Why we have to use ANTI ICE Below 10 degree
 

Is there any special reason
Why we have to turn on the anti ice sw on below 10 degree not minus degree?

Venturi effect in the inlet cold the entering air to 0C, so SAT of +10 might equal freezing conditions.

This is pretty basic stuff for a professional

GF

Some of the most horrendous icing I've seen has been between 0 and +10C. As galaxy flyer said, basic stuff.

10 degrees, but measured how?

On the Douglas/Boeing 717 it's 6 degrees, C, TAT. Even with an indicated TAT of up to 20C, I've seen quite large ice accumulation on th wiper arms & blades. A check of the OAT even at +20 TAT or more, can reveal sub zero temps.

Yup, obviously 10° is TAT, not SAT! The temperature rise resulting from airspeed will obviously not be the same everywhere on the aircraft, but the indicated TAT should in principle be the highest apparent temperature anywhere on the plane, but local effects can of course mean that the actual temperature around ice critical parts is much lower.

Icing range: +10 TAT to -40 SAT.

The numbers mean nothing without the SAT/TAT detail.

I think the point is whether the situation leads to Ice stick to engine inlets or not. Ice accumulation on windows doesnt necessarily shows hazardous Icing condition.

This is an extremely fundamental question. I sincerely hope that idisaid is not a professional pilot.

If the OP is already a pilot, why do they not know the answer to this question???????

Why was it not covered in their training??? How did they pass their exams?????

This really scares me.

Ah, the perfect people are having a go...

So you passed all exams ever with 100%....? If not, I´m "scared"...

Many years ago we faced this same question throughout the industry, pilots, operators and manufacturers. So we brought in some science and to be sure we got the word across we all agreed to the same guideline to avoid confusing pilots switching from one aircraft to the next.

I'm happy to see from the discussion above that it's under control and in the general knowledge bank. I see no harm in questioning the issue as long as one follows the guideline at the same time.

Is that a dig at me dudeness? :D

Interesting. If the OP is a qualified pilot, do you really think it is OK that they do not know such a fundamental fact as the physics and temperature range of icing?

Guys,

Maybe he was asking about ground use of TAI?

Flying turboprops many years back,the aircraft was fitted with a TAT kinetic heating chart.
Basically at 250 kts,a TAT of 10c would give SAT of O degrees C.

Also on the ground,there is a drop of temperature as ambient air is sucked into the engine,i believe there was a discussion whether +5 c would be a more sensible restriction as the drop in temp was around 3c.,but no news.
The same for the WAI,should be used for example at less than 10c in visible moisture.(vis 1500m or less,rain..).
In any case,follow your aircraft AFM guidance.

No, they were born knowing everything.

They never had to ask questions, they never had to be told anything;)

Yes uplinker that was mostly 'for you'.

You conclude something from basically one sentence and don´t know the context (or complete picture) - and the OP is likely a Korean, which means there could be a 'language thingy' lurking in the dark as well...

Sometimes even the most fundamental things are not obvious. Thats how the human brain works - ask the pilots of AF447 as one example....57 times the airplane told them "Hey guys I´m stalling" and still they asked "whats happening here"...

And turning your argument around, we should all have to pass at 100% and all imaginable questions should be asked. Cause, If you not know something, it might be dangerous and thus "scary". :ugh:

Even IF the OP has a 'knowledge gap', my experience is that the pilots that don´t ask questions are the ones on whichs plane I wouldn´t put my family on.

Have you HONESTLY never asked a question that in hindsight was "dumb" ?

I certainly have. Still I ask if uncertain or not in the know. Maybe I´m just dumb... or not as perfect as others ?

Don´t get me wrong, if a dude comes on an writes: yeah don´t know why we switch on at 10° and therefore won´t switch it on, THEN I´m happy to join in on a virtual slaughter...

You have got the wrong end of the stick, but perhaps I shouldn't have mentioned exams.

From the earliest flying in SEPs, pilots learn (or should learn) that carburettor icing can occur in air temperatures above zero degrees.

Does the SEP phase of ATPL training no longer occur, or are they all fuel injected engines these days? Does it not worry you that someone who might be a qualified line pilot (and this is all conditional - we don't know if he actually is), does not know that icing can and does occur from +10 degrees TAT and below? If so, what did his ground school and line training consist of? I would like to be assured that Korean pilots do understand icing, because my brother will be flying with them later this year.

If the OP is an interested non pilot or wannabe asking a question, then fine, but he says 'we' which implied otherwise to me.

I am happy to be proved wrong.

Maybe I am too simple minded, but icing occurs at the wings of my flown aircraft mainly due to the abundance of water vapor. Temperature is secondary and only relevant for two things, how much water can be carried max in the atmosphere at a given temperature and what is the dew point temperature. Max vapor content of water in atmosphere goes exponential with temperature, so below a certain temperature there is no water in air anyways. Critical is the temperature area where there is enough amount of water vapor possible and physical effects can cause stickiness to the aircraft.

until ice crysals came about....

One thing of learning in a Cessna.,..not that hard to forget the carb heat and have the instrutor not remind you. those splutters and stops are something you never forget.

Ice crystals in the atmosphere won't stick easily at surfaces, worst is undercooled droplets ...

true but was answering in regards to his line 7 sentence,icing in the form of ice crystal is found at temperatures way below normal icing and do accumulate quite easily on engine surfaces such as compressors and can even block probes such as TAT ones.