Repair method for guide vanes of a gas turbine, in particular an aircraft gas turbine, comprising the following steps: providing at least one guide vane to be maintained; detecting the actual geometry of the guide vane to be maintained using at least one contactless measuring method; comparing the actual geometry of the guide vane detected by the contactless measurement method with a predetermined desired geometry (SG) for a corresponding guide vane type; calculating a target geometry (ZG) for the guide vane to be maintained, which corresponds as far as possible to the desired geometry (SG), such that, using optimization parameters, the desired geometry (SG) of the guide vane to be maintained is approximated at least in portions along its flow contour; applying material along a suction side of the flow contour of the guide vane from a leading edge to a trailing edge of the guide vane to be maintained and machine removal of applied material along a suction side of the flow contour of the guide vane from a leading edge to a trailing edge of the guide vane to be maintained, such that the calculated target geometry (ZG) is produced, characterized in that the target geometry (ZG) of the guide vane to be maintained is calculated and restored such that the flow contour in the region of the A4 cross-section (QS) of the guide vane to be maintained is approximated as effectively as possible to the flow contour of the desired geometry (SG) in the region of the A4 cross-section, the A4 cross-section (QS) being defined as the distance between two adjacent guide vanes , which extends between a central region of the suction side of the guide vane to be maintained to a region of the trailing edge of the adjacent guide vane , and in that the provided guide vane is removed from the first high-pressure turbine stage of a high-pressure turbine directly following the combustion chamber. providing at least one guide vane to be maintained; detecting the actual geometry of the guide vane to be maintained using at least one contactless measuring method; comparing the actual geometry of the guide vane detected by the contactless measurement method with a predetermined desired geometry (SG) for a corresponding guide vane type; calculating a target geometry (ZG) for the guide vane to be maintained, which corresponds as far as possible to the desired geometry (SG), such that, using optimization parameters, the desired geometry (SG) of the guide vane to be maintained is approximated at least in portions along its flow contour; applying material along a suction side of the flow contour of the guide vane from a leading edge to a trailing edge of the guide vane to be maintained and machine removal of applied material along a suction side of the flow contour of the guide vane from a leading edge to a trailing edge of the guide vane to be maintained, such that the calculated target geometry (ZG) is produced, characterized in that the target geometry (ZG) of the guide vane to be maintained is calculated and restored such that the flow contour in the region of the A4 cross-section (QS) of the guide vane to be maintained is approximated as effectively as possible to the flow contour of the desired geometry (SG) in the region of the A4 cross-section, the A4 cross-section (QS) being defined as the distance between two adjacent guide vanes , which extends between a central region of the suction side of the guide vane to be maintained to a region of the trailing edge of the adjacent guide vane , and in that the provided guide vane is removed from the first high-pressure turbine stage of a high-pressure turbine directly following the combustion chamber. <EOS>