Method for locating a mark on a turbomachine casing

A method for locating a mark on the casing of an aircraft turbomachine, this casing comprising two coaxial annular shrouds, an internal shroud and an external shroud respectively, and arms which extend between the shrouds and which each comprise an inner end connected to an outer annular surface of the internal shroud and an outer end connected to an inner annular surface of the external shroud, wherein the method comprises:

• a) a step of visually inspecting the arms, the outer annular surface of the internal shroud, and the inner annular surface of the external shroud, and
• if at least one mark is detected in step a),
• b) a step of manually mounting a visual control device around the inner or outer end of one or more of the arms on which said at least one mark is detected, the or each control device being configured to cover part of the inner end of an arm and part of the outer annular surface of the internal shroud extending around that inner end, or to cover part of the outer end of the arm and part of the inner annular surface of the external shroud extending around that outer end, and
• c) a step of determining the location of said at least one mark in an area of the casing:
• said at least one mark being located in a first area of the casing, which is an area of junction of one of the arms with one of the shrouds, when said at least one mark is hidden by the control device in step b),
• said at least one mark being located in a second area of the casing, which is an area of an arm excluded from the junction areas of this arm, when said at least one mark is located on the annular surface of the shroud and is not hidden by the control device in step b), and
• said at least one mark being located in a third area of the casing, which is an area of the casing excluded from the junction areas of the arms, when said at least one mark is located on the arm and is not hidden by the control device in step b).