The invention relates to a covering cap assembly (1) for a transverse girder (2) of a roof luggage rack designed so that a profiled forward end of the girder can be covered and locked. According to the invention the assembly is held together by a hinge (6) and consists of a covering cap (3) with a lock (4) and a bearing element (5). The bearing element (5) is inserted into a longitudinal slot at the underside (14) of the transverse girder (2) and is positioned and held in place interlockingly in the transverse profile. Retention in the longitudinal slot is provided by a locking element (21) and a rivet (24). In this way a simple construction of a cover cap assembly is had that is inexpensive in manufacture and assembly and is reliable in its functions and easy to handle.