
1) Aircraft control
Found on
https://www.crosswordclues.com/clue/fowler-flap

Trademark name of a split-flap attached to a wing's trailing edge with a system of tracks and rollers to roll the FLAP backward and downward, increasing the wing area. Named for its inventor, USAAF engineer Harland D Fowler.
Found on
http://www.aerofiles.com/glossary.html

Trademark name of a flap attached to a wing's trailing edge with a system of tracks and rollers to slide backwards before hinging downwards, thereby increasing both camber and chord, creating a larger wing surface better tuned for lower speeds. Named for its inventor, USAF engineer Harland D Fowler.
Found on
https://www.encyclo.co.uk/local/22323

a flap normally forming a part of the trailing edge of an airplane wing, capable of being moved backward and rotated downward in order to increase lift through increased camber and wing area.
Found on
https://www.infoplease.com/dictionary/fowler-flap
No exact match found.