A gas turbine engine hollow turbine airfoil having pressure and suction sidewalls extending chordwise between leading and the trailing edges. The trailing edge includes a pressure sidewall lip and a suction sidewall lip, and a breakout distance between the pressure sidewall lip and the suction sidewall lip. A cooling fluid channel extends spanwise through the airfoil for supplying a cooling fluid to the airfoil. Flow channels are provided extending chordwise between the cooling fluid channel and the suction sidewall lip and include a metering section, an internal diffusion section and a breakout slot. The interior diffusion section includes a spanwise dimension and a widthwise dimension perpendicular to the spanwise dimension, wherein the spanwise dimension continuously increases extending in the chordwise direction, and the widthwise dimension continuously decreases extending in the chordwise direction.