A gas turbine engine comprising: - a fan mounted to rotate about a main longitudinal axis and generating a core airflow and a bypass airflow; - a core duct, across which the core airflow flows; - an engine core, comprising in axial flow series a compressor, a combustor, and a turbine coupled to the compressor through a shaft; - an Engine Section Stator comprising a plurality of ESS vanes arranged in the core duct downstream of the fan, each one of the plurality of ESS vanes comprising an external surface washed by the core airflow; - an ESS heating system adapted to heat the ESS vanes; and - a reduction gearbox that receives an input from the shaft and drives the fan at a lower rotational speed than the shaft, wherein the compressor comprises a first stage at an inlet comprising a first rotor with a row of first blades extending chordwise from a leading edge to a trailing edge, and spanwise from a root to a tip for a span height, wherein 0 % of the span height corresponds to the root and 100 % of the span height corresponds to the tip; wherein the ratio of a maximum leading edge radius (R1max) of the first blades to a leading edge radius (R1 50%) of the first blades at 50% span height is comprised between 1.0 and 2.2; and wherein the gas turbine engine further comprises: - a temperature sensor adapted to detect the temperature of the external surface of at least one of the plurality of ESS vanes and send a signal to the ESS heating system when said temperature is below a reference temperature, and wherein upon detection and/or inference of ice crystal conditions and receiving from the temperature sensor the signal that the temperature is below the reference temperature, the ESS heating system is activated to heat at least a portion of the external surface of the ESS vanes and characterised in that the ESS heating system is activated to promote melting and adhering of ice crystals on said portion of the external surface of the ESS vanes. - a fan mounted to rotate about a main longitudinal axis and generating a core airflow and a bypass airflow; - a core duct, across which the core airflow flows; - an engine core, comprising in axial flow series a compressor, a combustor, and a turbine coupled to the compressor through a shaft; - an Engine Section Stator comprising a plurality of ESS vanes arranged in the core duct downstream of the fan, each one of the plurality of ESS vanes comprising an external surface washed by the core airflow; - an ESS heating system adapted to heat the ESS vanes; and - a reduction gearbox that receives an input from the shaft and drives the fan at a lower rotational speed than the shaft, wherein the compressor comprises a first stage at an inlet comprising a first rotor with a row of first blades extending chordwise from a leading edge to a trailing edge, and spanwise from a root to a tip for a span height, wherein 0 % of the span height corresponds to the root and 100 % of the span height corresponds to the tip; wherein the ratio of a maximum leading edge radius (R1max) of the first blades to a leading edge radius (R1 50%) of the first blades at 50% span height is comprised between 1.0 and 2.2; and wherein the gas turbine engine further comprises: - a temperature sensor adapted to detect the temperature of the external surface of at least one of the plurality of ESS vanes and send a signal to the ESS heating system when said temperature is below a reference temperature, and - a temperature sensor adapted to detect the temperature of the external surface of at least one of the plurality of ESS vanes and send a signal to the ESS heating system when said temperature is below a reference temperature, and wherein upon detection and/or inference of ice crystal conditions and receiving from the temperature sensor the signal that the temperature is below the reference temperature, the ESS heating system is activated to heat at least a portion of the external surface of the ESS vanes and characterised in that the ESS heating system is activated to promote melting and adhering of ice crystals on said portion of the external surface of the ESS vanes.