An airfoil for a gas turbine engine, wherein the gas turbine engine defines a longitudinal axis, the airfoil comprising: a body defining a tip flag configured to conduct cooling air through the body, wherein the tip flag terminates at a tip flag terminus axially forward of a trailing edge of the airfoil; wherein the body further defines a serpentine channel and a trailing edge channel, each configured to conduct cooling air through the airfoil with the serpentine channel terminating at a serpentine channel terminus and the trailing edge channel terminating at a trailing edge channel terminus; and wherein the tip flag terminus is axially forward of the serpentine channel terminus and the serpentine channel terminus is axially forward of the trailing edge channel terminus wherein the tip flag comprises: a tip flag leading edge channel disposed along a leading edge of the airfoil, a longitudinal tip channel extending axially aftward along a radially outermost surface of the airfoil and terminating at the tip flag terminus, and a first tip flag channel turn comprising an about 90-degree bend proximate to a corner of the leading edge of the airfoil and the radially outermost surface of the airfoil connecting the tip flag leading edge channel to the longitudinal tip channel; the body further defining a tip channel core tie disposed in the longitudinal tip channel and defining a through hole in the radially outermost surface of the airfoil; and characterised in that the body further defines a leading edge corner core tie disposed in the first tip flag channel turn and defining a through hole in the radially outermost surface of the airfoil. a body defining a tip flag configured to conduct cooling air through the body, wherein the tip flag terminates at a tip flag terminus axially forward of a trailing edge of the airfoil; wherein the body further defines a serpentine channel and a trailing edge channel, each configured to conduct cooling air through the airfoil with the serpentine channel terminating at a serpentine channel terminus and the trailing edge channel terminating at a trailing edge channel terminus; and wherein the tip flag terminus is axially forward of the serpentine channel terminus and the serpentine channel terminus is axially forward of the trailing edge channel terminus wherein the tip flag comprises: a tip flag leading edge channel disposed along a leading edge of the airfoil, a longitudinal tip channel extending axially aftward along a radially outermost surface of the airfoil and terminating at the tip flag terminus, and a first tip flag channel turn comprising an about 90-degree bend proximate to a corner of the leading edge of the airfoil and the radially outermost surface of the airfoil connecting the tip flag leading edge channel to the longitudinal tip channel; the body further defining a tip channel core tie disposed in the longitudinal tip channel and defining a through hole in the radially outermost surface of the airfoil; and characterised in that the body further defines a leading edge corner core tie disposed in the first tip flag channel turn and defining a through hole in the radially outermost surface of the airfoil. a tip flag leading edge channel disposed along a leading edge of the airfoil, a longitudinal tip channel extending axially aftward along a radially outermost surface of the airfoil and terminating at the tip flag terminus, and a first tip flag channel turn comprising an about 90-degree bend proximate to a corner of the leading edge of the airfoil and the radially outermost surface of the airfoil connecting the tip flag leading edge channel to the longitudinal tip channel; the body further defining a tip channel core tie disposed in the longitudinal tip channel and defining a through hole in the radially outermost surface of the airfoil; and characterised in that the body further defines a leading edge corner core tie disposed in the first tip flag channel turn and defining a through hole in the radially outermost surface of the airfoil.