A320 FUEL PUMP
 

why we should turn the six fuel pumps off when we are refueling on the ground,if we are not turn them off ,what is the dangerous of it ?

turning OFF the fuel pumps during refueling is NOT Airbus procedure.

of course I have an idea why some airlines do it. but if your airline does that, just better ask your airline.

Some Airbus models have a refueling manifold drain valve in the inboard tanks which drains the manifold when opened by inboard boost pump pressure - if these pumps are on when refueling, fuel will go into the inboard tanks uncontrolled by the refueling system and could result in incorrect fueling. Possibly this is the reason for pumps to be selected off while refueling.

there are actually more info in the AMM.

my point is, it is not in the FCOM, ergo...

Inboard pumps as mentioned above; all pumps to reduce electrical load and transients on switchover from external to APU generator.

Also helps get a smidgin more air from the APU when trying to cool the cabin in blistering temperatures, or the old-fashioned cost saving by loading the APU generator less.

We operate mixed fleet of A319/320/321. However, only for the two A320s (low MSN) do we switch off the centre tank pumps for refuelling. Anyone know why?

Hi Superpilot,

About 6 years ago there was notice about the center tank pumps running during refueling despite the tanks being empty (dry sensor). The pumps would then become "un primed" which meant they were unable scavenge the center tank dry. This eventually resulted in carrying about 200 kgs of fuel in the center tank which was unuseable. (If the center tank was then fueled with 500 kgs, the pumps would "prime" and all the fuel could be scavenged).

Until the new logic for center tank pumps is fitted, we still turn the center tank pumps off during refueling.

Thank you very much