Anti-ice usage
With reference to usage of Engine Anti-ice usage on the B737NG
Engine anti-ice must be used if in icing or anticipated icing conditions during CLB & CRZ until temp drops below -40degrees celcius. Exceptions to this ofcourse is on the descent, where it is to be used even if below -40.
Is this -40degrees(for CRZ & CLB) like a definitive(or conservative) figure? does this mean that the engine WILL NOT pick up any icing at temperatures below -40?
Personally, I have noticed mild ice on the wiper blades below this temperature
What criteria does everyone else use?
Thanks