Abstract: Intersecting judiciously located installed holes at the tip section of the airfoil of an internally cooled axial flow turbine blade for a gas turbine engine communicating with a passage adjacent the pressure side and another passage adjacent the suction side of the airfoil provide a resultant flow that creates an aerodynamic seal that opposes the flow of engine working medium leaking into the clearance between the tip of the airfoil and the surrounding annular shroud or outer air seal. The installed holes are in proximity to the intersection of the tip surface with the airfoil pressure side surface.