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Carb Air Temp Eng gauges in white sector and the AFE

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Hello :smile:

 

In cruise flight, for example, if the Carb Air Temp Eng gauges (No. 315-318 on the POH Manual, page 47) indicates a value below the yellow area, I apply the necessary corrections with the 4 Carburetor Air Eng levers (No. 401-404 on the POH Manual, page 41), but if the AFE is active, it automatically lowers again the 4 levers at full down, which lowers the temperature below the yellow sector again (in white sector)... what is not acceptable for the carburetors.

To solve this problem, I have to disable the AFE when he finished the current checklist and adjust the 4 Carburetor Air Eng levers to obtain a temperature value in the green sector of the Carb Air Temp Eng gauges. But as soon as I activate again the AFE for another checklist, it lower again at full down the 4 levers ... and I have to make again as previously mentionned.

Question : would it be possible when the AFE is active, it leaves the setting of the the 4 Carburetor Air Eng levers adjusted by the user ?

 

-----

Jean-Pierre Richaume

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In cruise flight, for example, if the Carb Air Temp Eng gauges (No. 315-318 on the POH Manual, page 47) indicates a value below the yellow area, I apply the necessary corrections with the 4 Carburetor Air Eng levers (No. 401-404 on the POH Manual, page 41), but if the AFE is active, it automatically lowers again the 4 levers at full down, which lowers the temperature below the yellow sector again (in white sector)... what is not acceptable for the carburetors.

 

Major simism.

 

This is perfectly fine for the carburetors. The yellow sector is the only time where you will find any appreciable risk of carb ice, firstly. Secondly, ice requires both cold and water. If the air is simply cold, then it's entirely a non-issue. The AFE is taking the correct action by countering your incorrect action, which would cost you aircraft performance for no reason.

 

I know it might seem logical on the surface, but instead of assuming we programmed the AFE as a bunch of guys who have never flown classic aircraft like this, consider for a few moments that we're probably several steps ahead of you  :wink:

 

 

 


Question : would it be possible when the AFE is active, it leaves the setting of the the 4 Carburetor Air Eng levers adjusted by the user ?

 

No. Particularly in this case, there's no need.

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Thanks Kyle for the answer :smile:

 

So, it's acceptable if the air is not cold and very humid at once.

 

-----

Jean-Pierre Richaume

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So, it's acceptable if the air is not cold and very humid at once.

 

As long as it is out of the yellow band, yes.

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Thanks Kyle :smile:

 

With the settings made by the AFE it's OK , so I can fly without worries :

Is the air humidity managed by X-Plane... and known by the AFE ?

 

646674CarbHeat.jpg

 

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Is the air humidity managed by X-Plane... and known by the AFE ?

 

Yes and yes.

 

What was your free air temp during this time?

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I did not notice the free air Temp at this time.
 


I'll test again and I'll post screenshots ...
 
-----
Jean-Pierre Richaume

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In cruise flight, at 12,000 feet, 215 kt.

http://img11.hostingpics.net/pics/383578CockpitDC6.jpg

 

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- The AFE is active : cruise checklist done.
- Ground temperature : 7° C
- Free Air Temperature : -20° C
- Car Air Temperature : -40° C (due to the venturi effect)
- Air humidity : I don't know

The AFE maintains the four levers down for the heat carburators ( but what is the air humidity ?... I don't know. Maybe the air is not sufficiently humid to be freezing ...... )

 

311537CarbHeat.jpg

 

-----

Jean-Pierre Richaume

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The AFE maintains the four levers down for the heat carburators ( but what is the air humidity ?... I don't know. Maybe the air is not sufficiently humid to be freezing ...... )

 

Doesn't matter. If free air is -20 the potential water is already frozen...

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Ok, thank you Kyle for all this informations :good: 

The functioning is OK, so I have not to worry :smile:

 

-----

Jean-Pierre Richaume

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Ok, thank you Kyle for all this informations  
The functioning is OK, so I have not to worry

 

Welcome!

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Is it then correct to assume the AFE is handling the carb heat controls so as to avoid carb ice?

 

I just flew through known icing conditions with the AFE active, and my engines did indeed ice-up and the carb-ice warning was displayed.  Two engines failed due to carb ice (I wanted to see if the AFE would allow this to happen).  He did.

I could NOT adjust the carb heat controls as long as the AFE was active.

 

Do I misunderstand the AFE duties here?  With what you've said in this thread I thought this couldn't happen.

Thanks,

 

Jerry Allen

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Is it then correct to assume the AFE is handling the carb heat controls so as to avoid carb ice?

 

Yes.

 

 

 


I just flew through known icing conditions with the AFE active, and my engines did indeed ice-up and the carb-ice warning was displayed.  Two engines failed due to carb ice (I wanted to see if the AFE would allow this to happen).  He did.

 

What were the conditions, specifically. If you're trying to point something out, then please provide all the information required for us to reproduce the issue to potentially chase it down.

 

 

 


I could NOT adjust the carb heat controls as long as the AFE was active.

 

Shut the AFE off if you need manual control. There's a reason the Abort button is there.

 

 

 


Do I misunderstand the AFE duties here?  With what you've said in this thread I thought this couldn't happen.

 

It depends on a number of things. Had you provided more information, I could better address your points, but without additional information, there isn't much I can say.

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Kyle,

 

I don't have more information at this time because once again you say "YES" to the AFE guarding the carb-heat and not allowing this to happen.  Yet, further down your post, you say "It depends on a number of things". 

Well, which is it. YES or NO?

If as you say, it depends on other things, then what are those things?  If you would provide more information perhaps I would have a better understanding of what the AFE is doing in regards to carb-heat.

Thank you,

 

Jerry Allen

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