Icing Encounter


This last weekend I planned a flight from Galesburg Airport KGBG to DeKalb KDKB, which is just south east of Rockford, (for those of you who know the Chicago area.) I tryed my best to plan it so I wouldn’t be in those gusty 40 knot plus winds which consumed most of the mid-west this last weekend, but I was pretty limited due to avaliblility on rentals.

Anyway, me and another fraternity brother hopped in the C172 after the wx brief and set off for DeKalb. It was suppost to be pretty marginal VFR for the expected time of arrival, with conditions becoming IFR shortly after. Finally after a squabble with ATC due to my flight plan getting lost in the system I was cleared with via an abbriviated flight plan to KDKB.

About 15 minutes in we were above an overcast cloud deck and they started desending us for DKB. As we are thick in the soup ATC then tells us that contrary to no notams the NDB 27 app. was closed pending FAA approval. I somewhat expected this, as I called the dekalb fbo ahead of time to see if there were any important notices that didn’t make it in the notams, (as i’ve had several past incounters with important information being unpublished) I was told that the ndb may be out of service. I was also told it “could just be their ADF in the cessna trainer”, so it was pretty much hit or miss with the approach.

Being on steam guages and no IFR gps I decided to try a contact approach before residing to the alternate. The lowest ATC could clear me was 2400 and for awhile. I could see the ground and thought I would for sure have the airport made. Unfortuneately I was greeted with lower bases only 1 1/2 miles from the field. Thick in the soup I told ATC we’d try Rockford.

Here and there (with pitot heat on) I would glance at the struts and see if there was any ice build-up, but it remained almost perfectly clear. I was finally on with Rockford approach and was receiving vectors for the ILS 01 with circle for RWY25 when I looked at the leading wing edge through the foremost part of the windshield. I had about 1/4 to 1/2 an inch of mixed ice and it was quickly building. :open_mouth: I informed Rockford I had moderate mixed with it building, so they moved me to first in line for the approach. I did the apprach with no problem, but I’m not sure I would’ve had any second chances on it. After landing, and cleaning up my puddle in the seat I took a look and the prop, wheels, and entire wings which were completely covered.

I have most of my 400 hours in Piper Warriors and Archers (which are low wing) so I can see any accumulation clearly. I’ve always been told by multiple sources first signs of ice in a highwing will be on the wind struts, fuel drain, and any small protruding objects. **However, in this case there was no noticeable ice on the struts. **And if I would’ve saw a buildup that large sooner I probably would have diverted back to GBG where I could remain clear of IMC or have had Rockford keep me on top of the clouds instead of in them all the way from dekalb. **Also, I’ve heard under some conditions ice CAN sublimate off of the wing, but I am not sure when. **

All in all I can chalk it up as a good learning experience. It definately helped that my CFI home in Waukesha, WI is one who is not afraid of teaching in hard IMC and narly cross winds. I have even had the oppertunity of dealing with light unexpected icing with him on acouple other occasions so it definately helped me out in this situation. Thanks to good training everything worked out.


For the ice you describe, probably it would not subliminate in the time you break out to landing. My one only MINOR encounter with icing was on top of a stratiform deck where I was picking trace rime ice from the wisps of clouds I was going through and immediately asked for higher (and promptly approved) OAT for my encounter was 15F.

It took a good 10 to 15 minutes for the refrigerator looking frost to subliminate. I was amazed how quickly it built up in my short encounter with wispy stuff, can’t imagine what you had in solid IMC!!!

I know up your way, you live in a perpetual zulu airmet when clouds are around, but personally, if it was me, and MVFR was forecasted and the freezing level was anything near the visibile moisture (ceilings), I would leave the wheels on the ground. But that’s me of course!!! :smiley:

One question though, when you found that you couldn’t do a contact approach KDKB, did you go back into IMC turning back to Rockford? Did the ceiling drop behind you where you couldn’t maintain the VMC conditions that you were in previously?

Good post and most importantly, GOOD OUTCOME!!



If I recall correctly (and again that is a big IF) because it has been three days since I saw those perticular TAFs, but the conditions were calling VFR to marginal VFR for the rockford area through 00z. That was 8pm local for me and at the time it was about 5pm local. The front was moving west (of course) but Rockford was only catching the southern part of the system. Galesburg and other areas south were still VFR with top reports giving me plenty of space above the IMC at both Rockford and anything over Galesburg, promising for a safe ride back.

The ceilings weren’t lower than 700OVC when I got into Rockford, but they didn’t send me back up above the deck. If I would’ve noticed the ice sooner I definately would have requested higher until on the approach. It wasn’t until I was about 10 out from Rockford that I peaked at the leading edge through the tip of the windshield. It definately made me skeptical when I was in the clag for 15 minutes and I didn’t see a thing on the struts.

You are correct, we definately always see a zulu airmet this time of year. When dealing with the IMC in the winter months I always give me self outs. This entailed assurance of being able to get above the marginal VFR/IMC clouds around rockford and galesburg. Also, I always had the option to returning to Galesburg. I think this was a case where I didn’t recognize the situation as quickly as I should have.

Any idea why I didn’t see buildup on the struts/fuel drain?

Thank you for the post, I always enjoy hearing from other pilots. People don’t post often enough on this site.


Actually meant rockford and dekalb, not galesburg


Could be OR just maybe it built up that fast where maybe you hit a pocket of freezing drizzle or light rain in that cloud and also maybe it was not reaching the ground. Important thing about what you did, was when you realized the gravity of the situation, you took decisive action.

I haven’t flown a Cessna in 6 years, and never been in clouds in a Cessna (I fly a Sundowner), but on my Sundowner, I noticed especially on the ground on frosty mornings that anywhere there is fuel against the skin of the plane, I see heavier frost. Just curious for you, did the ice build up next to the fuel bladders (or heavier coating) around the tanks. It makes me think that where ever there is fuel, that gets / stays colder then a strut which may still have warmer air inside of it to keep that strut ice free. This is just a simple minded theory of mine anyway.

Actually, on the contrary, dig through the past postings, and you will see plenty of war stories, hangar lying (er I meant flying) splattered throughout these forums.

I know I got plenty of mine throughout, from flight planning up in the NE quadrant of the country (which I got some valuable advice on how to file IFR!) to my inflight cylinder failure.

And it appears to me we got cub drivers to jet jockey pilot experiences to tap into for questions.



Most of the accumulation was on the leading edge. It was almost like frozen, compacted snow. However, I did get a substancial buildup in the area where the wing contacts the windshield. My guess on this is the air rushing through the exterior vents kept this part chilled so it collected faster.

As far as collection around the fuel bladder, I’m not really sure. It makes sense though, as this definately was the case with air vents.



Just wanted to reply because I have almost killed myself by screwing around in the soup with a Piper Cherokee.

About 10 years ago I had been flying on top of a layer at around 10,000 feet until it finally caught up to me. I picked up a trace of mixed ice as I descended through 8,000 feet and was fine after that. I continued in the clouds at 4000 feet for about 30 minutes before deciding to land and get fuel/check weather again. The trace of ice sublimated at 4,000 and ice was never encountered again throughout the approach.

Being really stupid, I decided to takeoff again in the crappy weather because I thought that I REALLY needed to get home and there was no ice below 6,000 feet. If I remember right the clouds were at 1000-1500 feet when I took off. About 5 to 10 minutes after entering the clouds, crap loads of mixed ice started to form on the wings. The only “out” that I had left myself was to do an ILS back into the departure airport. The only problem was that vector to the ILS took a long time.

I will never forget looking out at the wings and seeing a huge chunk of ice that was rapidly working its way back on the top of the Hershey bar wing. The temperature probe on the window had a HUGE U-shaped chunk of mixed ice on it. I was flying at almost full power and all I could think about was how it was going to feel when I descended into the ground and my face smashing into the instrument panel (I was really wishing I had shoulder harnesses).

When I finally got onto the ILS, it was taking a XXXX hair under full power to maintain the glide slope. By this time I checked the weather again and the airport was down to minimums with heavy snow. I knew that there was no possible way of going missed approach, so I was going down to wherever the ILS took me. Did I mention the shaking of the iced up prop, yea that sucked too.

Well it ended up being the best approach that I had ever done. Im not sure what altitude the runway came in sight at, but it was low. When I pulled up to the FBO the ramper came out and said Holy XXXX how the hell did that thing fly. There was, I kid you not, ice half way back on the upper side of the wing. It was just above freezing on the ground so we were able to break the ice off the wings and there was just a big pile of it around my wings (I wish we would have had camera phones back then). I ended up spending 2 nights there until the weather cleared up and have never flown a non-certified aircraft into icing again.

Anyway, I made a lot of stupid choices that day, but I also learned a good lesson. Do not fly into known ice if the plane is not approved. Even if you think that there is a good out, ATC might need you to maintain an altitude in the layer for traffic etc…

My thought is if it is near freezing and you can’t go VFR because the clouds are too low, there is no reason to go IFR and attempt to climb through a layer to get on top even if you have a pilot report. Thats just old information. Also, don’t rely on icing reports from jets, the heated windows and wings make them unreliable. If you can go VFR why even enter the clouds?

One other thing to think about: “known icing” is any visible moisture with temperatures near or below freezing. genebenson.com/docs/icing_exp.pdf If your flying in a cloud near or below freezing, your breaking the regs.

Sorry for doing a little preaching, I’m glad that everything worked out well for you guys and that you also learned something from it. I also just wanted to share this to get people thinking a little more to prevent someone from doing stupid crap like I used to.


Thanks for posting, very interesting. So essentially, based on that document, no flying in snow flurries? May be extreme, but it’s visible moisture. Or is snow considered “moisture”???

I have been chatting with a pilot in MN, and he flies in snow below the cloud deck and I have been questioning that if it’s legal or wise, since snow is visible moisture.

I have had no snow flying experiences living down here in Mississippi, and I have been told, the higher you climb, the warmer the temperatures, which would lead me to think better chance of icing the higher you go.

While it is very rare we get icing conditions at the altitudes I fly at, it does happen, but when it’s that cold, heck, it’s too cold to preflight anyway :smiley:



That’s an interesting letter from the FAA regional office. That is contradictory to what I’ve always used as the definition, and also what the AIM has to say about it.
Taken from this thread:


And if the three of us called our local FSDO, we would get three different answers even different then what AIMS sez. :open_mouth:

Personally, it really comes down to common sense, just like dealing with thunderstorms…

But if you read that letter from the FAA regional office in this post to the letter of the law, unless if snow flurries is not defined as visible moisture (being solid in nature), then you are not suppose to fly.

Common sense though sez differently in my eyes, that sure, it’s safe to fly in snow flurries, but never had to make that decision.

I personally would go fly in snow flurries but not enter IMC conditions.



As CFJames pointed out this is not true

I could not get the link to the FAA letter to load, but I regularly attend AOPA conventions and this issue was presented recently at a “Regulations” seminar.

A person sent a letter to the FAA inquirijng what is “known icing”? The FAA responded with an outragously conservative response. They “concluded” known icing was any time the temperature was 32F or below with a small temperature/dew point spread.

Obviously, this would restrict almost all of the northern midwest GA population to flying only about 3 months of the year. The FAA retracted the statement the following day and concluded the statement issued was done so without autherization. Thus, the definition of known icing IS legally based on PIREPS.

Not all clouds below zero contain ice. I’ve worked with numerous CFIs in the midwest during these months we will occasionally fly in IMC in clouds not NOT accumulate ice, thus ice is a very subjective thing, and it can not be concluded as “visible moisture.” In accordance with the regulations if a pirep pops into the system we definately keep the wheels on the ground. :smiley:

I also feel I have understressed the numerous “outs” I give myself when flying winter IMC. I ALWAYS ensure I could climb over a cloud deck IF I did start picking up ice. Also, I know I can make it to a VFR alternate while staying out of the clouds enroute. Thus, I can remain clear of the ice if I started picking some up. Again, regardless of all these “outs” I would never launch if PIREPS said otherwise.

Again, I learned how to recognize ice better in a C172, or high-wing in general.

In repeating my flight with the information I had avalible **at the time **I would still have launched. (Taking into considerations the “outs” I had. – VFR alternate, and I could cruise above the cloud deck)

The problem arouse because I failed to recognize the original onset of ice. If I would have seen it sooner it would have only resulted in trace to light. Specifically, I would have noticed the trace ice creeping along the leading edge, informed Rockford, and climbed above the ceiling. From there I would have had two options: either shoot an approach into Rockford, or stayed above the clouds and returned to Galesburg where it was VFR.

In this senario I wouldn’t have sat in IMC and let it accumulate to moderate or severe. It’s all risk management, and with these considerations I can remain safe and legal.


The debate about what constitutes known icing has been going on for as long as there have been FAA/CAA regulated airplanes and cold clouds to fly them in. At one extreme are the people who say that a Pirep is the only known icing (because someone was actually there to observe it) and at the other extreme it is any situation where there is a forecast of icing or there could potentially be icing. We won’t resolve that question on this board, but for what it’s worth, here is a practical definition: known icing is problematic in any situation where an aircraft accident or incident occurs as a result of non-FIKI aircraft icing, or an FAA inspector observes a non-FIKI aircraft land covered in ice. While there are obviously other icing situations, those are the ones with consequences, either regulatory, economic or injurious.


EDITED to remove total mess of quotations in origional response for clarity sake.




while you certainly could use this criteria and it would be prudent risk management, you would effectively be grounded for more than half of the year up north. Most pilots that I have met in the north (including the very icy pacific northwest), have a broader approach that centers on having an out. That way, when you encounter ice (which you will during the fall, winter and spring), it will not have bad consequences.


Agree to a point. That out must be there, no question about that, but certainly, there are many days where the ceilings are VFR conditions and there is no need to climb in IMC, that probably (no stats to support this, just observations when I was a non pilot in Ohio) would account for 1/2 of the cloudy days. On the other 1/4 days, clouds may have been thin enough to see sun, and of course I would see no reason to fly through them even though one does risk picking up light icing.

The days I am talking about are those remaining 1/4 days of the equation, with low ceiling, crummy look days that any plane not certified for icing should be in days. 700 foot OVC, gonna snowstorm type of look would be this kind of day.

Again, if you can see the sun through a 700 foot OVC, I see no reason for not launching as long as you know it’s the same on the other end of your flight.

What bothers me about babolatt16 posting is that he would (my perception) launch under the same circumstance and forecast, and that is what really bothers me.

We all make questionable decisions even when one does their best to think it through.

For me, when I departed Ohio on a cold dreary November day, ground temp was 36 degrees and I was getting light sleet and snow on the ground. Ceilings were 300 OVC.

While I took off with the misconception that I would hit warmer air because after all, in order for sleet or snow to form, it has to go through a freezing level, I failed to consider that I am potentially exposing myself to a layer of below freezing conditions inspite the forecasted freezing level of being 8000 and I filed 6000. The sleet was not forecasted, **clue number one! **

Learned a valuable lesson from “hanger flying”, that was for sure as others said they would have never left the ground!

As it turned out, the forecast was right, I climbed, watching the OAT and it was above freezing the entire climb and broke out above the deck. I got lucky… The precip was being generated from an upper deck cloud.

picasaweb.google.com/allenlieber … 4741627650

picasaweb.google.com/allenlieber … 6151693042

Expanding on my minor icing encounter posted earlier in this thread.

Later on this above mentioned flight, when the tops became higher, and I was on the back side of the cold front, temps were dropping, and I was thinking cooool, get some magical IMC time. It was only when I had to add a touch of power while on cruise that the bells went off, something not right, looked at the OAT, and 15 it was (my minor icing encounter described earlier in this thread). Looked on my wing where it was white, no observable ice, but when I looked at the blue stripe, I could see that rime ice had built. In my case, my out was up, but clearly as you can see in my picture, it was a no brainer decision, go where VMC was. That little bit of rime was enough to cause a change in my flight configuration. I have a white tail feather, and couldn’t tell how much ice was back there.

Now, my question was just how was I going to let down. I kept monitoring the ASOS in KBWG and they said BKN 4500, so my “out” was to ask ATC to slam dunk me if I didn’t see ground in my initial phase of the approach knowing I would be IMC for about 2 minutes (I would have made a rapid descent). As it turned out, clouds were broken and I could see the thickness and as I descended the temps went well above freezing quite quickly as the ground temp at KBWG was 42.

Truth be known, even after all my flight planning, I didn’t plan for ice, nor did I expect to be behind the front going further south down to KBWG.

So, yes, really things happen, but what I am hoping to bring home, is no matter what AIMS, FARS or any regulatory regs say, common sense must prevail for icing conditions. If you see clouds, can see the sun through it, I would suspect most C172s or my Sundowner can penetrate those clouds, pick up light ice and let sublimination take it’s course.

But when I hear pilots taking off on those low 700 OVC days and go on a forecast of breaking out on top a couple of thousand feet up, amounts to a lot of time and exposure to a potentially dangerous situation, I cringe and question their judgement.

And the situation does not get better as you climb in IMC, as you probably know, the drops are larger at the tops of the clouds which would excasperate the icing just that much faster.



Yea, that is a pretty good definition.

All it takes is landing with a little ice on the wings and the FAA roaming around the airport to get a violation. It looks like you guys were just up building some time, probably in hopes of getting a professional flying job soon. Don’t risk a violation that you have to explain during your interview.

You won’t be flying for only three months out of the year. There are tons of good VFR days during the winter in the Midwest. Actual time can be built in the summer. Why risk the violation or your life.

Sure, as Allen said there are many times when it can be done safely.

As far as the outs you had, Flying in to an airport that is marginal VFR with a forecast to go IFR is not a good one. Climbing to the top of a layer is also a bad one. I really didn’t take long in the ice before my Cherokee took almost full power to maintain altitude, climbing was out of the question. And I didn’t need a pilot report because I had flown in the same area without icing 30 minutes prior. Remember that your prop is also not de-iced and its effectiveness can deteriorate fast. Really the only good out is being able to descend below a layer to VFR weather.

Again, I just wanted to share my story to get pilots to think about what can happen quickly to an airplane in icing and how quickly icing conditions do change. Im really not trying to criticize you or put you down babolatt16, just to let you know what to look out for. Best of luck to you and have fun.


I’m curious to know if anyone has actually seen or heard of this actually happening without an associated accident or incident. Clearly an inspector could take action, but I’ve not heard of it happening.


We obviously have very rigorous and sincere opinioned details, (which in the grand scheme make a big difference) regarding the risk management of winter IMC.

Allen, I never remarked having decreased performance. Were you alluding to Falcon1’s experience?

I have always been told I have a tendency to exaggerate, so perhaps I mis-conveyed the severity regarding the amount of ice. I was still maintaining normal cruise speed at 75% power cruise setting; not screaming for priority over the radio or racking in the power praying to stay airborne.

I promise this will be the last quote I contend in the post! :wink: We do not have the original TAFs, METARS, prog charts or any other necessary weather information to make even “go” or “no go” assessments regarding all aspects of the particular flight I took. Thus, it seems trivial and rhetorical to squabble over whether it was “safe” in the reference to IMC icing – which is a significant consideration in itself; again, a consideration we are making with inconclusive weather information which may also be biased.

I agree 110% CAFlier… I have flown with many different CFIs at a variety of different flight schools since I began flying about 4 or 5 years ago. If this type of risk management was not used a majority of our flights would be scrubbed. Although, I feel I am perpetuating the misconception that I’d launch (or have launched) into very low ceilings with unrealistic “management of risk.” There are definitely MANY times when we keep the wheels on the ground without the ultimatum of PIREPS.

Allen, I apologize if you feel I have at all maliciously challenged your knowledge or experience. You sound like a very experienced pilot who has been around and probably have more ratings than myself.

At school last year I began taking lessons at a new flight school, as I go away for college. This school is primarily a charter hub, and on demand charter accounts for more than a majority of their business. I am a person who will spend 30 minutes or more on a pre-flight, (especially if I am flying a long x-country), look at weather on ADDS days before a planned trip, and again before calling wxbrief. When I saw what a “get in and go” mentality the entire operation had my first reaction was “they can’t be safe pilots.” However, I just realized they had a different method for doing things. It doesn’t always mean their approach is dangerous, just different because they must accommodate different variables.

I would hypothesize this is a similar case regarding our discussion. Anyway, this post got way too long. I appreciate all of the input fellas. Ive had fun mellin this around in my brain.


CRAP, quoted the wrong name all the way throughout! SORRY!!!

Was directed to Falcon1.

Again, my quote above should have been to Falcon1. You didin’t encounter moderate to severe icing like Falcon1 did!!!

Again, you did nothing different then I did, my quotation should have been at falcon1.

I am only instrument rated, nothing more. Again, my response was totally directed at falcon1, as you probably can tell, I copied his text, but attributed to you, totally my mistake and I apologies!!! And I didn’t feel any offense by anybody’s comments, and welcome any challenges, as it’s those challenges that make me that much better a pilot.

Again, my apologies for attributing the wrong text to you. My original response to you still stands :smiley:

Clearly Falcon1 was the one I meant to respond to as he was the one sliding down the glideslope full power.

I will edit and attribute the proper person.




All of the stuff that you re-quoted was NOT said by me. I think that when you were typing a response you were just confusing the stories a little.

No need to change it all again, just letting you know.