fuel Feeding procedure in the case of L(R) TK PUMP 1 + 2 LO PR (and Centre Tank Empty).

1.
FCOM 3.02.28.1 states, "When TK (affected) FUEL RQRD: - TK (affected) FEED GRAVITY ONLY". It also has a note, "Apply Gravity Fuel Feeding Procedure...Fuel from the affected tank may be used immediately, if there is no ceiling limitation for gravity fuel feeding".

Elsewhere on that page, initial actions for dual pump failure with centre tank empty are listed as "Fuel X-Feed (if above FL150)...ON". I understand that this is to allow fuel from the offside tank to feed the engine with the failed pumps initially before beginning the gravity feed procedure, in case you need to descend to the gravity feed ceiling.

If dual pump failure were to happen say at FL340 having been in the cruise for 2 hours, the Gravity Feed Ceiling is the current FL according to the QRH 2.09. Is there any need to follow the initial actions and put the Fuel X-Feed on in this instance? As I read the FCOM you can simply turn the failed pumps off and allow gravity feeding to begin, as "there is no ceiling limitation" to worry about. Are there any actions at all in this case other than turning the failed pumps off?

2.
Is there a lower altitude limit for gravity feeding? I note from FCOM 3.02.28.2 that "When reaching FL150 Fuel L(R) TK PUMP 1+2 LO PR" warning is recalled automatically, but I can't see a lower limit specified anywhere in the FCOMs, unless I'm missing it...

Thanks in advance,
Eurotraveller

TyroPicard
1st Feb 2010, 18:31
Remembering that first you follow ECAM then read FCOM 3 if time.. you won't read all those notes until "ECAM ACTIONS COMPLETE".
If dual pump failure were to happen say at FL340 having been in the cruise for 2 hours, the Gravity Feed Ceiling is the current FL according to the QRH 2.09. Is there any need to follow the initial actions and put the Fuel X-Feed on in this instance?Short answer .. YES, because ECAM tells you to. This is safe and covers all possible scenarios. When you read STATUS you do the GRVTY FUEL FEEDING procedure from the QRH and discover that FL 340 is OK - you can then turn OFF the FUEL X-FEED.

As I read the FCOM you can simply turn the failed pumps off and allow gravity feeding to begin, as "there is no ceiling limitation" to worry about. Are there any actions at all in this case other than turning the failed pumps off?See answer above. You are technically correct but that's not the way we do it. ECAM protects the engine fuel feed while you take your time and delve into the books.

Is there a lower altitude limit for gravity feeding?Not that I am aware of - but there may be a higher one - 7,000ft above takeoff airport.

Eurotraveller
1st Feb 2010, 18:38
TyroPicard - many thanks for your help.

Eurotraveller