Flaperons - A (not so) quick explanation

With all the talk surrounding flaperons, I thought it might be a good idea to write something in RWA to explain why they’re there and how they work IRL.

flaperons do quite literally what it says on the box, they’re both flaps and ailerons.

During takeoff and landing, they’ll behave like flaps and droop with the flaps. Their party trick is that they can still move up and down really quickly while drooped, unlike flaps and like an aileron. This allows the pilots to have more control over the roll of the aircraft while also not sacrificing on lift capability because the upward deflection of one flaperon is equal to the downwards deflection of the other flaperon.

In cruise, those flaperons act like normal ailerons.

During rollout after landing, those flaperons go to full upwards deflection to decrease the amount of lift generated on the wings.

Here are some images showing them in action and to illustrate what I’m talking about. (All of the photos belong to me)

  1. No control input - Flaperon flush with the flaps, aileron in neutral position.
  2. Control input to the left - Flaps raise slighty while the flaperon deflects slightly downwards compared from last image to produce left roll in tandem with the outboard aileron deflecting downwards.
  3. Roll complete, no control input - Flaps now up. flaperon fully up with flaps, aileron in a neutral position.
  4. Rollout after landing - Flaperon fully up to decrease lift after landing.

If you’re confused about anything. I apologize, it’s a little late and some things might need further explanation, feel free to ask below.

I still don’t know what you trying to tell …

Hey @Danman
Nice pictures! I can identify four devices:

  • the inboard aileron
  • the flap
  • the outboard aileron
  • the flight spoilers

My analysis:
Picture 1: right turn climb with flaps 1 notch deflected. Ailerons neutral.
Picture 2: lifting the right wing while climbing. Outb. and inb. aileron are slightly down deflected. Flap 1 notch deflected,
Picture 3: the wing is clean, cruising configuration.
Picture 4: flight spoilers and flaps are extended for touchdown and braking.

I don’t see flaperons. The only flaperons I have seen so far were on a A330, where during the landing both outboard ailerons were down deflected to increase lift in combination with the flaps and simultaneously moving in opposite directions to control the roll as normal ailerons.

Happy landings


I think this is a 777 wing?

If so what you have described as the inboard aileron @Laminar is actually the flaperon I think. See the diagram below:

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Thank you @ATK. It looks like it could be a flaperon, but in this case it should be deflected in combination with the flaps, in the picture 4.
Instead it is neutral, like the aileron…for this reason I believe is just a inboard aileron.

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I am afraid you are wrong. Whilst the 777 flaperons generally droop with the flaps, on the runway when the spoilers deploy they are in line with the wing in the non-drooped position. They then droop again when the spoilers are retracted. This is partly to reduce lift.

Have a look at this video to see the 777 flaperon in action, and note how it stays up after the speedbrakes deploy buts droops after the speedbrakes are retracted.


Nicely done. Great job on the explanation

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Hey @ATK @Danman
You are right. It is a flaperon on a B777. It was probably down with the flaps during the approach and lifted up just before the picture 4 was taken.
You earned a cookie👏🍩

Blue skies:)


It is a 777 wing, the mechanisms work the same way on the 767, 777, and the 787. It applies to all aircraft equipped with flaperons.


Wait, so what’s the difference between flaperons, ailerons, and spoilerons? I’m still kind of confused.

Flaperons are surfaces that act as both flaps and ailerons. Ailerons control the rolling motion of the aircraft. Spoilerons are just spoilers that can move to help with the rolling motions of the aircraft.

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