stalls and icing

One of the factors that can contribute to stalls is icing on the wings and tails of an aircraft. Simply, ice formation interferes with the normal aerodynamic flows over the wing and tail (aka horizontal stabilizer) leading to lower stall speeds and tragic outcomes. Yes, there are various de-icing systems that can be used in flight such as de-icing boots to rid the wings and tail of ice during flight. It is not my intention to get into the world of de-icing an in-flight aircraft.

In my travels on the internet learning about stalls recently, I happened on a link to aviation safety at a US Forest Service website and found a safety advisory from the Interagency Airtanker Board on icing. I found these safety reminders for airtanker pilots to be very poignant. As I read this advisory, what came home to me is that an airtanker pilot has the right to say “no” to flying into a situation where icing might be a problem and/or to get out of an icing condition before making a drop if called for.

Of course, I don’t know enough to know if airtankers even do retardant drops in northern States in America during cold weather where icing might be a problem. I am not an expert in meteorology, but I know enough to know that 33 degrees on the ground is going to translate to something colder at higher elevation. I also know that there is something called rime ice, which I think is caused by “freezing fog.” And rim ice can form on aircraft wings and tail.

Link to IAB safety advisory on icing (this is a pdf filerequiring a pdf viewer)

If that link does not work, go here and look under Interagency aviation safety alerts for advisory FS 09-01 on aircraft icing.

The advisory also provides a good description on ice formation as affects aviation that I found very helpful.