If you look at the "main" outboard flap, there is a smaller extension on the trailing edge that seems to extend before the main flap extends. At take off, it appears that it is primarily this 'mini' flap that is extended, while the "main" flap also extends at higher settings-
Here's a picture in case I'm not explaining well- It is the final "segment" of this flap that is extended in this picture.
Photo © Martin Bauer
I'm interested in the name, and the purpose- Why not a single flap that simply extends farther down? It doesn't appear to act as a split flap.
Thanks in advance!