Method for machining an attachment flange of an aircraft turbomachine case

A method of machining an attachment flange for an aircraft turbomachine case, said method being for machining at least one of the two opposite surfaces of the flange approximately along the direction of its thickness, making use of a machining system comprising a shape follower machining module, this module being intended to follow the shape of the flange when it is moved along the circumferential direction relative to the axis of the case, the module comprising a first structure fitted with a first machining tool and a second structure fixed to the first structure, the flange being intended to be fit between the first and second structures such that said at least one of the two opposite surfaces is machined by the first machining tool, the module also comprising shape follower elements carried by the first and second structures, the method including the following steps:

• placing a machining module on the case attachment flange, with the machining tool(s) and shape follower elements in a retracted position;
• bringing the machining tool(s) and shape follower elements into contact with opposite surfaces of the flange;
• and
• displacing the machining module along the circumferential direction of the flange, displacement during which the machining module follows the shape of the flange.