Gate 41Things that look scary but have an explanation
Why does the wing seem to come apart?
Pieces of the wing are sliding out. Is that supposed to happen?
Flaps (trailing edge) and slats (leading edge) are high-lift devices. They change the wing's shape and area, so it can make enough lift at the slow speeds of takeoff and landing. They are tucked away for cruise because they add drag.
They run on tracks driven by motors and are selected with a lever in the cockpit in set steps (for example "Flaps 1, 2, 3, Full"). The gaps you see are designed slots: they let air flow smoothly over the top surface.
More flap means a lower landing speed and a shorter landing run. The crew choose the setting from weight, wind, runway and the aircraft's manuals.
A little deeper
Slots let high-pressure air from beneath the wing energise the thin layer of air on top (the boundary layer), so the wing can fly at a higher angle before it stalls.
Fowler flaps slide backward as well as rotating down, which increases wing area as well as curvature.
You may see flaps move while taxiing: crews set takeoff flaps early, and they also run a flight-controls check before takeoff.
See it in Gate 41, in the outside view
Related questions
People involved
- First Officer Mateo AlvarezFirst officer (co-pilot)
- Kenji WatanabeAircraft maintenance engineer