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This question is about light, tricycle, single engine aircraft.

I have made it a habit to raise the flaps right after touchdown (when the nosewheel is on the ground). My instructor used to do that every time during initial training so I took over the habit.

It makes sense to do this for the following reasons:

  • better braking performance because lift is reduced while rolling out
  • less crosswind effect, reducing the risk of loss of directional control after landing
  • (less important) it's part of the after landing checklist, so when it's done, it's done

However, I was recently checked out on a C182 that I wanted to rent in Florida and when I raised the flaps right after touchdown the instructor shouted "what the < beep > are you doing? You should never raise the flaps until you've turned off the runway". He couldn't provide a good reason though, so when I told him about the things I listed above he simple mumbled something about keeping my attention on the runway instead of fiddling with the flaps lever (which is a something I don't even have to think about)

My question is: Is it really a bad idea to raise the flaps that soon after landing? Or is it actually a good habit?

(I noticed that most airliners also wait until they're clear of the runway, but these jets have spoilers to get rid of all the lift)

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There's an old but interesting discussion about this topic here: pprune.org/flying-instructors-examiners/… –  Philippe Leybaert Jan 21 at 17:00
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I raise the flaps after I know that I am not going around and most of the aerodynamic braking is done (can't hold the nosewheel up anymore). It helps quite a bit with braking and it puts more weight on the main wheels. If you don't know what switch you're pulling when you do it you probably shouldn't be flying an airplane. Now if you're a student pilot or something and you aren't comfortable with the aircraft yet sure just wait for the after landing checklist. Seriously though I can't believe how many pilots think that they will just grab the gear switch and lift it, do you even look first? –  p1l0t Jan 21 at 22:15
    
FWIW: I was always taught to concentrate on the rollout and slowdown etc and only raise flaps once clear of the RW –  Jamiec Jan 22 at 12:59
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@p1l0t There is simply no need. If you are heads down and looking at the flap handle, then you aren't looking outside. There are things outside that can hurt you. Also, if the aerodynamic braking is done, then putting the flaps up isn't going to put much more weight on the wheels because there isn't much airflow holding it up. –  Lnafziger Jan 23 at 5:13
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Most of the time, no you really don't NEED to do it. A good landing you really shouldn't need to use the brakes at all. Still I don't understand the fear in raising the flaps on the runway. Multitasking and dividing one's attention are essential skills of a pilot and the after-landing roll-out is generally a fairly low-workload time. I just don't understand how pilots are so afraid of pulling up the gear or getting distracted. It helps tremendously with reducing ground roll in my experience. MOST of the time though, I will agree with you that there is no need to do it until you clear. –  p1l0t Jan 23 at 17:01

9 Answers 9

up vote 28 down vote accepted

You should wait until clearing the runway before performing any non-essential checklist items because you are still in a critical phase of flight and at a relatively high risk while still on the runway. You should focus 100% of your attention to controlling the airplane (don't stop flying the airplane until you come to a complete stop) and watching for other traffic (or someone crossing the runway in front of you) that might be a hazard.

There is also the possibility that in a retractable gear airplane you could accidently retract the gear if you are moving things while still preoccupied with landing. Once you exit the runway and come to a complete stop, you can devote the proper attention to the after landing checklist so will be more likely to complete it correctly without missing any items that may become an issue on your next flight.

That being said, follow the guidance in your POH. Sometimes there are abnormal situations that actually call for this, like voretaq7 mentions in his answer, the Cherokee POH references it as a short field landing technique.

FAA Guidance

The FAA also covers this in AC 91-73B - Parts 91 and 135 Single Pilot, Flight School Procedures During Taxi Operations. It says (in part):

7. SINGLE-PILOT PROCEDURES.

a. General.

...

In addition, upon landing, no items should be changed or moved until the entire aircraft has crossed the respective runway’s hold short line.

...

NOTE: After the entire aircraft crosses over the landing runway’s hold short line, conduct after-landing checklist items, based upon company procedures, before contacting ATC for taxi instructions.

You could also fail a checkride for doing this

The PTS also repeatedly stresses the objective:

  • Utilizes after landing runway incursion avoidance procedures.

To figure out what they mean by that, we can look at their Runway Incursion Avoidance material, which says:

Finally, after landing and upon exiting the runway, ensure your aircraft has completely crossed over the runway hold markings. Once all parts of the aircraft have crossed the runway holding position markings, you must hold unless further instructions have been issued by ATC. Do not initiate non-essential communications or actions until the aircraft has stopped and the brakes set.

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The retractable landing gear is an excellent point. It makes perfect sense. I've read a few stories of pilots retracting the gear after landing instead of raising the flaps. –  Philippe Leybaert Jan 20 at 23:00
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(Unless you're Bob Hoover, who routinely retracted the gear while still on the runway, but as they say about him: planes were simply afraid of not doing what Bob Hoover intended) –  Philippe Leybaert Jan 20 at 23:00
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The retractable landing gear issue is particularly notable because early in the landing roll you may not have enough weight on the wheels to activate the squat switch that prevents you from retracting your gear while you're using them to hold the plane up. Your perfect landing could turn into a nice, smooth gear-up incident if you bump the wrong switch. –  voretaq7 Jan 20 at 23:02
    
Would it also make sense to have the flaps down just incase you have to lift off again for any reason? Though maybe I'm being silly and thinking about aircraft carriers. –  Jay Carr Jan 24 at 17:45
    
@JayCarr Well, in the event of a go-around, you will usually need to change the flaps to the takeoff setting either way. –  Lnafziger Jan 24 at 19:08

Raise the flaps after leaving the runway.

Consider:

  • A light single doesn't weigh that much and in the short time slowing down from the speed you touchdown at and taxi speed, the difference in weight on wheels between flaps 0 and flaps X is not worth worrying about unless you are landing on a true short field.
  • If the crosswind is that strong, you still need to apply proper control deflection with the flaps up. Don't let complacency bite you on this one.
  • The after landing checklist is called for after exiting the runway, not while on the runway.

And the biggest reason:

  • You will fly something bigger and/or complex one day (maybe) and there will be more than a simple flap lever to touch and it is best to wait to mess with those controls until things have settled down and you are taxiing.

That instructor got on your case, I know examiners that will take exception to touching the flaps on the runway and I can say for certain any OE Captain or APD will really get on your case for doing it. Start proper habits now, particularly if you aspire to fly anything bigger than a light single.

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and you may need to do a touch-and-go, no flaps means you just power of the end of the runway –  ratchet freak Jan 21 at 8:40
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@ratchetfreak: well not necessarily, but certainly when you get to something more complex, which is why some advocate following similar procedures in small aircraft to "get used to it". Even thinking of attempting a go-around in something like a MU2 without flaps makes me shudder... –  Qantas 94 Heavy Jan 21 at 9:40
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@ratchetfreak it is true you may need to raise the flaps (or set them to a specific setting) for a touch and go, but I'll argue that you can't use that exception to justify always raising the flaps on the runway. –  casey Jan 21 at 14:20

Raising the flaps right after touchdown. Good or Bad? -- The answer is an emphatic Yes.

The major reason for not raising your flaps until you've cleared the runway and come to a stop is that it's one more thing for the pilot to do in an already workload-intensive period (landing). As others have pointed out you might hit the wrong control or otherwise mess up in a way that can ruin your day.

As a matter of general procedure I was taught not to raise the flaps until clear of the runway for normal landings, and that's what I do. It seems the safest way to operate since there's always plenty of time to do things after you've cleared the runway and stopped.


The major reason for raising the flaps while you're still on the runway is, as you pointed out in your question, better braking performance - I don't know about for the Cessna 182, but it's mentioned as part of the short field procedures in the Cherokee POH: There will be less chance of skidding the tires if the flaps are retracted before applying the brakes.
They're not saying "retract the flaps", but they're certainly waggling their eyebrows suggestively while pointing at the flap lever and mouthing "save your tires".

Empirically (yeah, I tested it, I'm strange like that) retracting the flaps on the Cherokee makes a small but appreciable difference in stopping distance (and a noticeable difference in how hard I can hit the brakes before the tires protest), so when I'm landing on an actual short field or drilling short-field procedures I retract the flaps during rollout at about the same point I would in a touch-and-go landing.

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Yes good or bad? –  Philippe Leybaert Jan 20 at 23:41
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It's contextual. If you're doing a legit short field landing and you need better braking, perhaps you should retract your flaps prior to coming to a complete stop (provided you have the directional control). If you're executing a normal landing... just don't do it. I'd consider it an abnormal procedure, honestly. –  egid Jan 20 at 23:58
    
@PhilippeLeybaert It can be good, or it can be bad - it depends on the situation. As a general rule absent a good reason (like executing an actual short-field landing) it's not "normal procedure". –  voretaq7 Jan 21 at 0:45

I say bad for some planes. Also other planes it will be bad in some conditions. So follow what the operations manual says for that plane.

Using full flaps is a very high drag and very poor L/D ratio configuration for the plane to be in. By raising flaps the potential increase in tire grip (from reduced lift) for braking is offset partially or entirely by the reduction in aerodynamic drag. There will be a speed threshold somewhere that will mean fully retracted flaps provides more braking than full flaps, but don't forget you have to transition from fully extended to retracted giving you a surge in your L/D ratio. Remember that takeoff flaps setting gives better L/D ratio than no flaps at that speed and AoA.

All of those things changing during landing does not lend itself to smooth, predictable, and easier controlled deceleration. Plus, as others have pointed out, retracting your flaps partway through a landing distracts you from your task at hand, and for limited or no benefit or even, worse braking performance.

Edit: The better braking performance with flaps up may be true for some planes but not for all "light" tricycle single engine aircraft. This will depend on many design factors that the operation manual authors choose to use the KISS principal and just say always continue the rollout with the full flaps until you're off the runway or parked.

During rollout the wings may transition from flying to fully stalled due to the reduced air speed while on full flaps. This will be a sever reduction in lift, that greatly enhances tire grip, while at the same time has all of the drag as before. If the flaps are retracted in this sort of plane at that stage the wings may go back to flying while at the same time reducing the amount of drag (giving the surge in L/D). This surge will be particularly bad during the transition from full to no flaps. Even though there will not be enough lift to make any wheels come up, it will reduce the tire grip. That reduction in grip could cause one of the rear wheels to skid, suddenly reducing the braking performance of one side of the aircraft and cause the plane to spin around. Depending on the speed you're going when your nose gear touches down and you decide to retract the flaps, this could be very bad. Even if that extreme doesn't happen, the the loss of tire grip at the same time as a reduction in drag from the flaps means less braking performance.

In the planes the OP flies their wings may remain flying (not stalled) for the "high" speed part of the rollout that aerodynamic forces are significant, so retracting the flaps severely reduces the lift and a bit of drag, giving the tires much more grip and braking power than any loss of aerodynamic braking provided by the flaps.

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The transition phase is a good point. It's similar to the (often terrible) idea of raising gear on a twin during a takeoff engine failure. The massive increase in interference drag can be far worse than the gear down drag on its own. –  egid Jan 21 at 4:55
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I have experienced a very noticeable effect on braking performance when raising the flaps. The drag caused by full flaps is nowhere near as effective as the improved braking made possible by retracting the flaps. –  Philippe Leybaert Jan 21 at 17:55
    
How could a surge in L/D ratio cause a problem on rollout? Drag and lift will both be reduced and although drag will be reduced more, the landing speed of light single is too slow for that to have a noticeable effect. –  Philippe Leybaert Jan 21 at 19:21
    
How can a wing become stalled due to reduced airspeed on rollout? The AOA doesn't change at all. –  Philippe Leybaert Jan 25 at 0:16
    
I know the AoA doesn't change but the Reynolds Number does reduce with air speed, which changes the AoA that stall happens at. Also retracting the flaps will also shorten the chord of the wing in some planes which also reduces the Reynolds number. –  BeowulfNode42 Jan 25 at 0:27

I say raise the flaps (for the advantages that you enunciated), as long as you first make sure that:

  • You won't be going-around
  • You have little chances of hitting another control by mistake
  • The aircraft is stable and you've taken care of other essential concerns

That would probably not be directly after touchdown, but maybe a little later. So basically, make an informed action depending on the aircraft and the situation.

Thanks to all those who answered. Lots of interesting and useful information here.

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You say that you don't even think about 'flipping the lever'. Well, that means that you missed something very basic in flying habits. Raising the flaps means - moving that relevant lever AND making sure that they are up - either visually or by indicator. This you should not be doing while taxiing and definitely not ON the runway. Just like when you take of you apply full power - which means - you push the throttle all the way in AND check you have max RPM and all you engine gauges are green.

My answer is a definite - No.

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Somehow I don't like the tone of this answer. –  Philippe Leybaert Jan 21 at 17:41
    
nothing wrong with the tone. ... or the ESSENCE of it. –  vector Jun 18 at 19:50

This may be a dead thread, but I wanted to interject something my CFI taught me. He also instructed me to raise flaps right after touch-down in a 172, his reason being this:

In a high wing plane, full flaps divert air flow from the empennage and elevator. If you have the elevator deflected all the way up (yoke back), it creates much more drag then full flaps because of the way the air travels around the plane. If you have flaps down, your are getting some aerodynamic braking, but not nearly as much as you would if you clean up the flaps and hold the yoke back.

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Raising the flaps while still on the runway is definitely grounds for getting at least a 'talking to' by the examiner :-( No pink slip but bad aftertaste especially when the checkride is in the bag otherwise.

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Just throwing this in as an answer since nobody mentioned it.

In a light aircraft on a large runway I usually raise the flaps right after touchdown if I actually want to roll FASTER in order to expedite vacating the runway.

Most of the runways where I'm landing have >4 times the LDA that I need, so I'm usually aiming for a quick touchdown before the exit intersection and a quick exit. If I touchdown way before my exit, then raising flaps and letting the a/c continue on the r/w at a fast pace is gladly appreciated by the 737 behind me on short final.

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