Flaps are movable panels located on the trailing edge of the wing that increase lift, camber and effective wing area, allowing lower landing speed. Spoilers are panels along the upper surface of each wing that reduce lift and add drag. They are designed to increase drag, help slow the aircraft down and lose altitude. Spoilers are used just forward of the flaps, moving only upward, while flaps move along built-in tracks during takeoff and landing.
Expert behind this article
Jim Goodrich
Jim Goodrich is a pilot, aviation expert and founder of Tsunami Air.
What is the difference between airplane flaps and spoilers?
The difference between airplane flaps and spoilers is that flaps increase lift for take-off and landing, while spoilers cancel lift and add drag to slow the aircraft. Flaps extend rearward and downward from the trailing edge, increasing camber and wing area so that lift rises at low speed. This extra camber also increases drag. Spoilers are hinged panels that only move upward. Once lifted, they spoil part of the lift and add drag. Because spoilers differ from airbrakes, they both increase drag and disrupt lift distribution, whereas airbrakes increase drag without disrupting lift. After touchdown, landing spoilers are fully deployed immediately so that lift drops and weight transfers to the wheels.
Where are flaps and spoilers located on an aircraft?
Flaps are hinged panels located on the trailing edge of each wing and usually extend from the wing root to just inboard of the ailerons. They ride on metal tracks built into the wings so they can extend rearward and downward when the crew selects extra lift or drag.
Spoilers are large panels that sit on the upper surface of each wing, positioned close to the wing root. When deployed, they project into the airflow above the wing, reducing lift and adding drag.
Which creates more lift: flaps or spoilers?
Flaps create more lift than spoilers. Spoilers lift the flaps upward, destroying the wing's camber, so the wing creates less lift. Spoilers never create lift but only cancel it.
When are flaps used compared to spoilers on an aircraft?
Flaps are used during takeoff at a moderate setting to give high lift with low drag. Spoilers are used during the final approach to touchdown. At touchdown, and throughout the landing ground roll to shed energy, they are deployed automatically upon landing and are used after a rejected takeoff.
How are flaps controlled compared to spoilers?
A pilot moves a lever or twists a wheel to command the flaps through mechanical cables and jackscrews. Spoilers are steered by an electronic control system that signals hydraulic actuators on every panel. Flap settings are thus locked in detents, but the same system that runs the spoilers also lets the flight crew touch a switch and deploy them manually. Because each spoiler surface is hinged and small, hinged aircraft spoilers are much more easily controlled, allowing split-second, asymmetric corrections that the slower, synchronous flaps cannot match.
What are the advantages and disadvantages of flaps?
Advantages of flaps are that they help increase the camber of the airplane wing, and they add surface area to the wing. These changes let the wing change shape in flight so that the airplane can fly more slowly without stalling. Lower stall speed, in turn, allows pilots to approach runways more slowly and to land within shorter distances. Flaps permit steeper descent angles without airspeed increase, so aircraft can lose altitude quickly while staying at a safe speed.
Flap extension permits lower landing speed, reduces landing roll length, and allows steep controllable angle during landing. Full flaps allow slower approach speeds and steeper approach angles. Fowler flaps increase the area of the wing by extending out on rails or tracks, giving even more lift and drag. The large aft-projected area of the flap increases drag, which helps slow the aircraft.
Disadvantages of flaps are that they accentuate the tendency for airplanes to weathervane into the wind, making cross-wind landings trickier. Flap extension results in nose-down force that pilots must trim out. The same surface area that gives slow-flight lift also adds weight and complexity to the wing. Thus, pilots optimize them for each phase, using only as much flap as the runway and wind demand.
Expanding the control surface raises the wing's surface region, giving the pilot better adaptability. I recognize this because it permits the aircraft to advance for touchdown at a high viewpoint.
Jim GoodrichPilot, Airplane Broker and Founder of Tsunami Air
What advantage do spoilers give an airplane?
Spoilers give pilots a way to precisely control lift and drag at different phases of flight. They help slow the aircraft down, manage airspeed without relying solely on engine power changes, and increase descent rate without increasing speed. By disturbing smooth airflow over the wing, spoiler panels produce aerodynamic drag and increase form drag, creating a braking effect. This allows pilots to descend more quickly without overspeeding and to control altitude and speed precisely. Spoilers are used to control rate of descent for accurate landings and help control landing performance.
On touchdown, spoilers fully deploy to put the full aircraft's weight on the wheels, maximizing wheel brake efficiency and helping reduce ground roll after landing. Ground spoilers force the full weight of the aircraft onto the landing gear, making brakes work more efficiently. Spoilers prevent aircraft from bouncing upon landing and help keep the plane on the ground. They can be used as speedbrakes during final approach and after landing. Spoilers supplement or replace ailerons for roll control, eliminating adverse yaw and reducing the twisting force that ailerons can create at high speeds.
