Let's talk icing...

ridethisbike · December 9, 2015

We all knows it's bad. We all know the conditions it exists and to avoid it at all costs. But let's face it... there isn't much information (that I've found) that goes into too much more detail.

Considering the time of year, I thought it might be worthwhile to share experiences, anecdotes, or lessons learned from the mistakes of others.

With that, tell us about YOUR experiences with icing and icing conditions. A few questions to get the ball rolling...

What are your personal minimums regarding flying in near icing conditions?

Ever flown in snow? Has it ever been an issue?

My thoughts on this one are mixed, personally, mostly due to a lack of experience with snow in general. Being born and raised in AZ will do that to you... But my impression is that you don't really know how frozen the snow TRULY is, and as such, wouldn't want to fly in it (visibility reductions aside). Others have told me it's a non issue because snow "doesn't stick" to the blades. Not sure I believe them.

Any experiences with iced up blades?

How about ice being shed from the blades?

I'll let someone else link the video to the Art of Flight clip!

avbug · December 9, 2015

First of all, icing isn't bad. Icing in aircraft that aren't protected, or icing that exceeds the ability of the aircraft's anti-ice and de-ice equipment, can be bad.

Some of the worst Icing I've experienced was in Saudi Arabia, and some of the most consistent was back side of the Sierras during winter storms.

The worst icing conditions take place between 5-10 deg C, and -15 deg C. There are those who will say that liquid water and icing isn't possible in colder temperatures, but that's bunk.

I flew atmospheric research in Learjets, in aircraft equipped with underwing pylons with sensor packages, as well as cameras, pyrotechnics, etc, and one of our duties was to locate the greatest icing, generally with -10 deg C and at least 2 grams of water per cubic centimeter or greater. I've had ice buildup to 3" before, rapidly and have had to exit conditions because it couldn't be controlled; that is, by definition, severe icing. Any time it exceeds the aircraft capabilities.

This means that if you're in an aircraft not equipped or approved for known ice, any ice can qualify as severe ice. Something to think long and hard about.

It doesn't take much ice at all to cause a serious degradation of lift across an airfoil, be it a wing, propeller or rotor.

Icing is sometimes perceived as making a thickening along the leading edge, but I've seen it build tall fences and horns that protrude into the slipstream, from airfoils, including wings and propellers and spinners, and I've had it progress rapidly from initial appearance to the onset of control problems in very short periods.

I had an encounter with ice years ago in Arizona in a Shrike Commander, near the Mogollon rim, which resulted in a rapid loss of airspeed, an inability to maintain altitude, and a loss of speed down to blue line, then red line, and a descent below MEA and MVA, while IMC, and finally some airframe damage as ice began shedding from the blades and making holes in the side of the airframe. Elapsed time from appearance of ice until descent close to redline: 60 seconds, and that was from 180 knots down to 120 and then down to redline. Sixty seconds.

ridethisbike · December 11, 2015

Any experience to pass on about snow?

avbug · December 11, 2015

Quite a bit. Some may be relevant, some may not.

Don't assume, as many do, that one won't develop icing in snow, because one very easily can. Snow on the ground can also be blown into various parts of the aircraft and refreeze. It can lead to whiteout and disorientation, melt, runback and refreeze, and cause bigger problems that simply freezing along the leading edge. Now can cause induction icing, and pack off pitot and other pressure input sources for instrumentation or engine operation.

Avoid consumption, if yellow.

iChris · December 13, 2015

Considering the time of year, I thought it might be worthwhile to share experiences, anecdotes, or lessons learned from the mistakes of others.

The following prior post include information that maybe of interest with regard to this subject.

Flying with frosty blades...? Started by 280fxColorado , Nov 07 2012

Flying in freezing rain Started by touchdownjm , Apr 12 2013

The results of flight in freezing rain and icing conditions that accounted for 12 deaths are documented in the following four NTSB Reports.

The inadvertent encounter with inclement weather, including snow, freezing rain, and reduced visibility conditions, which led to the pilot’s spatial disorientation and loss of aircraft control.

The pilot’s inadvertent encounter with localized icing conditions and his subsequent in-flight loss of helicopter control.

the pilot's decision to continue VFR flight in deteriorating IFR conditions resulting in spatial disorientation and subsequent loss of control.

Related factors were: darkness, heavy snow, high winds, the pilot's perception of pressure that was induced by the conditions and events, and mountainous terrain.

"Inadvertent Encounters" or is it more accurately the pilot's deliberate decision to continue VFR flight in deteriorating weather conditions.

in·ad·vert·ent
ˌinədˈvərtnt/
adjective
adjective: inadvertent
1 not resulting from or achieved through deliberate planning."an inadvertent administrative error occurred that resulted in an overpayment"
2 synonyms:
3 unintentional, unintended, accidental, unpremeditated, unplanned, innocent, uncalculated, unconscious, unthinking, unwitting, involuntary;