Have you ever paid attention to how the wings of air liners deform during the flight? Metal panels are raised, the angle of inclination of which periodically changes. What happens to the aircraft and why these manipulations are needed, the pilot tells on his Aviator channel. The panels on the wings are called spoilers, they are designed to slow down the aircraft. The need to reduce speed or altitude often occurs during flight, before landing this is standard procedure. Simply reducing the intensity of the engines is not enough; the aircraft is inert at high altitude, and its maneuverability is not very great. Therefore, additional methods of braking are required. As the spoilers rise, the air resistance area of the wing increases and the speed of the liner decreases. By changing the angle of the panels, you can also adjust the direction of the aircraft. They are never fully raised – with a critical drop in airspeed, the liner will simply fall. 
When descending, the plane accelerates, spoilers are also needed to control it. They play a particularly important role during landing, when the speed must be reduced as quickly as possible. The panels are fully raised, increasing the resistance of the wing to the limit, which ensures a stop in a short time.
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