# US 11,111,813 B2 · Gas turbine engine maintenance method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,111,813 B2 - Document ID: US11111813B2 - Status: Granted - Kind: B2 - Application number: 15/370,360 - Filed: 2016-12-06 - Published: 2018-06-07 - Granted: 2021-09-07 - Earliest claimed: 2016-12-06 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Mehmet M. Dede; Byron Andrew Pritchard, Jr.; Wayne Ray Grady; Ambarish Jayant Kulkarni - Web page: https://patentgrep.com/patent/US11111813B2 ## CPC - F01D 21/003: {Arrangements for testing or measuring (for measuring vibrations G01H)} - B05D 1/02: performed by spraying - B05D 5/005: {Repairing damaged coatings} - F02C 3/04: having a turbine driving a compressor (power transmission arrangements F02C7/36; control of working fluid flow F02C9/16) - G01M 15/14: Testing gas-turbine engines or jet-propulsion engines - F05D 2220/32: in gas turbines - F05D 2230/72: Maintenance - F05D 2230/90: Coating; Surface treatment - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02) - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A method for inspecting a gas turbine engine using a maintenance tool includes assembling a plurality of rail segments of a rail system of the maintenance tool within a core air flowpath of the gas turbine engine. The gas turbine engine includes a compressor section, a combustion section, and a turbine section together defining at least in part the core air flowpath. The method also includes moving a maintenance head of the maintenance tool along the plurality of rail segments of the rail system to perform maintenance operations within the core air flowpath of the gas turbine engine. ## Claims ### Claim 1 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 moving a maintenance head of the maintenance tool along an exterior 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. ### Claim 2 (depends on 1) The method of claim 1, further comprising: taking an image of one or more components of the gas turbine engine within the core air flowpath of the gas turbine engine with one or more cameras of the maintenance head of the maintenance tool. ### Claim 3 (depends on 2) The method of claim 2, wherein the moving of the maintenance head of the maintenance tool along the plurality of rail segments of the rail system comprises determining a location of the maintenance head, and wherein the taking of the image of the one or more components of the gas turbine engine comprises recording the location of the maintenance head that was determined when the image was taken. ### Claim 4 (depends on 2) The method of claim 2, wherein the taking of the image of the one or more components of the gas turbine engine within the core air flowpath of the gas turbine engine comprises taking a plurality of images of the one or more components of the gas turbine engine at different locations along a length of the rail system. ### Claim 5 (depends on 4) The method of claim 4, wherein the moving of the maintenance head of the maintenance tool along the exterior of the plurality of rail segments of the rail system comprises determining a location of the maintenance head, and wherein the taking of the plurality of images of the one or more components of the gas turbine engine at the different locations along the length of the rail system comprises determining and recording the respective location of the different locations of the maintenance head for each of the plurality of images. ### Claim 6 (depends on 1) The method of claim 1, wherein the moving of the maintenance head of the maintenance tool along the exterior of the plurality of rail segments of the rail system comprises moving the maintenance head of the maintenance tool using an actuation device of the maintenance tool. ### Claim 7 (depends on 6) The method of claim 6, wherein the actuation device is a pulley system including a spool, a first line, and a second line, and wherein the moving of the maintenance head of the maintenance tool using the actuation device comprises rotating the spool of the pulley system about a central axis of the spool. ### Claim 8 (depends on 7) The method of claim 7, wherein the first and second lines of the pulley system are each attached to the maintenance head, wherein the rotating of the spool of the pulley system about the central axis of the spool comprises retracting the first line at a first speed and extending the second line at a second speed, and wherein the first speed is equal to the second speed. ### Claim 9 (depends on 7) The method of claim 7, wherein the rotating of the spool of the pulley system about the central axis of the spool comprises determining a location of the maintenance head based at least in part on an amount of rotation of the spool of the pulley system. ### Claim 10 (depends on 1) The method of claim 1, wherein the plurality of segments of the rail system extend three hundred and sixty degrees (360°) within the core air flowpath after the assembling within the core air flowpath, and wherein the moving of the maintenance head of the maintenance tool along the exterior of the plurality of rail segments of the rail system comprises moving the maintenance head three hundred and sixty degrees (360°) along the plurality of rail segments of the rail system. ### Claim 11 (depends on 1) The method of claim 1, wherein the inserting the plurality of rail segments of the rail system comprises inserting each of the plurality of rail segments sequentially through the individual inspection hole. ### Claim 12 (depends on 1) The method of claim 1, wherein the assembling of the plurality of rail segments of the rail system mounting the rail system within the core air flowpath further comprises fixing each of the plurality radial clamps to a casing of the gas turbine engine. ### Claim 13 (depends on 1) The method of claim 1, wherein the assembling of the plurality of rail segments of the rail system further comprises assembling the plurality of rail segments of the rail system within a combustor of the combustion section of the gas turbine engine. ### Claim 14 (depends on 1) The method of claim 1, wherein the assembling of the plurality of rail segments of the rail system within the core air flowpath of the gas turbine engine is completed while the gas turbine engine is completely assembled. ### Claim 15 (depends on 1) The method of claim 1, further comprising: spraying one or more components of the gas turbine engine with a coating using the maintenance head. ### Claim 16 (depends on 15) The method of claim 15, wherein the spraying of the one or more components of the gas turbine engine with the coating using the maintenance head comprises spraying the one or more components of the gas turbine engine with the coating through one or more spray nozzles of the maintenance head. ### Claim 17 (depends on 1) The method of claim 1, further comprising: disassembling the plurality of rail segments of the rail system of the maintenance tool. ### Claim 18 (depends on 17) The method of claim 17, wherein the disassembling of the plurality of rail segments of the rail system of the maintenance tool comprises removing the plurality of rail segments of the rail system from the core air flowpath sequentially through the individual inspection hole. ### Claim 19 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. ### Claim 20 (depends on 1) The method of claim 1, wherein the plurality of radial clamps extend into the core air flowpath.