A casting system for forming an airfoil portion of a turbine engine component is provided. The casting system includes a main body core for forming at least one internal cavity in the airfoil portion, a microcircuit skin core for forming a cooling microcircuit embedded in a wall of the airfoil portion, and a trailing edge core for forming a cooling passage in a trailing edge of the airfoil portion. The microcircuit skin core has at least one cut-back portion which is sized so as to provide said cooling microcircuit embedded in the wall with a length which allows heat-up of the trailing edge core from a gas path.