Carb ice? (and beating myself up...)

[Lndwarrior]

I've been flying recreationally for over 30 years. Mind you 20 of those was pretty much the same 1 hour flight.

I'm on multiple aviation forums every single day, multiple times, for years now. I read all the accident reports. I use checklists (mostly). I am extremely safety conscious.

And today I was (mostly) an idiot - and my precious wife was in the plane.

Plane is my homebuilt Zenith CH601 XLB with an Lyco O-235-C1 engine, MA-3A carb, dual electric fuel pumps. I've put almost 600 hours on on her.

Today, wifey and I decide to take a scenic flight over the foothills of the Sierras where we live. We take off from Pine Mountain Lake (E45), marvel at the snow-capped Sierra's in the near distance, and cruise over Don Pedro Reservoir around 5000 feet agl.. Plane is running great in the cool, smooth air. The foothills are green and beautiful. I practice some slow flight as we head toward Calaveras County Airport and decide to do a landing. Prior to landing I pull the carb heat, as always, and make a decent landing.

We take off again, heading back to E45, with the power set at 2450 cruise rpm. We're up about 4000 agl just past Columbia Airport when I get the feeling the engine is running just a little rough. Am I imagining this? I pay more attention and it does seem like its running not quite right. So push the throttle in watching the tach to get it up to 2600 rpm or so. There's a slight stumble, but zero rpm increase.

I pull the throttle back and then forward again and the same thing happens. The engine does sound a little rough (though my wife did not notice it) but there is definitely something wrong with the engine. I pull the power back to 2400 and it seems reasonably smooth.

Yeah, with the clouds forming below us, temps in the low 40s, every damn rookie pilot in the world is thinking, "Pull the carb heat, idiot!".

Guess what I didn't do???

Well, I wasn't a complete idiot because all I thought about at that point was that we were within gliding distance of Columbia Airport. I rolled the plane into a 180, forgot to change to the airport frequency (Bro! You're on Guard!). F**k, mistake number 2. Change to the airport frequency and announce my position. The engine is running smoothly at this point and I dont touch anything until we're high abeam the numbers and know I have the runway made.

I landed long (telling wifey, I am NOT coming up short!) and pulled off the runway. Did a full power runup, no issues. Check both mags, no issues. Checked EGT and CHT (in the air beforehand as well), no issues. Check the fuel pressure, no issues. We sat there for a while, did a long taxi, another full power runup and no issues. AND I STILL DIDN'T THINK OF CARB ICE!!! Don't ever fly with me, I'm an idiot...

E45 is about 20 miles from Columbia so I make the decision to climb up to 7500 msl above Columbia Airport before heading back to E45. I want as much altitude in case something goes wrong.

I decide that a straight in to runway 09 at E45 is going to be the shortest route to getting on the ground. I stay up way high until 3 miles out then I pull carb heat before reducing the throttle - and the friggen light finally goes off in my brain - carb ice.

I'm still beating myself up wondering how the hell this didn't cross my mind beforehand. It's no excuse, but in 30 years of flying I've never experienced carb ice.

Yet, I still can't understand why that wasn't the FIRST thought on my mind? I am getting older and maybe this is a sign that it's time for me to reconsider continuing with this passion of mine. I just see no way of letting myself off the hook for this.

If I had been flying by myself, I may not be so concerned about my actions, However, my precious wife was in the plane and she deserves a better pilot than this. What if we hadn't been in gliding distance of an airport and it had got worse and I still didn't recognize it?

I have some serious thinking to do.

( I will be checking my fuel system just in case. There is a slight chance a temporary blockage of some kind could have caused this.)

 

[jesse]

I've missed the fact that carb-ice was occurring myself once too. Even worse, I was the instructor in the plane that was supposed to be preventing those sort of mistakes. Luckily the student was @DavidWhite. He noticed the RPM reduction before I did and knew his airplane better than I did. Told me that he thought we were getting carb ice. I told him I thought he was being paranoid but throw the heat at it and lets see. He was right. I was wrong. **** happens. Learn from it and move on.

I am getting older and maybe this is a sign that it's time for me to reconsider continuing with this passion of mine. I just see no way of letting myself off the hook for this.

It's very hard to self-evaluate whether age has caught up to you. Fly some with an instructor you trust and ask them. If they tell you to hang up the wings, then maybe do that, but otherwise...keep flying...

 

[FPK1]

Did you use carb heat landing at Columbia Airport? You probably did out of habit...

Thanks for the confession, rest assured it will help someone.

 

[Jim K]

Thanks for writing this; it's always good to have a reminder. My plane is fuel injected, but I occasionally fly a 172 and I'm paranoid about carb ice because I have virtually no experience with it. In 400ish hours in carbureted planes I THINK I had carb ice once. It's rare enough to forget about it unless you have a real icemaker

I too am curious if you remembered to pull the heat on at Columbia. Sometimes when you're rattled things get forgotten, as your radio snafu illustrated. Or maybe you did it out of habit (or checklist usage.....) and it solved the problem before you realized it existed.

Don't beat yourself up too bad. We all make mistakes. If we can fly out of them and learn from them then we've successfully moved a penny from the luck bucket to the experience bucket. I bet you won't forget carb heat again. I recently flew myself and my wife into a pretty nasty weather situation. We made it out thanks to a great controller, my hard-earned instrument proficiency, a well behaved airplane that I'm very comfortable in, and yes, a withdrawal from the luck bucket. Made a big deposit into the experience bucket and I can promise I won't do that again.

 

[Gary Ward]

In 1400 hrs flying my 172N I experienced it a lot.
Early on I thought something else was wrong?
Recently I overhauled my air box because it was worn out and this is ice season.
Glad you figured it out and made it home safely.

 

[GeorgeC]

Carb heat early, carb heat often. Bored in cruise? Turn it on for a few minutes. Doesn't cost anything, helps pass the time.

 

[Matthew]

I’ll take, “Things you’ll never forget again for $200, Alex!”

I’ve had carb ice once. Fortunately I considered it and got it handled. I was about to start a descent to land and, hopefully would have remembered the carb heat anyway during the checklists. All it takes is that one real experience to burn it into memory.

 

[SixPapaCharlie]

I have never had it and I always think when it happens, I am not going to think to pull that knob.

 

[Gary Ward]

Descending through clouds will do it every time. Now my wife knows what it is and doesn't freak out as much as she used to.
I had it climbing out of my airport a few week ago 2 days in a row when the dew point and temp were close and it was 29°F in the air. I usually climb out about 3/4 of the way and then give it a little carb heat to keep it at bay.
And yes during cruise I can feel it build up in the form of slight vibration and it goes away with some heat. I used to think my propeller was loose or something was coming loose.
It only took me about 1000 hrs to figure all this out. Duh.

 

[Jim K]

Descending through clouds will do it every time. Now my wife knows what it is and doesn't freak out as much as she used to.
I had it climbing out of my airport a few week ago 2 days in a row when the dew point and temp were close and it was 29°F in the air. I usually climb out about 3/4 of the way and then give it a little carb heat to keep it at bay.
And yes during cruise I can feel it build up in the form of slight vibration and it goes away with some heat. I used to think my propeller was loose or something was coming loose.
It only took me about 1000 hrs to figure all this out.

This is in a 172N? Is that an O-320? I fly an M, but only have about 35s hour in it. I thought the Lycoming Cessnas didn't have as much issue with carb ice.

 

[Gary Ward]

This is in a 172N? Is that an O-320? I fly an M, but only have about 35s hour in it. I thought the Lycoming Cessnas didn't have as much issue with carb ice.

Yes 172N with a 0-320 H2AD engine.
I learned to fly in 172S with fuel injection so carb heat was not talked about nor was it on the checklist.

Then my buddy CFII says his old cheerokee does not make ice, so he never wanted me to use it on his plane while I was flying it. He was a bad influence on me early on and made me think it was not a problem for the most part. Until one day him and I were flying an ILS into CVG and when we went missed it happened in my 172. We thought we might have to land as we did have 11K' of runway underneath us. I pulled the heat and it cleared up. We both kind of freaked out. This was a few years ago.

I found the flapper valve in my old air box worn out, there was at least a 1/8" gap on both sides letting hot air leak through all the time keeping ice at bay. Now that it seals up much better I find carb ice happening more this time of year. Engine runs better with cold air now.
I use it all the time now even when I am at the the bottom of the green band, can't hurt especially during the winter.

First I was thinking Mag, then I was thinking carb but ultimately it has been carb ice from the beginning.

 

[Jim K]

I found the flapper valve in my old air box worn out

That's likely the reason I don't see it as much in the one I fly.

Then my buddy CFII says his old cheerokee does not make ice, so he never wanted me to use it on his plane while I was flying it. He was a bad influence on me early on and made me think it was not a problem for the most part. Until one day him and I were flying an ILS into CVG and when we went missed it happened. We thought we might have land as we did have 11K of runway underneath us. I pulled the heat and it cleared up. We both kind of freaked out.

I learned in a PA-28. Everyone I talked to in the club, as well as CFIs from the local flight school that flies Archers, told me carb ice is really not an issue. So my primacy is to not worry about it, backed up by 400 hours behind an injected engine. Hence my paranoia in the Cessna.

 

[Dan Thomas]

This is in a 172N? Is that an O-320? I fly an M, but only have about 35s hour in it. I thought the Lycoming Cessnas didn't have as much issue with carb ice.

As much issue, as I highlighted. But ANY carburetor can generate ice, given the right conditions, and Lycomings can and will still ice up and kill you dead.

The Cherokee's carb is surrounded by exhaust pipes and the muffler. It gets not only heat from the engine sump, but radiant heat off all that exhaust plumbing. But get into a long , low-power glide when the temp and dewpoint are close, and you WILL get ice, and maybe the engine will be dead by the time you go to open the throttle again. A dead engine generates no exhaust heat for the carb heat, so now you really are dead.

The problem with carb ice is that we can't simulate it, so students often never experience it while training. They get that ticket, thinking that carb ice is a bunch of old wives' tales, or that it's just a wintertime thing, and eventually it bites them hard. If you learn in the summertime in the great central deserts and plains, you will seldom see it, but then you take a trip to one of the coasts--especially where it's really green, lots of moisture--and you're getting it constantly.

 

[Racerx]

Having never experienced carb ice in reality I can only imagine it would be similar to co. You don't know you have it. It's one reason I bought the Delta Zulu's. Perhaps it might be a good idea to invest in a carburetor temp probe? Not that you'll ever have the issue again...or if throwing carb heat wouldn't be your first reaction to any stumble. Real or imagined.

I was actually thinking maybe he didn't turn carb heat off. And we're running overly rich.

 

[Racerx]

That's likely the reason I don't see it as much in the one I fly.

I learned in a PA-28. Everyone I talked to in the club, as well as CFIs from the local flight school that flies Archers, told me carb ice is really not an issue. So my primacy is to not worry about it, backed up by 400 hours behind an injected engine. Hence my paranoia in the Cessna.

In my 180 poh it says only apply carb heat when suspected. Not sure clarity came about in later models or not.

 

[Lndwarrior]

Did you use carb heat landing at Columbia Airport? You probably did out of habit...

Thanks for the confession, rest assured it will help someone.

I don't think I did use the carb heat at Columbia. I think I had the idea that, "the plane is running ok now, don't touch anything!".

Also I was hyper-focused on the possibility of having to glide it in, which I could have done.

In retrospect, I should have pulled carb heat...

 

[RyanB]

Happens to all of us at some point or another. It definitely doesn’t hurt to get in the habit of pulling carb heat on a regular basis. When I started flying the Cherokee’s/Archer, I was taught that carb heat was used if you suspect you already have carb ice, whereas carb heat in the Cessna’s should be used for the prevention of carb ice (yes, I understand the differences). That said, it’s not a bad practice to treat both the same and even cycle carb heat periodically during flight and during descent.

When you look deeper at it and see it in action, the engine can be running at several hundred degrees, but the carburetor will just be sweating. The right atmospheric conditions and you’ll get ice.

 

[Dan Thomas]

Happens to all of us at some point or another. It definitely doesn’t hurt to get in the habit of pulling carb heat on a regular basis.

We don't have to be surprised by it. We have resources that should have been used in the training we received, but some instructors tend to ignore the stuff they themselves don't understand, and carb ice is a commonly-ignored subject.

FAR 91.103:

Each pilot in command shall, before beginning a flight, become familiar with all available information concerning that flight. This information must include--
(a) For a flight under IFR or a flight not in the vicinity of an airport, weather reports and forecasts, fuel requirements, alternatives available if the planned flight cannot be completed, and any known traffic delays of which the pilot in command has been advised by ATC;

Familiar with all available information for that flight. Well, we have METARS readily available just about anywhere on your cellphone, at least. And they have little numbers that tell us much about the risk of carb ice.

In Calgary right now:


See that 09/M04? 9 degrees C, dewpoint minus 4. A 13-degree spread that will present a lower risk of ice, though it's still possible. Lets go a few hundred miles east, to Saskatoon:



Different story there. A two-degree spread. One needs to expect carb ice even in a Lycoming. It's almost a certainty.

Then we have any number of carb ice charts:



Plot those temps and dewpoints from the METARS and see the risk levels.

 

[Gary Ward]

My wife and I were descending down around clouds with carb heat on, leveled out over Lake Erie on our way to PutnBay. I gave it some power and then closed carb heat after about 10-15 seconds of cruise power it got ice and stumbled . That time it took about 4-5 seconds to come back. Inside I was a little concerned until it came back. Calmly my wife looks over at me and says “why don’t you just leave it on?”
I thought she’s right. Screw it especially over water. This was last fall.
This was when my air box was leaking cold air into the hot air making for slower reacting , lower temperatures when you need hot air.

 

[Lndwarrior]

We don't have to be surprised by it. We have resources that should have been used in the training we received, but some instructors tend to ignore the stuff they themselves don't understand, and carb ice is a commonly-ignored subject.

FAR 91.103:

Each pilot in command shall, before beginning a flight, become familiar with all available information concerning that flight. This information must include--
(a) For a flight under IFR or a flight not in the vicinity of an airport, weather reports and forecasts, fuel requirements, alternatives available if the planned flight cannot be completed, and any known traffic delays of which the pilot in command has been advised by ATC;

Familiar with all available information for that flight. Well, we have METARS readily available just about anywhere on your cellphone, at least. And they have little numbers that tell us much about the risk of carb ice.

In Calgary right now:
View attachment 124787

See that 09/M04? 9 degrees C, dewpoint minus 4. A 13-degree spread that will present a lower risk of ice, though it's still possible. Lets go a few hundred miles east, to Saskatoon:

View attachment 124788

Different story there. A two-degree spread. One needs to expect carb ice even in a Lycoming. It's almost a certainty.

Then we have any number of carb ice charts:

View attachment 124789

Plot those temps and dewpoints from the METARS and see the risk levels.

Conditions during my flight were in the moderate cruise power/ severe icing any power.

Carb icing started in cruise power setting.

The clouds that started forming below my altitude should have clued me in to the potential for this. It certainly will in the future.

 

[Half Fast]

The Cherokee's carb is surrounded by exhaust pipes and the muffler. It gets not only heat from the engine sump, but radiant heat off all that exhaust plumbing.

Yes, any carb engine can develop ice. The amount of susceptibility depends upon the particular airplane installation, especially where and how the carb is mounted. So far I've had no problems with my Musketeer but I'm sure it can happen. The carb is mounted on the aft side of the engine, not the sump, and it's not near the exhaust.

I'm a bit curious whether anyone has experience with ice while using a carb'd Rotax. The Tecnam LSAs I trained in all had Rotax engines, and there was no carb heat. I asked my instructor about it, and he just said those engines couldn't develop carb ice, but he gave no reason and I'm skeptical.

 

[jcurry]

You're human. Don't beat yourself up.

 

[asicer]

I am getting older and maybe this is a sign that it's time for me to reconsider continuing with this passion of mine. I just see no way of letting myself off the hook for this.

...

I have some serious thinking to do.

First, figure out a way to forgive yourself. Based on what I know from your previous posts to this forum, you seem to owe yourself at least that much.

I may have a ways to go before I have to face the decision, but I would hope that when I get there that I approach it with a clear head.

 

[Half Fast]

I am getting older and maybe this is a sign that it's time for me to reconsider continuing with this passion of mine.

Maybe it's just time to consider a fuel-injected engine.....

 

[Zeldman]

I have some serious thinking to do.

Just wait until you accidentally leave a seatbelt that is not in use hanging out the door...

I did that once as a student pilot on a solo flight. Never have I done that since...

 

[Lndwarrior]

Just wait until you accidentally leave a seatbelt that is not in use hanging out the door...

I did that once as a student pilot on a solo flight. Never have I done that since...

I did that already. It was the first flight I took my sister on. Sounded like a machine gun hammering the plane.

 

[Daleandee]

Just wait until you accidentally leave a seatbelt that is not in use hanging out the door...

I did that once as a student pilot on a solo flight. Never have I done that since...

I forgot my seatbelts once as we were quickly departing a fly-in event. I had a lot to do and then get into the line of planes leaving. It was butter smooth at 6500 feet. But when I descended to get under the approaching clouds it started to get quite bumpy. I reached to snug up the belts and realized I had not put them on.

We are humans and we will make errors. Learn from it and move on. Not learning from it means it may be time to consider tossing in the towel.

 

[Mikey52]

Deadsticked a 182 one time for carb ice. I had pulled the knob, but the flap to the actuating rod had come disassembled. Didn't realize it till I had slowed to taxi speed and engine stopped turning. It was middle of summer about 88 degrees outside. After sitting for 5 minutes or so, I fired it up and taxied to parking spot.

 

[rangerz]

Got it for the first time in the PA-24-250 a coulpe months ago. Clear but high humidity and around 40F. Noticed the MP was about 2" lower than what I set it. Pulled the heat and within seconds got back the 2" of MP. Of course that had me pulling heat every little bit the rest of the flight.

 

[Zeldman]

Sounded like a machine gun hammering the plane

I thought the cowling had come loose and was in the prop. A real hair raising event for sure.!!

 

[bkspero]

My only carb ice experience was in a C-150 during 6+solo practice maneuvers prior to my private pilot checkride. Doing power off stalls at about 3000 ft AGL under early spring overcast and the plane just didn't want to stall. I spent much more time than I should have with the throttle closed and carb heat on while the plane mushed through the air. Finally I jerked the yoke back, forced a stall, and when I opened the throttle...nothing.

Went through all the checklist items with no response. I'm convinced that the exhaust system had cooled sufficiently during the power-off maneuvering that carb heat wasn't doing enough to prevent carb ice.

After the eternity it took for the plane to descend to about 1000 ft AGL and for me to settle on the field I would use for my off-airport landing, the engine roared to life on its own. The FBO told me that they could find nothing wrong with the plane, and that it must have been carb ice.

 

[455 Bravo Uniform]

I think some of what happens in real life with the shock of actually needing carb heat (and using it as a first reaction) is related to training.

I used carb heat in training as a preventative, rather than a cure. We never experienced carb ice in training to be able to demonstrate carb heat and use it. So it just becomes a rote flow and checklist item on landing and during the run up check.

Don’t beat yourself up. But maybe consider it as an item that you memorize as a flow in your emergency checklist: fuel selector, mixture, CARB HEAT, ignition, primer. Treat a rough engine as an emergency and diagnose it with the flow/checklist.

You learned, and you taught (me at least). Keep flying.

 

[chemgeek]

Checklist, checklist, checklist. Memorize your engine anomaly checklist and/or panel flow. You just had a reminder.

I had a total engine stoppage (likely due to carb icing) when returning from an IPC in actual conditions in winter, complete with a thin layer of icy lake-effect clouds. A CFII and I were in the clear, returning to home base, with no obvious warning signs, when the engine just...stopped. Best glide, pick out a landing site, switch mags, full rich, carb heat, switch tanks, going right across the panel. The engine roared back to life in about 30 seconds with about 1000 feet of altitude to spare, likely due to carb heat melting carb icing.

Regrettably, we had a fatal fly a rental out of our airport, likely encounter with carb icing on a clear fall day, (apparently) didn't respond well to a sputtering engine at low altitude while sightseeing, and managed to spin it in to a large field suitable for an emergency landing. Proper systems knowledge and engine anomaly response would have probably had a different outcome.

 

[Shepherd]

My Continental C-85-8 made more ice than a Fridgidaire freezer.
I know it did. There was only one page in the POH, and it said "Always use carb heat when taxiing and landing."
I got distracted one morning and forgot to put my carb heat back on after my run up.
Three minutes and twenty four seconds later I was sitting on the side of the runway. That's how fast carb ice can form.

(So did all the Cubs, BTW.)

 

[Dan Thomas]

My only carb ice experience was in a C-150 during 6+solo practice maneuvers prior to my private pilot checkride. Doing power off stalls at about 3000 ft AGL under early spring overcast and the plane just didn't want to stall. I spent much more time than I should have with the throttle closed and carb heat on while the plane mushed through the air. Finally I jerked the yoke back, forced a stall, and when I opened the throttle...nothing.

Went through all the checklist items with no response. I'm convinced that the exhaust system had cooled sufficiently during the power-off maneuvering that carb heat wasn't doing enough to prevent carb ice.

After the eternity it took for the plane to descend to about 1000 ft AGL and for me to settle on the field I would use for my off-airport landing, the engine roared to life on its own. The FBO told me that they could find nothing wrong with the plane, and that it must have been carb ice.

The airplane's POH has some really smart stuff in it. For example, from a C150 POH:



That second item: Carb heat ON.

In the flight school, we reversed those first two. Carb heat on, RIGHT NOW. That exhaust system is made of some real thin stuff that cools quickly, and if one fools around too long establishing a glide speed, it might be too cool to provide any carb heat, and now you're in bigger trouble. It only takes a fraction of a second to get that carb heat on, too.

From the Canadian Flight Instructor Guide:

(3) Emphasize that the rate of carburettor ice formation varies widely and that there is a "point of no return" where there will be insufficient heat to remove ice. Therefore, encourage the student to check frequently for presence of ice. A slow rate of ice formation may go undetected while practising exercises involving power changes or when student's attention is concentrated on other matters.

(4) Refer to the Pilot Operating Handbook for information concerning use of partial carburettor heat in very cold weather and risk of raising carburettor air temperature to critical icing range.

(5) The student should be encouraged to make qualitative decisions daily before each flight as to whether the right conditions exist for carburettor ice formation, and if so, how severe it may be.

We used to teach the use of carb heat in any approach, any slow flight, and any practice of stalls or spins. It tends to reinforce, in the student's mind, the risks of carb ice. In the recovery from such maneuvers, the power was always brought back up first, then the carb heat was turned off. It helps to prevent stumbling if the engine has cooled off. Also, In any practice forced approach, the throttle was opened for five or ten seconds or so every 1000 feet of altitude loss, to prevent too much engine cooling and to get the exhaust system hot enough to keep carb heat effective.

Deadsticked a 182 one time for carb ice. I had pulled the knob, but the flap to the actuating rod had come disassembled.

A symptom of poor maintenance, running stuff until it fails. Not inspecting critical systems very well at all. We used to replace engine control cables at every engine replacement or overhaul. Cheap insurance.

 

[midlifeflyer]

You have no big claim to beating yourself up. I spent an entire night awake dong nothing but. I've had only one carb ice incident but it was a good one. IFR and in the clouds over the Rockies

Classic: visible moisture, temperature in the 70's F. Right about the red arrow. The green arrow is where we ended up landing. The engine never quit completely, but we were only able to generate 11" MP. I delayed applying carb heat (the reason is part of "the rest of the story") long enough that by the time I did, there was not enough heat to do anything. Power returned once we were out of the clouds.

My wife was with me.

 

[Ghery]

The only time I remember getting carb ice was in a 182. The engine kept looking power. I finally added carb heat and after the stumbles went away we never had a problem again. Carb heat early, carb heat often.

 

[Albany Tom]

Some planes make ice really easily. I think anything with a carb will do it in the right conditions. I've had it happen two different times in this area in Cherokees. I think some pilots don't notice it, if it's gradual. Just a little RPM drop at first, no big deal. At that stage it's easy to fix. I learned at a place with Cubs, they are ice makers, so it was drilled in to use carb heat always on approach, almost always on descents to the airport, and to always watch for it in cruise. Set your cruise RPM and don't play with the throttle. Drops 50 rpm? How come?

To the OP, I wouldn't beat yourself up too much. You won't miss carb heat again. But suggest adding looking at that checklist thing, as suggested above.

 

[Robert Rice]

I've been flying recreationally for over 30 years. Mind you 20 of those was pretty much the same 1 hour flight.

I'm on multiple aviation forums every single day, multiple times, for years now. I read all the accident reports. I use checklists (mostly). I am extremely safety conscious.

And today I was (mostly) an idiot - and my precious wife was in the plane.

Plane is my homebuilt Zenith CH601 XLB with an Lyco O-235-C1 engine, MA-3A carb, dual electric fuel pumps. I've put almost 600 hours on on her.

Today, wifey and I decide to take a scenic flight over the foothills of the Sierras where we live. We take off from Pine Mountain Lake (E45), marvel at the snow-capped Sierra's in the near distance, and cruise over Don Pedro Reservoir around 5000 feet agl.. Plane is running great in the cool, smooth air. The foothills are green and beautiful. I practice some slow flight as we head toward Calaveras County Airport and decide to do a landing. Prior to landing I pull the carb heat, as always, and make a decent landing.

We take off again, heading back to E45, with the power set at 2450 cruise rpm. We're up about 4000 agl just past Columbia Airport when I get the feeling the engine is running just a little rough. Am I imagining this? I pay more attention and it does seem like its running not quite right. So push the throttle in watching the tach to get it up to 2600 rpm or so. There's a slight stumble, but zero rpm increase.

I pull the throttle back and then forward again and the same thing happens. The engine does sound a little rough (though my wife did not notice it) but there is definitely something wrong with the engine. I pull the power back to 2400 and it seems reasonably smooth.

Yeah, with the clouds forming below us, temps in the low 40s, every damn rookie pilot in the world is thinking, "Pull the carb heat, idiot!".

Guess what I didn't do???

Well, I wasn't a complete idiot because all I thought about at that point was that we were within gliding distance of Columbia Airport. I rolled the plane into a 180, forgot to change to the airport frequency (Bro! You're on Guard!). F**k, mistake number 2. Change to the airport frequency and announce my position. The engine is running smoothly at this point and I dont touch anything until we're high abeam the numbers and know I have the runway made.

I landed long (telling wifey, I am NOT coming up short!) and pulled off the runway. Did a full power runup, no issues. Check both mags, no issues. Checked EGT and CHT (in the air beforehand as well), no issues. Check the fuel pressure, no issues. We sat there for a while, did a long taxi, another full power runup and no issues. AND I STILL DIDN'T THINK OF CARB ICE!!! Don't ever fly with me, I'm an idiot...

E45 is about 20 miles from Columbia so I make the decision to climb up to 7500 msl above Columbia Airport before heading back to E45. I want as much altitude in case something goes wrong.

I decide that a straight in to runway 09 at E45 is going to be the shortest route to getting on the ground. I stay up way high until 3 miles out then I pull carb heat before reducing the throttle - and the friggen light finally goes off in my brain - carb ice.

I'm still beating myself up wondering how the hell this didn't cross my mind beforehand. It's no excuse, but in 30 years of flying I've never experienced carb ice.

Yet, I still can't understand why that wasn't the FIRST thought on my mind? I am getting older and maybe this is a sign that it's time for me to reconsider continuing with this passion of mine. I just see no way of letting myself off the hook for this.

If I had been flying by myself, I may not be so concerned about my actions, However, my precious wife was in the plane and she deserves a better pilot than this. What if we hadn't been in gliding distance of an airport and it had got worse and I still didn't recognize it?

I have some serious thinking to do.

( I will be checking my fuel system just in case. There is a slight chance a temporary blockage of some kind could have caused this.)

There are a lot of stories like that! I was flying a 172 out of KTPF the other week with MY wife. Did a pre-flight inspection, used the check-list, all the normal stuff. On the take-off roll the tach showed "normal" which doesn't really mean anything in a 172. During climb out, the performance was poor and the engine a little rough. When I continued climbing turn back to the airport (to land), we went through the "emergency" checks: carb head (off), fuel on both, mixture rich, throttle in, mags check - THAT IS WHERE I FOUND THAT I WAS ON ONE MAG. During the pre-take-off mag check, when I thought I had moved it key to the "both" position, it didn't quite click over (apparently) and I did NOT notice the LACK of tach change. My bad. Good thing I did NOT turn on carb head during the climb out or we might not have made it back to the airport! We live and learn. I learned NOT to touch the carb heat unless conditions indicate and consider checking the mags first. Anyone know where I can find a Zenith guru to help inspect a 601XL in Michigan?

 

[nrpetersen]

Doesn't anybody teach to combine carb heat with mixture adjustment to raise the EGT to avoid losing the engine altogether? I also see the recommendation from the Cessna (?) operating manual is to go full rich which would just make severe carb icing worse.

Or is it just because of my experience & expectations with small engines?