The assembly stand comprises two parallel posts (1), a horizontal girder (6) which connects the tops of the posts and is vertically movable, and a suspension frame (17) which can be displaced along the movable girder in a lateral direction and is further suitable for turning the engine (M) mounted thereon about the main axes. A lifting block (10) is provided with a lifted load sensor to record the total weight of the engine (M). The device advantageously comprises a trajectory calculating control system integrating the structural deformations caused by the lifted weight, in order to correct the docking trajectories of the modules and ensure their utmost precision.