737NG EAI & WAI operation

[Jack1985]

Hi, I'm just wondering what are the procedures relating to Engine Anti Ice and Wing Anti Ice. I'm particularly interested in its operation with Boeing 737NG models. I understand that they are not turned on above 10°c. I'm just wondering would they be turned on if the temperature drops below this for all stages of the flight until the temperature goes back above 10°c? Thanks for your help! :)

[ImbracableCrunk]

TAI (engine)

Quick & Dirty:
Visible moisture and:
Ground ops and Climb, TAT/OAT +10C = ON
Climb and Cruise, SAT drops to -40C = OFF
Descent and Ground ops, TAT/OAT +10C = ON
Greater than +10C, OFF
No moisture, OFF

[despegue]

Below SAT -40 but with thunderstorms in vicinity: ON

[RAT 5]

Below SAT -40 but with thunderstorms in vicinity: ON

Is that personal opinion or manufacturer's? Define vicinity if VMC.

Here's a common sense question reading between the lines. SAT >-40c, but you are IMC in descent, BUT you are doing V/S 1000fpm with >70% N1% thrust. EAI ON/OFF? You are in CRZ medium level >-40c: N1% >70% EAI OFF SOP. So what's the difference? I suspect the EAI ON in descent even when >-40c is the expectation to being doing an idle power descent with only FLT Idle for protection. What do you do in the 1st scenario?

[despegue]

Rat5,

Personal in IMC and with CB or TS reported, especially in the ITCZ.

Not a manufacturer mandated procedure, neither is it SOP.

[Jack1985]

Interesting, Thanks! :)