A330 / why is there one Wing Anti-ice P/B SW and two Eng' Anti-ice P/B SW??

[Juuuune]

what is different about Switch?

A330-200/300

why is there engine anti-ice P/B sw is two and Wing anti-ice P/B sw is one.

I think engine thrust? or engine asymmetry?

plz tell me why its different

[TURIN]

Under MEL we can deactivate engine anti ice on one or both engines.
Air frame anti ice can not be deactivated assymmetrically. It's either all on or all off.

[blind pew]

Probably three separate systems as on the kit I flew

[Uplinker]

No time to go and check the books, but I think that if you had one engine out, you would not want to use hot air from the other engine(s) to anti-ice that dead engine*. That would be a waste of power, which would not be desirable with one engine out.

But obviously you would never want to anti-ice only one wing !

*do engines only anti-ice themselves or does each engine contribute to anti-icing all engines ? Can't remember.

[TURIN]

I think Eng anti ice is only from the onside engine. Usually a separate bleed off the compressor.
EG 787 does not use bleed air for air conditioning but it does have a single bleed for engine antice.

[sonicbum]

Originally Posted by Uplinker

No time to go and check the books, but I think that if you had one engine out, you would not want to use hot air from the other engine(s) to anti-ice that dead engine*. That would be a waste of power, which would not be desirable with one engine out.

But obviously you would never want to anti-ice only one wing !

*do engines only anti-ice themselves or does each engine contribute to anti-icing all engines ? Can't remember.

CEO
👇
An independent air bleed from the high pressure compressor protects each engine nacelle from ice. Air is supplied through a two-position (open and closed) valve that the flight crew controls with two pushbuttons, one for each engine.

Each engine on his own.

[Jonty]

And there’s only one for the Wing Anti Ice because you would never want to deice only one wing!

[Juuuune]

Originally Posted by TURIN

I think Eng anti ice is only from the onside engine. Usually a separate bleed off the compressor.
EG 787 does not use bleed air for air conditioning but it does have a single bleed for engine antice.

I mean why Wing anti-ice P/B is not two?

If Engine anti-ice P/B is one, each engine bleed air(e.g. Trent 700 HPC 3th) can supply own enging lip skin.

I think its has another reason.. about.. engine thrust... or something

[Juuuune]

I mean why Wing anti-ice P/B is not two?

If Engine anti-ice P/B is one, each engine bleed air(e.g. Trent 700 HPC 3th) can supply own enging lip skin.

I think its has another reason.. about.. engine thrust... or something

[Check Airman]

The rationale is that you’re better off having a bit of ice on symmetrically on both wings than asymmetrical icing levels.

[tdracer]

Engine to engine isolation is a regulatory requirement, so you don't want a single failure (e.g. the engine anti-ice switch) to affect both engines. And the EAI systems are completely independent for each engine - no common ties.
Wing Anti-Ice is a single system - and as others have mentioned you would not want to have asymmetric wing icing - better to have it all off than to have it off on one side.

[Uplinker]

There is no need for two wing anti-ice P/Bs, because you would NEVER want - or need - to anti-ice just one wing and not the other

So there is simply no need for two switches, which would only add needless complication and no advantage whatsoever.

Having two wing anti-ice switches could also cause a serious problem if both wing anti-ice switches were pushed but only one actually stayed in, and this was not noticed until one wing stalled. Or if one switch became faulty.

You really don't want asymmetric lift.

[Amadis of Gaul]

Originally Posted by Uplinker

*do engines only anti-ice themselves or does each engine contribute to anti-icing all engines ? Can't remember.

Wow, that's a good one.

[tdracer]

Originally Posted by Uplinker

*do engines only anti-ice themselves or does each engine contribute to anti-icing all engines ? Can't remember.

I can't speak for all installations, but on the ones I'm familiar with, the EAI is engine specific - it doesn't come off the aircraft bleed system. The EAI bleed air actually comes off the engine bleed system.