The Function of Black Triangles Inside Airplanes
Have you ever noticed this when boarding a plane? If you let your eyes wander around the cabin on the way to your seat, you’ll notice small, black triangles above some of the windows on the left and right sides of the plane.
Some types of commercial aircraft have such triangles, usually four. One on each side at the height of the leading and trailing edges of the wings. They mark the two points from which the crew has the best view of the wings during visual inspection. This means that they do not have to look for a suitable window in the cabin,” explains the Lufthansa Technik spokesman.
And this can be crucial, especially when time is short in an emergency situation.
For example, if a visual inspection of the flaps is required, the window under the forward markings provides the best view of the flaps on the leading edge of the wing, the so-called slats. The window under the rear marking provides the best view of the trailing edge of the wing, where the flaps are located.