Definition
Small fairings on the underside of the wing's leading edge that cover the openings through which the slat tracks extend and retract. They close flush with the wing surface when the slats are stowed and move with the slats to maintain an aerodynamically clean leading edge.
Plain English
Little panels under the front edge of the wing that hide the rails the leading-edge slats slide on. They keep the underside of the wing smooth so air flows cleanly over it.
Context Anchor
Seen in a Configuration Deviation List when checking whether an airplane may be flown with one or more of these doors missing, damaged, or not working normally.
Derivation
A 'slat' is a thin, flat strip — here, the movable surface on the wing's leading edge. A 'track' is the rail it slides along. The 'doors' simply cover the slot where that track passes through the wing.
Why Pilots Care
Missing or damaged doors can increase drag and may be listed as an allowable CDL item only after inspection confirms no performance penalty.
Intuition Check
Do not think of these as doors for people or baggage. In this context, “doors” means small aircraft skin panels that cover or smooth an opening around the slat mechanism.
Example Sentence 1
During the walk-around, the captain checked that all slat track doors were in place and flush with the wing's lower surface.
Example Sentence 2
The CDL allowed dispatch with one slat track door removed after the required inspection verified no aerodynamic impact.