An aerofoil array for a gas turbine system, the array comprising: a) an inner annular platform and an outer annular platform, which extend about a longitudinal axis and radially delimit an annular channel for a gas flow; b) a plurality of aerofoils, which are housed in said annular channel, are arranged at a substantially constant pitch about said longitudinal axis and are constituted by: - respective central portions (7a, 7c) having a radial extension equal to at least 60% of the radial height of said aerofoils, - respective outer radial ends, each defining a connecting portion that joins the corresponding central portion with said outer annular platform, and - respective inner radial ends, each defining a connecting portion that joins the corresponding central portion with said inner annular platform; said aerofoils comprising first aerofoils and second aerofoils extending along first and, respectively, second directions (6a, 6c), which are substantially radial with respect to said longitudinal axis; said second aerofoils having at least one different geometrical feature with respect to said first aerofoils, in order to intentionally vary the eigenfrequencies of the second aerofoils with respect to those of the first aerofoils; said first and second aerofoils (5a, 5c) being arranged about said longitudinal axis with a sequence that is regularly repeated all along said annular channel; on sectioning the central portions (7a, 7c) of said first and second aerofoils (5a, 5c) with a curved sectional surface corresponding to the theoretical trajectory of the gas flow at any given radius, with respect to said longitudinal axis, the cross-sections of said central portions (7a, 7c) are the same; said first and second directions (6a,6c) defining the directions in which the airfoil cross-sections are stacked; characterised in that said different geometrical feature is defined by the curvature and/or inclination of said second directions, with respect to the one of said first directions; the different curvature and/or inclination of said directions (6a,6c) resulting in a translation of the airfoil cross sections so that some zones of the aerofoils (5a,5c) have a slight shifting in the angular pitch and/or a slight staggering in the axial direction between the leading edges and between the trailing edges. a) an inner annular platform and an outer annular platform, which extend about a longitudinal axis and radially delimit an annular channel for a gas flow; b) a plurality of aerofoils, which are housed in said annular channel, are arranged at a substantially constant pitch about said longitudinal axis and are constituted by: - respective central portions (7a, 7c) having a radial extension equal to at least 60% of the radial height of said aerofoils, - respective outer radial ends, each defining a connecting portion that joins the corresponding central portion with said outer annular platform, and - respective inner radial ends, each defining a connecting portion that joins the corresponding central portion with said inner annular platform; said aerofoils comprising first aerofoils and second aerofoils extending along first and, respectively, second directions (6a, 6c), which are substantially radial with respect to said longitudinal axis; said second aerofoils having at least one different geometrical feature with respect to said first aerofoils, in order to intentionally vary the eigenfrequencies of the second aerofoils with respect to those of the first aerofoils; said first and second aerofoils (5a, 5c) being arranged about said longitudinal axis with a sequence that is regularly repeated all along said annular channel; on sectioning the central portions (7a, 7c) of said first and second aerofoils (5a, 5c) with a curved sectional surface corresponding to the theoretical trajectory of the gas flow at any given radius, with respect to said longitudinal axis, the cross-sections of said central portions (7a, 7c) are the same; said first and second directions (6a,6c) defining the directions in which the airfoil cross-sections are stacked; characterised in that said different geometrical feature is defined by the curvature and/or inclination of said second directions, with respect to the one of said first directions; the different curvature and/or inclination of said directions (6a,6c) resulting in a translation of the airfoil cross sections so that some zones of the aerofoils (5a,5c) have a slight shifting in the angular pitch and/or a slight staggering in the axial direction between the leading edges and between the trailing edges. - respective central portions (7a, 7c) having a radial extension equal to at least 60% of the radial height of said aerofoils, - respective outer radial ends, each defining a connecting portion that joins the corresponding central portion with said outer annular platform, and - respective inner radial ends, each defining a connecting portion that joins the corresponding central portion with said inner annular platform;