+10 C
So, what happens to temperature when pressure is reduced?
So, what kind of pressure are we talking about in front of the engines?
The rule is +10 or less...visibile moisture...taxiing over moisture...visibility one statute mile or less, etc., etc.
Further, when temperatures are BELOW -40 (SAT) in climb or cruise...anti-ice is not needed >>>>EXCEPT<<<< when operating in the vicinity of TRW (where supercooled water droplets can and do exist)...then, engine anit-ice ON even if the SAT is less than -40.
I used to fly with a fellow...nice guy and a good pilot...but he was misinformed about the use of engine anti-ice. We'd be flying along and ice would be building up under the windshield wiper blades. He wouldn't turn on the engine anti-ice...he said that ice would form under the wiper blades first because of it being a low pressure area.
Well, yes, that's true....BUT, IT'S A LOW PRESSURE AREA IN FRONT OF THE ENGINES TOO!!!!!!
Airbus has got a great briefing bulletin (Briefing Notes, I think they call it.) about the topic of operations at high altitudes (i.e. SATs below -40c) and thunderstorm flying. Seems that many guys have been thinking that, if the SAT is colder than -40c, the engine anti-ice need not be activated.
And, engines have been flaming out...damaged, etc.
Fly safe....
PantLoad