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Aviation glossary

Flap

Also: flaps, trailing-edge flap, high-lift device

The aircraft

Movable surface on the trailing edge of the wing that extends to increase lift at low speed during take-off and landing.

What it is

A wing optimised for fast cruising produces little lift at low speed. Flaps solve the problem: extending backwards and downwards, they increase the camber of the wing section and, often, its area, so the aircraft can take off and land at lower speeds and on shorter runways.

Pilots select them in stages: numbered positions up to FULL on Airbus types, degrees of deflection on Boeings. Take-off uses an intermediate setting, because more flap brings more lift but also more drag; landing uses a larger one, which also helps slow the aircraft on approach. Slotted flaps, with one, two or three slots, let air flow from the lower surface to the upper one to keep the airflow attached; the Boeing 727 was known for its triple-slotted flaps.

On Vuelopedia

Boeing 727

Related terms

SlatMovable leading-edge surface that moves forward to open a slot, letting the wing reach a higher angle of attack before it stalls. WingSurface that generates the lift needed for flight; on airliners it usually also holds much of the fuel and carries the engines. Take-offThe phase in which an aircraft accelerates along the runway to rotation speed, raises its nose and climbs away to a safe height above any obstacles. LandingThe final phase of flight in which the aircraft crosses the runway threshold, touches down on its main gear and slows to taxi speed. Take-off distanceDistance an aircraft needs from the start of its take-off run until it reaches a reference height above the runway, normally 35 feet for transport aircraft.
Whole glossary

Cite

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This page was last updated on October 9, 2026

APA

Vuelopedia. (2026, October 9). Flap. Retrieved October 17, 2026, from https://vuelopedia.org/en/glossary/flap

MLA

“Flap.” Vuelopedia, Fundación Poderia, 9 Oct. 2026, vuelopedia.org/en/glossary/flap. Accessed 17 Oct. 2026.

Chicago

Vuelopedia. “Flap.” Fundación Poderia. Last modified October 9, 2026. https://vuelopedia.org/en/glossary/flap.

Harvard

Vuelopedia (2026) Flap. Available at: https://vuelopedia.org/en/glossary/flap (Accessed: 17 October 2026).

BibTeX

@misc{vuelopedia_en_glossary_flap,
  author       = {{Vuelopedia}},
  title        = {{Flap}},
  publisher    = {Fundación Poderia},
  year         = {2026},
  date         = {2026-10-09},
  url          = {https://vuelopedia.org/en/glossary/flap},
  howpublished = {\url{https://vuelopedia.org/en/glossary/flap}},
  urldate      = {2026-10-17},
  note         = {Accessed 2026-10-17}
}

Wikipedia

{{cite web |url=https://vuelopedia.org/en/glossary/flap |title=Flap |website=Vuelopedia |publisher=Fundación Poderia |date=2026-10-09 |access-date=2026-10-17 |language=en}}

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