A320- Apu bleed & WAI

[Wilstar]

Hello,
does anyone knows why, in the pneumatic system of the A320, the pneumatic duct of the APU bleed comunicates with the duct of engine bleed for Wings Anti Ice?
To use APU bleed for WAI is not permitted by the SOP, then why link this circuit to the one of WAI?





(Sorry for my english:))

[Goldenrivett]

To use APU bleed for WAI is not permitted by the SOP
The APU bleed is much cooler than the engine bleed system, and would be ineffective for WAI.

[TSIO540]

The two systems are plumbed together because:

APU bleed air needs access to the crossbleed duct to reach the starter for each engine;and

The Wing Anti-ice system needs access to the crossbleed duct for symmetrical anti-icing on one engine.

This arrangement eliminates the need for a separate APU bleed line to each engine starter.

The BMC takes care of switching logic depending on overhead panel selections and whether engines or APU are running.

The pilot must take care not to use APU for WAI as it's a limitation in the FCOM (not hot enough) and also to select one pack off for single engine WAI 'on' operations (status page & FCOM).

[Wilstar]

Tahk you very much, all is clear!!:ok: