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related questions:

My question focus on passengers jets (goes from Embraer E-jet family to Airbus A380). I don't know why pilots would attempt to takeoff without flaps but lets say they will.

Considering all the other parameters are good enough (no crosswind, long runway, aircraft light enough,...) and the pilots are aware of this unusual takeoff configuration and adapt their action accordingly (including increasing $V_r$ and $V_2$), is it possible for any passenger jet to takeoff and stay airborn (not like the flight spanair 5022) without extending flaps?

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    $\begingroup$ As for why it could be because the flaps are inoperative and no facilities for repair exist. $\endgroup$
    – ratchet freak
    Oct 17, 2014 at 10:20
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    $\begingroup$ An important aspect to this questions is not whether or not it is possible, but whether or not it is legal, with manufacturer approved procedures and performance data. $\endgroup$
    – Lnafziger
    Oct 17, 2014 at 16:12
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    $\begingroup$ @Lnafziger Indeed, but my question do not adress the reasons of such takeoff, only its possibility (I think the reasons require another question) $\endgroup$
    – Manu H
    Oct 17, 2014 at 16:35
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    $\begingroup$ Also, one other aspect you may wish to consider in this question is whether or not it is possible without slats as well, since they are generally used together and for the same reasons. $\endgroup$
    – Lnafziger
    Oct 17, 2014 at 17:08
  • $\begingroup$ This is an opinion-based question, except for a test pilot who might in a position to make no-flap departure in transport class aircraft $\endgroup$
    – rbp
    Oct 17, 2014 at 20:41

7 Answers 7

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Yes take-off without flaps is possible. The Airbus A300 and Boeing 767 are approved for such take-offs and it is being done regularly. It results in a better climb gradient, especially with one engine out. The one engine out climb gradient is an important and sometimes limiting factor in take-off calculations.

One important constraint is the length of the runway.

Another limitation, perhaps less obvious, is the maximum rolling speed of the wheels. The tires are rated to a limited speed which may be exceeded by a flap-less take-off.

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    $\begingroup$ Are you sure the 767 is "no flaps" as opposed to "flaps 1"? Flaps 1 moves the SLATS to the mid position, but no adds no flaps. Flaps 5, 15, 20 add flaps as described. Flaps 25 and 30 move the slats to the second position, and the flaps as described. $\endgroup$
    – rbp
    Oct 17, 2014 at 20:37
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    $\begingroup$ @rbp "no flaps" as in "adds no flaps". Slats are required IIRC. $\endgroup$
    – DeltaLima ♦
    Oct 17, 2014 at 20:53
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Thanks to DeltaLima for the Answer, I want to add the Fokker 100 to the Planes with no-flaps take-off capabilities. But as said you need a higher take-off speed. also stated in table:enter image description here

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you can make a brick take off without flaps, if you put enough power behind it, and those jets have enough power, (as long as the runway is long enough for those particular hunks of metal)

a good question can be added on, how long of a runway does a 'xxx' need with half load, with empty load, with full load and fuel, with broken flaps.

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    $\begingroup$ And another follow-on question to that might be "How long will it take the FAA (or other applicable regulatory agency) to revoke the pilot's license after it's discovered that he or she took off with broken flaps?" $\endgroup$
    – reirab
    Oct 28, 2014 at 7:54
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Sure.

Whether the aircraft is still on the runway or already airborne when it reaches the airspeed necessary for sufficient lift without flaps is rather irrelevant.

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    $\begingroup$ Not entirely irrelevant when you consider the tire speed limitation. $\endgroup$
    – DeltaLima ♦
    Oct 17, 2014 at 11:42
  • $\begingroup$ ground effect may help if the aircraft is still on the runway $\endgroup$
    – Manu H
    Oct 17, 2014 at 14:09
  • $\begingroup$ @DeltaLima That's only relevant to whether it can be done safely and legally, not really to specifically the question of 'can it be done?' :) $\endgroup$
    – reirab
    Oct 28, 2014 at 7:56
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The Fokker 70 and Fokker 100 take off with no flaps even on short runways.

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    $\begingroup$ Whilst this might be correct, some reference (not WikiPedia) would be good. $\endgroup$
    – Simon
    Feb 19, 2017 at 9:02
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    $\begingroup$ Especially since TesterMen Tester's answer from November 2014 already discusses the Fokker 100, with data. $\endgroup$
    – user
    Aug 14, 2017 at 12:35
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Flaps are a drag device. Airlines have toyed with the idea of no flap takeoffs for a while. You simply need higher airspeed for liftoff. It is completely safe with the correct speed....usually 3-15 knots faster depending on airframe.

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  • $\begingroup$ As highlighted by a comment in another answer, you should also consider tire limitations when asking for higher speed before liftoff. $\endgroup$
    – Manu H
    Aug 16, 2020 at 18:54
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You may be able to take off but as soon as you reach a height of 40-50 feet you lose wing in ground effect and will crash unless you have reached actual free air flying speed. Assuming a completely unobstructed route ahead of the runway the plane will eventually get enough airspeed to fly normally without flaps.

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  • $\begingroup$ Ground effect isn't an off and on thing. You gradually lose the benefits of ground effect with increasing distance to the ground. It doesn't just suddenly disappear. $\endgroup$
    – user33651
    Nov 27, 2020 at 10:06
  • $\begingroup$ I think you will find that ground effect drops off exponentially with increasing height and is only 10% by the time a height of 90% of wing span is reached. The other factor is that the plane will stall very easily because of the high angle of attack normally involved in take-off and there is little height to play with to drop the nose back down. $\endgroup$
    – Bryan Duggan
    Nov 28, 2020 at 17:19

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