the cooling air flow through the trailing edge region of airfoil 10 the arrows 48 depict the path taken by the cooling air as it enters the cooling air input channel 26 formed in the suction side wall 12 flows through the narrow passageway 34 also formed in suction side wall 12 takes a ninety degree turn to enter cooling air output channel 40 formed in the pressure side wall 14 takes another ninety degree turn within output channel 40 and exits through the cooling air discharge slot 44 on the pressure side wall 14 of airfoil 10 as previously mentioned the scrubbing action provided by the cooling air as it follows this tortuous crossover path through the trailing edge region 22 maximizes the filling of the discharge slots 44 and improves the cooling of the trailing edge region 22 it has been previously mentioned that the airfoil 10 can be cast as a single piece or formed of bonded pieces if it is formed of a single piece the cooling air input channel 26 and passageway 34 in the suction side wall 12 would be formed by the core of the casting and the cooling air output channels 40 would be machined later if the airfoil is formed of two or more pieces the channel configurations would be machined in both surfaces before they are bonded together in addition.