A method of manufacturing a gas turbine engine, the method including providing a fan having a plurality of fan blades circumscribed by a fan track liner and attaching a cutter to the fan track liner, the cutter is arranged towards the blades of the fan. The fan blades are rotated so that one or more of the fan blades are trimmed by the cutter. Once one or more of the fan blades have been trimmed by a desired amount, the cutter is removed from the fan track liner.