787 Electric Airframe Anti Ice

[alexguru]

Does anyone know how unservicabilities are dealt with as related to MEL? Is the failure mode "fail on" as with engine anti-ice? I was told the airplane could be dispatched with the system inop.

[sleeve of wizard]

MEL 30-11-01 Wing Ice Protection System
interval C
Installed 1
required 0

May be inoperative provided the aircraft is not operated in known or forecast icing conditions.
ETOPS is not conducted.

[alexguru]

Thanks! Interesting to understand how viable the restrictions are for normal operation. I understand reliability is fairly high.

[stilton]

PS it's not 'airframe' anti-ice.


That would take a bit more power.

[STBYRUD]

Thats pretty darn restrictive as it is... "not operated in known or forecast icing conditions" is virtually undispatcheable depending on where you are based

[tdracer]

"May be inoperative provided the aircraft is not operated in known or forecast icing conditions" are pretty standard MEL words for any ice protection system - engine/cowl or wing.
How restrictive that is depends on the season - often not a big deal during the summer but can be AOG in the winter .
I've not seen numbers for the 787 wing system, but at least in theory electrical systems are more reliable because there are fewer moving parts (the most common failure for pneumatic anti-ice is a failed valve).