B737NG - Wing Anti ICE

[B737NG_Pilot]

Positioning the WING ANTI–ICE switch to ON in flight:

Sets stall warning logic for icing conditions.

Stall warning logic remains set for icing conditions for the remainder of the flight, regardless of subsequent WING ANTI–ICE switch position.


What is the logic behind this? Why can't it revert back.

[shlittlenellie]

Because wing anti-ice activation has only cleared ice from the leading edge and not the entire wing. If ice has formed on the leading edge then it's entirely possible that there's ice on the wing elsewhere that has not been cleared. Conservatively accounting for ice in the stall logic for the remainder of the flight is sensible.

[RAT 5]

Possibly also on the unheated tail surfaces.

[B737NG_Pilot]

Thank you shlittlenellie and RAT 5.. now it makes sense.

[flyingchanges]

Because only about 1/2 the wing is protected.

[de facto]

Because only about 1/2 the wing is protected.


What aircraft do you fly?

Stall warning logic remains set for icing conditions for the remainder of the flight, regardless of subsequent WING ANTI–ICE switch position.

Same logic as a loss of of climb gradient if flight in icing condition and landing at oat<10C.

[cosmo kramer]

Systems knowledge defacto, systems knowledge. It recurrent by you that you jump someone's throats without having "da facts" straight:
The wing anti–ice system provides protection for the three inboard leading edge slats by using bleed air. The wing anti–ice system does not include the leading edge flaps or the outboard leading edge slats.
I.e., only approx half the wing is protected.

[de facto]

Oh my Kramer...
My question was not sarcastic but genuine,i had in mind(mental picture) half wing (root to half wing) not deiced and half wing to end as deiced or vice versa.

It would seem you are quick jumping my throat:rolleyes:

[flyboyike]

Oh please, who cares about having one's facts straight around here?

[BOAC]

Systems knowledge defacto, systems knowledge. - in fact, ck, some would say 'read the FCOM':)