3 crossbleed valves on A380

[WhiteKnight]

Hello,

I don't understand why we need 3 crossbleed valves on the A380. Let's say we have a bleed leak on engine 1. The onside (left) and the center crossbleed valves closes and the right crossbleed valve opens. This interconnects bleed system 3 and 4. Why does it do that?

Or another example: We get bleed leak on one of the inner engines. For example engine 3. In this case the left and center crossbleed valve opens the right one stays closed and bleed system 1,2,4 are getting interconnected.
Again, I don't understand the logic behind this switching.

Can anyone help? Much appreciated.

Thank you very much!

[helen-damnation]

A bit of theorising but..

Engine 1/outer wing leak - centre closed because you can't use APU bleed and onside closed to avoid cross contamination to the pack or feeding the wing leak.

Eng 3/inner wing leak - right closed to avoid the cross contamination and centre open to allow use of APU bleed if required.

Looks like the L/R opening allows for Pack Bay Vent and Hyd Rsvr Press as well.

"When an engine or a wing bleed duct is affected, the applicable bleed source is closed, and the crossbleed valves are closed, as appropriate."

Happy to be corrected, always learning :O