PURPOSE: To utilize a cockpit as a well even at use for a seat, by protrusively providing a hatch coaming for the well in the cockpit, arranging a plurality of its openings simultaneously forming their hatch cover in an open-closable state separately from each other.

CONSTITUTION: In a cockpit a hatch coaming 5 of a well 4 is protrusively provided simultaneously to said coaming a plurality of openings are arranged, then a plurality of hatch covers 7, 7 corresponding to these openings are mounted in an open-close capable state independently to each other thus the well 4 can be utilized also when the hatch coaming 5 is in use for a seat part.