Icing in cloud.

[Pilut]

Well it's that time of year again (at least at CYAM).
The freezing level is at the surface or below, and according to our SOP's we can't fly in cloud anymore. This is based on the assumpsion that if you enter cloud above the freezing level you'll pick up ice. Well in my experience, not every cloud that's below freezing contains ice, in fact it's pretty rare and I've only ever seen it between about -5 and -15. Anyone else have any thoughts on this? Maybe my experience is too limited or I'm just really lucky.

Cheers,

[Freak On A Leash]

Technically, when you have visible moisture and the surrounding temperature is below freezing (or the collecting surface) you have a chance of picking up ice. This does not necessarily mean that you will get ice since a certain moisture content is needed (you can relate this to relative humidity). And some clouds are purely ice crystals (e.g. cirrus), where the temp is always below zero, but you won`t pick up any ice there.

The best thing to do is to play it safe. If the temperature is around freezing and there is visible moisture, then you should stay away (provided you don`t have any de-icing equipment onboard). If it`s really cold, well, then it`s a different story, but again, the best thing to do is to play it safe - the good thing about weather is that it always changes:)

[justcurious]

I'd say it was more luck and inexperience you had going for you in past winters. Once you leave the College level, and move onto something with enough equipment to fly into known ice, you'll be startled by the variety and quantity of ice you can pick up. Inthe Arctic in the winter you can go for months without picking up any, and then run into enough in the Pittsburgh area to not be able to maintain level flight.

Importantly, (hence the SOP) your aircraft was not tested in the certification process for flight into known ice, so at the point you fly into icing, you become an experimental test pilot.

The MNR people around the corner have Twin Otters, so ask to see their Nasa Tail Ice Video. It's pretty revealing- you won't recognize the symptoms until you are about to have an exceptionally bad day!

While everybody wants to fly, especially at your present level, an important part of this business is learning when to say no.

[wde]

Excellent responses. Ask the more experienced pilots over a wobbly-pop some night about their experiences in known ice..I am certain that you can learn a thing of two.

In my view, if you have an SOP keeping you out of the cloud below 0 degrees, then good on them. You can always tell the passengers that the safety policies of your company preclude you from flying right now.

I work in EMS, and the live by the mantra that 4 > 1 in all circumstances. (Don't risk your life, that of the crew to maybe save 1 life.)

There will always be tomorrow.

[bearcat88]

Very nice bit of discussion here. Our group just finished annual winter ops briefings and the subject of ice accretion and its unpredictable and sinister ways was at the forefront. With emphasis on the "unpredictable" I think that the advice to follow your SOPs regardless of whether or not you think that there is ice is always a safe bet - especially with pax in the equation. Our airplanes do not have anti-ice on the tail so we rely on speed to burn it off but even that doesn't always work. That NASA ice video is right on the mark.
Keep warm ... spring is only six months away.
88 :rolleyes:

[penguin]

If you have boots, climb to 7000' eastbound and 8000' westbound and you will be on top most of the time. Unless you are going into major airports, you wouldn't be in the clouds for too long anyway. Of course, most important of all, stay clear of the cloud.