Use of Carb Heat

[minitour]

That really doesn't make sense to me. All of the cessnas I'veflown have had Lycoming O-235 or O-320 (plus an IO-360 but thatwouldn't apply here) in them. How would that differ from thePipers?

-mini

 

[BD King]

Blah, Blah. Listen to AvBug.

.Now here is the question. You have carb ice and cannot get rid of it. What do you do? AvBug, you are not allowed to reply.

 

[SiuDude]

That really doesn't make sense to me. All of thecessnas I'veflown have had Lycoming O-235 or O-320 (plus an IO-360 butthatwouldn't apply here) in them. How would that differ from thePipers?

-mini

It wouldn't. Lycoming equipped Cessnas are less succeptible to carbice. However, if the conditions are perfect, any carburetor willdevelop induction ice (I've seen it first hand). It just may come as abigger surprise in a Lycoming.

 

[SiuDude]

Blah, Blah. Listen to AvBug.

.Now here is the question. You have carb ice and cannot get rid of it.What do you do? AvBug, you are not allowed to reply.

Lean the engine to "best economy?" If that doesn't work, make lemonade?

 

[minitour]

It wouldn't. Lycoming equipped Cessnas are lesssucceptible to carbice. However, if the conditions are perfect, anycarburetor willdevelop induction ice (I've seen it first hand). It justmay come as abigger surprise in a Lycoming.

oh okay...now I get what you were saying...misunderstanding on my part...

my bad

-mini

 

[avbug]

.Now here is the question. You have carb ice and cannot get rid of it. What do you do? AvBug, you are not allowed to reply.

Must...not...answer. Trying...very...hard. Cannot...hold...out...any...

Pick something soft to land on. Use a rubber band to hold the control yokes together, crawl out on the cowl and use a squirter bottle in the induction intake to apply glycol. Think warm thoughts. Increase angle of attack until aircraft stalls, apply hard rudder (right or left), enter spin and hold it until impact. Everyone knows that when the engine quits a spin always results and always ends in a fatality. With a big fireball at the end. A really big one.

Or you could just shut it off and let the ice melt...stopping airflowthrough the carb removes the very thing that's causing the ice to form...

Of course, you're probably thinking about causing a backfire to clear the carb. Personally, I'm against that action for several reasons, but suffice it to say it's not a good idea. If you've no other choice, then one does what one must. But in general it's not a good idea, and certainly shouldn't be performed unless you have no other choice. If you're put in the position where a forced landing is going to result in damage anyway, and you're not going to recover that engine, and it's your only one (or your last one, as the case may be), the have at it. Open the throttle and lean her out until she bangs away, or lean her and throw the throttle open. Give her a shot or two of primer first and then open at the same time while running lean. A little like you probably used to do to scare folks while cruising mainstreet in dad's pickup truck.

You did do that, didn't you? Or is that too redkneck for most folks?

 

[nosehair]

like you probably used to do to scare folks while cruising mainstreet in dad's pickup truck.

You're talkin' when they had "clutches", arentcha?

 

[BD King]

AvBug is correct. When there is no choice, backfire through the carb. Flip the mags off and turn them back on. Does it work? Yeah. I had a load of carb ice in a C-140 and could not get rid of it (cable came off). It was stick it in a field. Back fire worked.

 

[minitour]

You're talkin' when they had "clutches", arentcha?

LOL

Funny story. From the student pilot days.

Told my Aunt "yeah I have to get more comfortable at doing stalls in the airplane."

She says, "It's easy, just pop the clutch and the engine will start right up"

I must have stared at her for 10 minutes with that "you're f*cking kidding me, right?" look on my face...

 

[A Squared]

AvBug is correct. When there is no choice, backfire through the carb. Flip the mags off and turn them back on. Does it work? Yeah. I had a load of carb ice in a C-140 and could not get rid of it (cable came off). It was stick it in a field. Back fire worked.

That's not a backfire, that's an afterfire. A backfire is an ignition of fuel air mixture in the induction system. What you get if you turn the mags off and back on is an explosive ignition of unburned fuel air mixture built up in the exhaust system. It is very unlikely to do anything to the carburator, Ice or no ice. It very likely may damage your exhaust system though. When I was a foolish kid, I thought it was pretty cool to do this with my dad's pickup truck, until I blew the muffler up. Looked like someone had lit off a cherry bomb inside it. My dad was not amused. Anyway, although this is sometimes incorrectly referred to as a backfire, it is in fact not.