A gas turbine engine, comprising: a plenum; and a coolable vane, comprising: a leading edge disposed between an inner platform and an outer platform; a trailing edge disposed between the inner platform and the outer platform; a suction side wall extending from the leading edge to the trailing edge; a pressure side wall joined to the suction side wall at the leading edge and the trailing edge and spaced from the suction side wall to form a cavity therein that includes a cooling circuit with a plurality of serpentine cooling passages; a cooling air inlet passage that is configured to receive cooling air from the plenum which is formed between the outer platform and an engine case and route the received cooling air from the plenum to the cooling circuit; and a cooling air feed elbow that includes a metering input orifice that is configured to receive compressor first discharge air and provide the received compressor first discharge air to a feed elbow cavity that is configured to redirect the received compressor first discharge air via a feed elbow output passage to a first inlet passage in the vane and to the cooling circuit; characterised in that: the vane is configured such that the cooling air received from the cooling air inlet passage and the compressor first discharge air received from the first inlet passage mix within the vane before entering the serpentine cooling passages. a plenum; and a coolable vane, comprising: a leading edge disposed between an inner platform and an outer platform; a trailing edge disposed between the inner platform and the outer platform; a suction side wall extending from the leading edge to the trailing edge; a pressure side wall joined to the suction side wall at the leading edge and the trailing edge and spaced from the suction side wall to form a cavity therein that includes a cooling circuit with a plurality of serpentine cooling passages; a cooling air inlet passage that is configured to receive cooling air from the plenum which is formed between the outer platform and an engine case and route the received cooling air from the plenum to the cooling circuit; and a cooling air feed elbow that includes a metering input orifice that is configured to receive compressor first discharge air and provide the received compressor first discharge air to a feed elbow cavity that is configured to redirect the received compressor first discharge air via a feed elbow output passage to a first inlet passage in the vane and to the cooling circuit; characterised in that: the vane is configured such that the cooling air received from the cooling air inlet passage and the compressor first discharge air received from the first inlet passage mix within the vane before entering the serpentine cooling passages. a leading edge disposed between an inner platform and an outer platform; a trailing edge disposed between the inner platform and the outer platform; a suction side wall extending from the leading edge to the trailing edge; a pressure side wall joined to the suction side wall at the leading edge and the trailing edge and spaced from the suction side wall to form a cavity therein that includes a cooling circuit with a plurality of serpentine cooling passages; a cooling air inlet passage that is configured to receive cooling air from the plenum which is formed between the outer platform and an engine case and route the received cooling air from the plenum to the cooling circuit; and a cooling air feed elbow that includes a metering input orifice that is configured to receive compressor first discharge air and provide the received compressor first discharge air to a feed elbow cavity that is configured to redirect the received compressor first discharge air via a feed elbow output passage to a first inlet passage in the vane and to the cooling circuit;