Jump to content

Summmer Leaning on Approach


Recommended Posts

1 hour ago, neilpilot said:

If you use carb heat on all large power reductions in all weather, it becomes a routine that you are less likely to forget when the weather requires.  I've read several times about a carb icing incident in weather that wasn't expected, that surprised the pilot?  I don't need that kind of surprise.

Do you fly using a landing checklist?  Do pilots who fly behind a O360 use a checklist that says, "apply carb heat only in the following weather:  xxx temp and yyy humidity range"? 

I am more of a big picture person. BTW I do not have a carburetor. :-) 

Just find this talk entertaining 

Link to comment
Share on other sites

2 hours ago, Mooney1 said:

Always shake my head at the people that use carb heat in the summer.  Or in conditions that do not require it. WHY???!!!

 

Carb heat is called for under certain conditions by the POH for those without carb temp gauges regardless of season.  There is a reason for that.

Carburetor ice can and does occur on hot humid summer days.  Do not confuse carburetor ice with structual icing....different animals.  The NTSB files are full of off-airport landings during the summer attributed to carburetor ice.

When carb heat is applied, it effectively richdens the mixture.  Compensate with that red knob...the engine smooths out nicely.

Carry along a carb ice probability chart.

  • Like 2
Link to comment
Share on other sites

5 hours ago, Mooney1 said:

Always shake my head at the people that use carb heat in the summer.  Or in conditions that do not require it. WHY???!!!

 

You been caught...:)

See if this answers your why question... 

1) Because icing happens in carbs even in the summer... during seasons and weather, when it is unexpected... by head shaking people.

2) Without a carb temp probe, it is near impossible to tell what’s going on inside the carb... the extra sensor is not very expensive anymore... it was once. Expensive and rare...

3) There is also an ice sensor that kind of works, but not a good substitute for carb temp...

4) Without carb temp it is impossible to modulate the carb heat... the safe procedure is either heat on or heat off...

5) Selecting carb heat on, immediately robs about 10% of the available hp as the air density decreases with temp... a not very good alternative when fully loaded over harsh terrain bounded by clouds overhead...

6) The alt air source is not clearly marked either... using carb heat, automatically is the alt air source as well.

7) the source of the cold temperature is the fuel evaporating in the vacuum of the carb Venturi....and the decrease of the air pressure in there too...

8) the source of the moisture is often high relative humidity found beneath cloud layers... it doesn’t need to be raining...

9) it is hard to find icing.  It is not a common occurrence.  But, when it finds you, you want a procedure to execute....

 

So... you get a pass for not knowing about carb ice.... flying a carb free engine... (your not out of the frozen woods yet... wait there’s more...)

 

But...

You know what kind of ice effects the IO360 instead?

We have one MSer that ran into an icing challenge in his J over the North Sea...   that’s a pretty cold place to have an engine losing power due to ice ingestion...

That MSer can probably write a dissertation on alt air system maintenance...

Please sense my sense of humor... and the seriousness of intake icing for all planes...

There is always going to be a condition that icing can occur.  Unless you stick to perfect weather flying only...

 

PP thoughts only, sprinkled with bits of humor the best I can... :)

Best regards,

-a-

  • Like 4
Link to comment
Share on other sites

I only put 400 hours on my C. But in that time I never had carb ice in any conditions. The only time I pulled the carb heat on other than during the runup, was on the rare occasion I used a smidge of it to get better fuel distribution for LOP. 
I'd never use carb heat. Secondly, I'd never go full rich in the pattern. I'd generally leave the mixture alone all the way to the ground. Of course, if I need to go around, the black and red knobs will go full forward together.


This is my experience as well with 700 hours in my C. I don’t use carb heat except to test it during the run up, and also don’t go full rich while landing.


Sent from my iPad using Tapatalk
  • Like 1
Link to comment
Share on other sites

Another C with minimal carb heat use. Test right aftet engine start per checklist, almost zero use after that, except for a couple of flights in IMC where my carb temp gage was close to freezing.

But I do go full rich in the pattern, and lean hard when slow and under good control on the runway. About 2/3-3/4 towards Idle Cutoff, enough that I must enrich to taxi uphill. 

I don't need carb heat on descent because I don't reduce power until slowing down for pattern entry, just periodically walk throttle back and mixture forward to maintain my cruise settings for MP and EGT. Easy peasy, no carb heat required.

Link to comment
Share on other sites

DMax told me when I first bought my C that O360's are ice machines except when wrapped in a Mooney cowl. They just don't seem to make ice in Mooney's like they make in other brands. 

But then again, my before landing checklist is just Gear. Everything else is as required.

Link to comment
Share on other sites

1 minute ago, gsxrpilot said:

DMax told me when I first bought my C that O360's are ice machines except when wrapped in a Mooney cowl. They just don't seem to make ice in Mooney's like they make in other brands. 

That's because our carbs are mounted to the oil pan, which is a warm place during flight.

Link to comment
Share on other sites

I'm flying an IO-360, so I'll only comment on leaning.  I have found that leaving the engine leaned to peak or LOP from cruise all the way down to landing results in a smooth running engine with little chance of fouling. descending from cruise altitude, I will only touch mixture if any roughness occurs...   once on the ground, I give a few more twists to further lean to where it is near cut off..  keeps the engine happily purring.

Link to comment
Share on other sites

I'm flying an IO-360, so I'll only comment on leaning.  I have found that leaving the engine leaned to peak or LOP from cruise all the way down to landing results in a smooth running engine with little chance of fouling. descending from cruise altitude, I will only touch mixture if any roughness occurs...   once on the ground, I give a few more twists to further lean to where it is near cut off..  keeps the engine happily purring.


I’ve never had an issue leaving the mixture slightly lean when setting up to land. Nor I have ever had an issue leaving it rich with reduced power (including flying for years with massive spark plugs).

The only caveat on leaving the mixture lean in our IO-360s is if you are flying an instrument approach and need to execute a missed approach.


Sent from my iPad using Tapatalk Pro
Link to comment
Share on other sites

2 hours ago, Marauder said:

 


I’ve never had an issue leaving the mixture slightly lean when setting up to land. Nor I have ever had an issue leaving it rich with reduced power (including flying for years with massive spark plugs).

The only caveat on leaving the mixture lean in our IO-360s is if you are flying an instrument approach and need to execute a missed approach.


Sent from my iPad using Tapatalk Pro

 

Right, if on an approach, then I go full rich if I haven't broken out before about 200-300ft above DA..  power on approach with full rich seems ok..     it's the power off full rich that seems to cause build up. 

  • Like 1
Link to comment
Share on other sites

11 minutes ago, Browncbr1 said:

Right, if on an approach, then I go full rich if I haven't broken out before about 200-300ft above DA..  power on approach with full rich seems ok..     it's the power off full rich that seems to cause build up. 

I've been going full rich within 1 nm of my destination, at low power trying to get below 100 mphi, for a decade. I also lean very aggressively on the ground. there is virtually zero lead buildup on my plugs when I check them at annual, and at oil changes when I have time and remember.

  • Like 2
Link to comment
Share on other sites

Coming into Heber City in July (DA 9500') in my E, I went full rich out of habit and it felt like it was flooding the engine. Only had a single probe EI digital EGT gauge, so I just kinda guessed at best power, but I leaned quickly and got the engine back to purring.

Operating at Big Bear the other evening, DA 7500', I leaned to best power on the ground with full power during the run-up (left it leaned from cruise flight during the approach), and the difference was noticeable (now in an M20F). Definitely lean at higher DAs; 5000' is where I would start to seriously consider it.

Edited by chrixxer
  • Like 1
Link to comment
Share on other sites

On 5/13/2018 at 8:30 PM, gsxrpilot said:

DMax told me when I first bought my C that O360's are ice machines except when wrapped in a Mooney cowl. They just don't seem to make ice in Mooney's like they make in other brands. 

Cherokees rarely need carb heat... O-320s and O-360s. POH calls for carb heat only as required, not as a matter of course.

Link to comment
Share on other sites

A lot of test pilots on this thread.

I like the idea of applying with checklist BECAUSE:

-Like a seatbelt, you never know when you will need “it” and after is too late.

-Carb ice is an uncommon event, but low and slow reacting vs. being preventative-CONSISTENTLY is good medicine.

  • Like 1
Link to comment
Share on other sites

2 hours ago, MyNameIsNobody said:

A lot of test pilots on this thread.

I like the idea of applying with checklist BECAUSE:

-Like a seatbelt, you never know when you will need “it” and after is too late.

-Carb ice is an uncommon event, but low and slow reacting vs. being preventative-CONSISTENTLY is good medicine.

That's why the (optional) Carb Temp Gage is so nice to have . . . .  :D  Mine is right next to the EGT. 

Edited by Hank
Link to comment
Share on other sites

11 hours ago, RLCarter said:

The use of Carb Heat during landing is to prevent Carb Ice, waiting until you need it when low & slow isn't a place you want to be. 

If I'm low and slow, the runway is made with or without the fan on the front running. 

  • Like 1
Link to comment
Share on other sites

Both of my airplanes have carb temp gauges.  Part of my approach routine is a glance at the gauge.  If in the yellow or colder it gets carb heat.  If warmer than that I leave it alone and avoid feeding unfiltered air when not necessary.

Link to comment
Share on other sites

On 6/16/2017 at 6:24 AM, steingar said:

Haven't used carb heat much since I flew a Cessna 150.  I certainly would if there were visible moisture anywhere.

Worst carb ice I got was in the summer on a clear morning. Visible moisture isn't a great indicator

 

https://www.aopa.org/training-and-safety/air-safety-institute/accident-analysis/featured-accidents/epilot-asf-accident-reports-carburetor-what

 

-Robert

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.