What constitutes know icing?

[Lead Sled]

As I understand it we are not a known ice airplane, so despite all the equipment, I'm still grounded if there's an airmet covering half of the western us for ice 070-240?

That's correct. In the past, it wasn't an issue; but nowadays, it has become one. Chances are that you'll never have a problem, but if you ever were ramp checked you could end up having some explaining to do.

'Sled

 

[A Squared]

I's like to bump this back up and ask a question about a full-de-ice airplane. Our 340 has hot props and wing/tail boots with an alchohol windshield. As I understand it we are not a known ice airplane, so despite all the equipment, I'm still grounded if there's an airmet covering half of the western us for ice 070-240?

I have no desire to break the FARs, but I also have to explain to my boss why we can't go the Wy if there's an Ice Airmet valid.

You are correct, The aircraft needs to have been originally certificated for known icing operation, or be modified in accordance with an STC which allows flight into known icing conditions.
There are many Icing mods which do not allow flight into known icing, I used to fly a 310 with boots, hot props and alcohol windshield and a 320 with hot props, but neither were certificated for flight in known icing. THe best way of looking at it is that it gives you a little more time to exit icing in the event of an inadvertant encounter with unforcast icing conditions. I'm not trying to play coy with words here, I'm just trying to say that it's good to have the mods, but they don't allow you to fly into clouds when there's forcast Ice. I think you understand that, your problem is getting others to understand that.

 

[Sundevil]

I think we have all reached a concensus on the legal definition of known icing and I am not disputing the definition. The unfortunate part of having forecast icing included in the known icing category, however, is that for liability reasons the weather man is inclined to include icing in his forecast even when the chances are very remote. If a plane were to crash due to icing that wasn't forecast, I am sure that the lawyers would go after the weather dude immediately. The easy solution for the weather guy is to err on the conservative side and put it in the forecast. This leads to the forecast icing on a cristal clear day as was discussed earlier. It is too bad, but it happens all of the time. In icing country and icing season it is hard to get a lot of GA training done when abiding by the rules although there might be very little to no risk.
I was a meteorology major BTW and the same goes for forecasting tornadoes and any other severe weather. The theory is: better to warn a bunch of people and have nothing happen than not warn anyone and have a bunch of people get killed.
But one can cry wolf too many times and I think that has become the case with the icing situation.
Litigation is bringing down our society piece by piece.

 

[Dinger]

Coolyokeluke.....I saw your post about forecast icing and it being CAVU and still going.......somebody please correct me if I am wrong, but icing conditions in the airmet/sigmet forecast those conditions in 'clouds and precip'. If you are not in clouds or precip, you are not in the forecast icing conditions. I know I will probably get jumped on because there are obviously a few professionals on this site that have their sh!t straight. This is just how I would interpret it.....okay, let me have it guys.

(It's been a loooooong time since I flew a plane not certified to fly in icing conditions.......what was that law of learning.....misuse?)

 

[Lead Sled]

The AOPA Air Safety foundation just published a paper on this very topic. It's good reading and pretty much puts everything in black and white. www.aopa.org/asf/publications/sa22.pdf

'Sled