A stepped-designed beam arm wiper assembly has a beam arm that locks into a mounting head such that the beam arm can be disconnected from the mounting head for servicing a wiper blade attached to the beam arm. A head cover is attached to the mounting head via hinges on either side of the head cover which allow the head cover to open off the head on either pin hinges of the head, and can be pressed onto the head and retained on. The other end of the beam arm is inserted into an adapter which snaps onto a rear wiper blade coupler via lead-in hole and trunnion connection. The beam arm has an airfoil with a stepped design to match the head cover, adapter, and blade assembly stepped design.