Gas turbine engine maintenance method

A method for maintaining a gas turbine engine using a maintenance tool, the gas turbine engine having a compressor section, a combustion section, and a turbine section in serial flow order and together defining at least in part a core air flowpath, the gas turbine engine defining a plurality of inspection holes spaced circumferentially about the gas turbine engine, the method comprising:

• assembling a plurality of rail segments of a rail system of the maintenance tool within the core air flowpath of the gas turbine engine, the plurality of rail segments connected to one another;
• and
• sliding a maintenance head of the maintenance tool along an exterior surface of the plurality of rail segments of the rail system to perform maintenance operations within the core air flowpath of the gas turbine engine,
• wherein the assembling of the plurality of rail segments of the rail system comprises inserting the plurality of rail segments of the rail system through an individual inspection hole of the plurality of inspection holes and mounting the rail system within the core air flowpath by fixing a plurality of radial clamps to the rail system, the plurality of radial clamps extending through respective holes of the plurality of inspection holes.