Take the 2-minute tour ×
Aviation Stack Exchange is a question and answer site for aircraft pilots, mechanics, and enthusiasts. It's 100% free, no registration required.

I have heard pilots talk about flaps and slats, seemingly interchangeably.

Is there a difference between a flap and a slat or they are the same thing?

share|improve this question

2 Answers 2

up vote 19 down vote accepted

Flaps are at the back of the wing, slats are at the front.


Easy! :)

If you want it more technical: They both help to generate more lift. See these diagrams with angle of attack and lift coefficient:



As the lift coefficient is inversely proportional to the minimum airspeed, a higher CL will allow a lower Vmin.

share|improve this answer
Both the lectures that I know and almost all sources on the internet describe a reduced stall AoA with flaps, i.e. a c_L / alpha curve that is moved both up and towards the left. This is important, because it means that an extension of the flaps alone can cause a stall without changing the AoA. Forum post with good sources: forums.x-plane.org/?showtopic=59032 –  JulianHzg Mar 18 at 9:50

Slats and flaps both change the shape of the wing when they are extended and allow the wing to generate more lift so that the airplane can fly slower.

Operationally they are both retracted and flush against the wing except for takeoff and landing at which time they are extended.

Pilots tend to refer to them together because they are used for the same purpose and used at the same time. In fact, they are normally even moved by using the same control (typically the slats comes out when selecting first detent, and then the flaps come out progressively further at each detent):

Airbus Slat/Flap Handle

Slats are on the front of the wing (on the left in this picture) and the flaps on on the back of the wing (on the right). As you can see, they both tend to make the wing bigger and more curved when they are extended:

Aircraft Wing

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.