Known and Forecast Icing

Heartland · Post by **Heartland** » Sun Feb 18, 2007 4:07 pm

Hello All

A subject that has come up recently amongst myself and my colleagues is the differance between Known and Forecast icing. The relevance of this topic is important to us because the aircraft we fly is not certified for known icing.

Now I have looked at CAR's 605.30 and the way I read it is that Known and Forecast are the same with regards to a plane that isn't certified. So if I were to take off into an area where icing was forecast that would be illegal.

There seems to be some discussion about what the differance is though. Some people are saying that just because it is Forecast doesn't mean that it is Known. It would require a pirep from someone actually confirming that the icing exists.

Any input would be greatly appreciated

Heartland

gr8gazu · Post by **gr8gazu** » Sun Feb 18, 2007 4:40 pm

Don't know but if I was flying an aircraft not equipped, I would treat them the same. I don't care about the regs, just about living to fly another day..

C-GPFG · Post by **C-GPFG** » Sun Feb 18, 2007 5:34 pm

If it's not PIREP'd but forecast, would you fly into that area?

I agree with the above, treat forecast like known.

Percy · Post by **Percy** » Sun Feb 18, 2007 5:54 pm

The problem is fellas, that I have flown all day in forecast icing and have never seen a speck of ice. Flown within minutes, identical routes as aircraft calling heavy ice and have again not seen any. I have also flown when no ice was forecast and ended up with moderate to heavy. If you used icing forecasts as your go-no go decision you will never do much aviating during fall, winter or spring. IMHO ice forecasts are the least reliable weather forecast given to flight crew. Does you aircraft have any icing capability at all?

gr8gazu · Post by **gr8gazu** » Sun Feb 18, 2007 6:02 pm

The only "icing capability" mine has is in the galley. But I have plenty of bleed air anti-ice capability... Sounds like you are the expert in the area of non-equipped aircraft Percy so I'll let opinion stand as just that, an opinion...

Percy · Post by **Percy** » Sun Feb 18, 2007 6:06 pm

That's the problem gazu, I am certainly no expert, but i have experienced a variety of conditions that the forecasts do not reflect.

Empress Chief · Post by **Empress Chief** » Sun Feb 18, 2007 8:55 pm

The only difference between "known icing" and "forecast icing" is the forecaster being aware of it's existence. If it's forecast, then you're not going to fly into it. If it's NOT forecast, but a PIREP says it's there, (ie. known) you're STILL not going to fly into it.

The term "known or forecast icing" is just covering all the bases, and providing a worst case scenario. Icing is icing, whether it's expected or experienced, the dangers are the same.

JR

. . · Post by **. .** » Sun Feb 18, 2007 9:25 pm

that's like saying using an alternate with 0/0 is okay because no one has issued a pirep calling it that. give me a break. How do you think your insurance company is gonna read it when you bend metal?

Empress Chief · Post by **Empress Chief** » Sun Feb 18, 2007 11:28 pm

You're not following me here. If you have a situation (ie. MEL restriction) where you are not allowed to fly into "known or reported icing conditions", it's saying you can't fly into an area where there's a forecast of ice, even if there's no reports of it, OR into an area where there are reports of icing, even if there's not forecast for it.

The PIREP doesn't qualify, or disqualify the forecast, (as in your alternate example), it protects against situation where a forecast hasn't been issued, but icing conditions still exist.

Hope that helps.
JR

i aint gettin rich · Post by **i aint gettin rich** » Mon Feb 19, 2007 1:27 pm

my thought if its forcast then tech its known.. maybe there is none in but really if you are going on a flight and its says freezing rain, are you going to fly through it or try and avoid it.. most of the people i fly with wont go. why take the chance..stay above it or below it..