A320 center tank pumps at "Engine Start"

[tolosan]

Hello,

referring to the diagram FCOM DSC 28-10-30 p3, with fuel in the center tank,

how do you understand " 2 min AFTER ENG START " ?

For each center tank pump, do the two minutes start when their related master engine switch is set to ON position ? In that case, it would mean that engine start is done with fuel from the center tank.

Or

Later ?

[gAMbl3]

As per Technical Training Manual :

"During the engine start sequence and in the following 2 minutes, the center tank pumps run regardless of the slat position. When running, center tank pumps have priority for engine supply over wing tank pumps. After this delay, center tank pumps stop because slats are still extended."

[tolosan]

Thanks gAMbl3, it's a lot clearer than the FCOM.

Can you confirm when the eng start sequence ends according to your manual ?

[cosmiccomet]

The starting sequence is ended when the grey background on the N2 indication disappears.
PRO-NOR-SOP-08 P2/4

[tolosan]

Yes and stated in DSC-70-90 :

(6) HP rotor speed N2 The numbers are normally green. (During start sequence, they are green on a grey background).

[Jetdriver_JAT]

In any case, when the ECAM Memo appears the test of the centertank pumps is completed, and the 2 minutes have passed :ok:

DSC-31-15 P 5/8

[Cardinal]

The starting sequence is ended when the grey background on the N2 indication disappears.

Indeed, but the time related items (2:00 center tank feeding, 0:30 pack valves) count forward from the start valve closing @ 50% N2.

[tolosan]

Hello Cardinal,

For the pack flow control valve, the FCOM is clear but nothing is mentioned for the center tank pumps.

What is your airbus reference for the 50% N2 as time check for the two minutes ?