Abstract: Disclosed is a removable device for the supporting of equipment in an aircraft, especially to fasten the support of a head-up collimator with its projection system, above the seat of the pilot of the aircraft. To enable the support to be dismounted (for maintenance for example), and to be put back in place at its exact position, the fastening device is made as follows: it is hinged on the aircraft by a hinge and it is fastened by bolts enabling the fastening of the support according to an angle that is variable about a rotation axis. The device furthermore comprises a centering block that cooperates with a centering pawl, one of the two elements being part of the aircraft while the other is part of the support, the pawl being housed in a removable way in a positioning aperture formed in the centering block, the block comprising a cup filled with resin, the resin being used to define and maintain the position of the aperture with respect to the cup.