Flaps and Carb Heat on Landing Rollout

WDD

WDD

Final Approach
PoA Supporter
Joined
Oct 16, 2019
Messages
6,168
Location
Atlanta / Marietta
Display Name
Display name:
Vintage Snazzy (so my adult children say)
My PPL CFI instilled in me to immediately raise the flaps and turn off carb heat - in that order- after touchdown in case had to take off again.

A recent flight with my CFII ( different instructor) had her comment that I shouldn’t touch anything until clear of runway. Someday might flip up the gear handle vs flaps.

I see merit in both. Thoughts?
 
One CFI I flew with said to use your pinky to put up the flaps. Because gear switches tend to require two actions (e.g. pull out before pushing up), it is unlikely for you to be able to do that with your pinky.
 
Personally I wait to retract flaps until I'm clear of runway and at my tiedown or hangar.
 
AKBill said:
Personally I wait to retract flaps until I'm clear of runway and at my tiedown or hangar.
Click to expand...
Cool. But I’ve also been told to avoid taxiing with flaps - although CFI not sure why. Maybe afraid of tires tossing debris into flap system??
 
WDD said:
My PPL CFI instilled in me to immediately raise the flaps and turn off carb heat - in that order- after touchdown in case had to take off again.
Click to expand...

I'm trying to think of the case in a light airplane where, once landed, and apparently rolling for at least a little bit, it would make sense to take off again instead of just stop.

The number of realistic scenarios for that must be really small.
 
I think that's good advice depending on what and where you're flying.
My runway is kinda short and my flaps are attached to a bar on the floor. Its a Cherokee. So in order to get weight on the mains to start to slow down the plane I dump flaps almost as soon as I hit the ground.
 
WDD said:
Cool. But I’ve also been told to avoid taxiing with flaps - although CFI not sure why. Maybe afraid of tires tossing debris into flap system??
Click to expand...

Having your flaps down does make you more susceptible to gusts. And in a Cessna, having the flaps down while taxiing does limit your visibility to the rear.

Leaving flaps down after landing used to be a signal to ATC that you were being hijacked. I don't think that's true any more though.
 
Neither are right, neither are wrong. You should do what is in your comfort level.
 
I like flaps up after touch down in the tailwheel. Carb heat gets turned off on short final ...
 
I dump the carb heat during roll out.

In the Cherokee I retract the flaps right after the carb heat, but in the skyhawk I tend to wait until clear of the runway just because I need to keep my hand on the switch as the flaps retract. Just a comfort level thing...
 
A school near us had a couple of Twin Comanches. Students busted both of them by raising the gear right after touchdown, grabbing the gear lever instead of the flap switch. They had been taught, in the 172s, to raise the flaps in the rollout, and it bit the school. Depending on where the squat switch is located, and the airspeed and attitude in the rollout, it's easy enough to wreck the airplane. And while checking out a pilot candidate, another instructor in our school had to quickly slam the gear lever down when the pilot raised it instead of the flap switch. The pump was already running and the nosewheel would have been unlocking. Very, very close. R182. The candidate had been briefed to leave the flaps alone until stopped, but Primacy took over and he unconsciously went for them. Primacy does a lot of damage when bad habits are picked up early on.

So we taught students to leave the flaps alone until the airplane was stopped. In the 7GCBC, though, flaps down in the rollout in a crosswind landing made things difficult, so we'd retract them, but it was a big manual lever on the left, not a switch on the panel on the right. The right hand wasn't learning any bad habits.
 
No flaps.
But in the PA-17 you have to taxi with carb heat or it will ice up.
It happened to me while taxiing back in mid-May.
 
My Beech even has a placard to raise the flaps on rollout in order to improve braking so that's what I do, just as soon as the wheels are rolling. Since the gear is welded down there's little risk, though it seems to be a bit common for Bonanza drivers to hit the gear switch instead of the flaps. Carb heat is typically off in the pattern anyway.
 
I try to impart that rarely is there any urgency to do anything during the rollout - but pilots almost universally show a tendency to want to fidget with stuff that can usually wait.

From the Airplane Flying Handbook:

To give full attention to controlling the airplane during the landing roll, the after-landing checklist should be performed only after the airplane is brought to a complete stop beyond the runway holding position markings. There have been many cases where a pilot has mistakenly manipulated the wrong handle and retracted the landing gear, instead of the flaps, due to improper division of attention while the airplane was moving. However, this procedure may be modified if the manufacturer recommends that specific after-landing items be accomplished during landing rollout. For example, when performing a short-field landing, the manufacturer may recommend retracting the flaps on rollout to improve braking. In this situation, the pilot should make a positive identification of the flap control handle before retracting the flaps.
 
WDD said:
in case had to take off again
Click to expand...
what's the real world scenario of this actually having to happen again.. and there being enough runway left to make it? The situations I've heard of were people attempted to take flight again did so because they landed late, realized they couldn't stop, and tried taking flight again - usually with poor results

WDD said:
I shouldn’t touch anything until clear of runway
Click to expand...
that's how I was taught and the way I do it. If the runway is that tiny that I need to dump the flaps on touchdown to get an extra 50 feet of stopping power then I'll plan for and prepare specifically for that landing. Otherwise I "clean up" when clear of the runway. How much lift is a wing at 0* angle of attack going 45 knots really generating anyway..?
 
These are techniques, not procedures. You've already stated some of the reasons why a pilot might use each technique. Understand the pros and cons of each and decide which technique works best for you.

Older cockpit designs didn't have as well though-out ergonomics and it was often easier to mistake the flap and gear switches than it is in more modern designs. The older Bonanzas with the "piano key" switches all in a row is a really good example.

Waiting until taxi speed to start reconfiguring, unless there is a compelling reason to do so sooner, it probably a good idea. What is your compelling reason to raise the flaps, or turn off the carb hear, sooner? Assess the threat each presents and determine the best technique mto mitigate those threats. The answer may be different in different airplanes or different flight conditions.
 
Flying retracts I usually teach don’t touch anything until off the runway. If reasonable I will land in a go-around configuration so a go around only requires adding throttle and perhaps re-trimming. Obviously this doesn’t work well in some planes or if performing a short field approach. I rarely do touch and goes in retracts.

Even in fixed gear I prefer landing in a go-around configuration. I usually do leave the Carb heat on, and part of my go-around procedure is to remove the carb heat. But I see a number of pilots that turn the carb heat off on short final in preparation for a potential go-around.

Brian
CFIIIG/ASEL
 
As a general practice I always retract flaps and turn off carb heat after touchdown. As others have noted raising flaps achieves maximum braking which in some circumstances can make a difference in a positive outcome.
 
WDD said:
My PPL CFI instilled in me to immediately raise the flaps and turn off carb heat - in that order- after touchdown in case had to take off again.

A recent flight with my CFII ( different instructor) had her comment that I shouldn’t touch anything until clear of runway. Someday might flip up the gear handle vs flaps.

I see merit in both. Thoughts?
Click to expand...

Your first CFI has me scratching my head.

Most pilots who practice retracting flaps on the rollout do so for max braking (puts more weight on the wheels).

Retracting on the rollout because ‘you might need to take off again’ doesn’t really make that much sense unless intentionally doing a touch and go.

I’m genuinely curious what situation (other than Maverick intentionally bolting to go save Cougar) would require you to take off again after touch down?

Go around should be initiated while still in the air. Trying to takeoff again for something like a runway conflict is asking for trouble IMO.

Same thing for planes that need carb heat during approach. Every CFI I’ve flown with advocates to push carb heat in on short final, again, in case you need to go around.

I’m generally in the camp of don’t touch anything until stopped clear of the runway, but I also fly a lot of those older non-human factors designed antiques.
 
I don’t disagree that it’s bad from a primacy standpoint, and I do have my complex endorsement, but I almost always retract flaps on roll-out in my simple 182 as a way to increase braking effectiveness merely as a habit for those times I’ll need it (good primacy response in my 182). Laughably, most of my landings are on paved 4000 ft or longer runways.
 
Carb heat off on short final. No reason to keep it on past that point. Flap retract depends on the situation. Rough field where I want to keep the tail up? Flaps stay out. Windy and want to improve control? Flaps retract immediately after wheels touch so the tail drops, it's done flying, and the brakes become the primary control. Average days? It doesn't make any difference.
 
Half Fast said:
My Beech even has a placard to raise the flaps on rollout in order to improve braking so that's what I do, just as soon as the wheels are rolling. Since the gear is welded down there's little risk, though it seems to be a bit common for Bonanza drivers to hit the gear switch instead of the flaps. Carb heat is typically off in the pattern anyway.
Click to expand...
Right on. I trained on these and later owned one. Just touch the brakes when the flaps are down and rolling out and you "flat spot" two tires. Its due to a low wing & airfoil that produces excellent lift flaps down, a stabilator (flying tail) that is really powerful when the yoke is forward and a fwd CG. You can, at times see about a foot of daylight under the mains when somebody pins the nosewheel after touchdown and flaps are still full down. This type also has a history of ground loops caused by an FAA term called wheel barrowing. Roll out with mains barely touching, flaps down, the nose wheel planted and a cross wind and she can spin around on the nose wheel. The FAA issued an AC years ago on this W.B. issue. It was canceled years ago but may still be available on the web site. It's a good thing that the flaps are manual and you can go to flaps up with the speed of a switch blade. I was taught from day one not to taxi with the flaps down in any type so that propwash debris doesn't damage the flaps.
 
Larry in TN said:
Waiting until taxi speed to start reconfiguring, unless there is a compelling reason to do so sooner, it probably a good idea. What is your compelling reason to raise the flaps, or turn off the carb hear, sooner? Assess the threat each presents and determine the best technique mto mitigate those threats. The answer may be different in different airplanes or different flight conditions.
Click to expand...

I may have mentioned before that I have a boatload of flight time in Alaska on and off of gravel strips. Most were 1500 feet or less, so braking is required on landings. As soon as the brakes are applied, the tires will be throwing rocks at the horizontal stabilizer. On a low wing those rocks will beat the snot out of the flaps, so it is imperative to get the flaps out of the way, meaning flaps up as the mains are touching down. Those rocks will reach the flaps on a high wing, so again, flaps up immediately.

So you are correct. There is no really right or wrong answer. What works for one strip or airplane may be totally different for another landing strip or airplane.

When I came to New Mexico and a 7000 foot paved runway, I had to totally relearn how to land... :lol::lol:
 
The flaps on a 172, for instance, generate the most lift and least drag for that lift at 20° flap. The electric flaps are slow, so retracting them from 40° to get better braking is almost a lost cause, as they pass through 20°and are still lifting, and you're losing the drag of the 40°.

You can get better traction just by holding the elevator full up. That forces the mains down harder. The 172 POH will tell you that.
 
Last edited:
WDD said:
My PPL CFI instilled in me to immediately raise the flaps and turn off carb heat - in that order- after touchdown in case had to take off again.

A recent flight with my CFII ( different instructor) had her comment that I shouldn’t touch anything until clear of runway. Someday might flip up the gear handle vs flaps.

I see merit in both. Thoughts?
Click to expand...

If I mistake the Johnson bar flap handle that goes to the floor for the gear switch that I have to reach behind my control wheel to engage, I probably shouldn't be flying anyway.

The Comanche likes to "skate" if the flaps aren't at 0 when applying brakes.
 
Right or wrong, I dump my flaps shortly after landing, at least in a johnson bar cherokee. It very effectively plants the mains.

The 172 has those godawful electric flaps, so I leave those alone for reasons touched on above. I do shove the carb heat in as soon as I can because that hot ultra rich mixture seems like a great way to foul a plug.

I rode with @kaiser in a saratoga he other day, which is the newest airplane I've been in. For some inexplicable reason they went to the stupid cessna style electric flaps on them. I could see how someone might mistake one for the other with that setup.

Seems like this is one of those "it depends" scenarios.
 
When I had my old Hawk XP in windy conditions I'd move the switch from 40* to zero while still a few feet above the ground. Solid touchdown and it allowed full aft elevator without the threat of becoming airborne again.
 
Since @Jim K tagged me, I suppose I should also answer the OPs question.

It depends.

I usually mess with config (I.e. flaps etc) only after I’m slow or off of the runway (below “airspeed alive” speed). On the landing rollout, I enjoy having loads of flaps out for aerodynamic braking. The one exception is if it’s super windy or gusty - anytime I’m worried about unintentionally taking off again - in which case I dump flaps on touchdown.

For carb heat, the only time I really rush to it is when I’m landing on contaminated runways (grass, gravel, rain/snow, etc)


Jim K said:
I rode with @kaiser in a saratoga he other day, which is the newest airplane I've been in. For some inexplicable reason they went to the stupid cessna style electric flaps on them. I could see how someone might mistake one for the other with that setup.
Click to expand...
Oh, and to directly respond to this, unless I’m flying a bush plane, there’s no need for Johnson bar flaps. As a pilot, I’m the commander..l and therefore manipulate the aeroplane to do my bidding. That includes selecting flaps and knobs, not fandangoing levers and gears.:cool:
 
Back when I had a plane with flaps (182RG), I shutoff carb heat and retracted flaps on rollout. If I mistake the flap lever or carb heat knob for the gear handle, I shouldn't be flying airplanes. ;)
 
One thing I have adopted to avoid touching the gear switch in either an airplane OR a helicopter is to tap on the N number plate and verbalize which flying machine I am operating at that moment and announcing whether it has retracting gear.

If it does, I put my dirty fingers on my head, or at least nowhere near the gear switch.

When you operate several flavors of aircraft, keeping track of flaps, wheels and mission equipment during the various phases of flight requires extra vigilance and mistakes (errors) can be painful and expensive.
 
In the Arrow I dump the flaps when I'm on the rollout. That, plus making sure the yoke is as aft as I can get it helps with aero-braking. Works in the Arrow. But others may behave differently. Don't have a carb to heat, so I don't worry about that.
 
My first (and best) CFI told me to push carb heat back in on final, in preparation for a potential go around, and to leave flaps and everything else untouched till clear of runway. One exception: short field landings where flaps go back on touchdown. It has served me well so far....
 
I always turn off the carb heat right after landing, if it was on in the first place (the Cherokee POH says only turn on carb heat during landing if signs of icing exist). Reason being, my CFI scared the heck out of me about all that dirty, dusty, unfiltered air coming into the engine with the carb heat on, I feel like if I keep it on for too long on the ground, my engine will explode. Flaps, I sometimes retract them on roll out, sometimes I wait until I’m clear and go through my after landing checks. It depends on how long the runway is, how long my roll out is, etc. sometimes I land on 8000 ft runways and tower tells me after I land to taxi to the end. That’s a long, boring taxi so I tend to clean things up while rolling.
 
EdFred said:
If I mistake the Johnson bar flap handle that goes to the floor for the gear switch that I have to reach behind my control wheel to engage, I probably shouldn't be flying anyway.

The Comanche likes to "skate" if the flaps aren't at 0 when applying brakes.
Click to expand...
I'd take it a step further and say that if I could mistake a flap handle with a gear switch on roll out, I'd do the same mistake once clear the runway (so what difference does it make where I make the mistake), and I probably shouldn't be flying anyway.

Oh and as far as an instructor that is against retracting flaps on rollout, I once had an instructor slap my hand as I was reaching to retract flaps on rollout, and as he did so he was saying that I would someday retract the gear...that day was also known as "the last day I flew with that $#@$#% instructor".
 
No carb heat (Rotax 915)

Leave flaps in in case of go-around.

At safe speed, drop flap lever to easily reach tailwheel unlock lever to exit runway.
 
Has a plane ever failed to execute a successful go-around because the carb heat was left on? I can't imagine it robs *that* much power
 
Tantalum said:
Has a plane ever failed to execute a successful go-around because the carb heat was left on? I can't imagine it robs *that* much power
Click to expand...

I heard in high compression engines like the Cherokee with the 160 HP, leaving the carb heat on at full power during a go-around could damage the engine due to detonations (not sure if that's the correct thing)... I don't know enough about this stuff - I just fly the plane lol, but I don't really want to try it out myself to confirm or debunk ;-)
 
WDD said:
My PPL CFI instilled in me to immediately raise the flaps and turn off carb heat - in that order- after touchdown in case had to take off again.

A recent flight with my CFII ( different instructor) had her comment that I shouldn’t touch anything until clear of runway. Someday might flip up the gear handle vs flaps.

I see merit in both. Thoughts?
Click to expand...

There are many things you can get hung on up, such as turning off strobes, landing lights, cowl flaps, fuel pumps, etc.. If any of them are critical to attend to right after touchdown, then go ahead and do them. Don't waste effort on lower priority items that can wait until you are clear of the runway.
 
You must log in or register to reply here.
Back
Top