The leading edge slat tracks go through holes in the front spar. Track cans are attached to the front spar and isolate the tracks from the wing fuel tanks. Liquid from the slat tracks collects in the cans and then flows down drain-pipes to drain holes in the bottom skin.
A320Ceo At track 4 in both wings there is a dry bay and no cans.
Liquid from these tracks falls to the bottom skin and then flows out from the dry bay drain – holes
A320Neo Track 4 has its can and its drain hole
Author – Zinhom Mohmoud – Aviation Training Consultant