Gas turbine engine disassembly/assembly methods

A method for assembling a gas turbine engine, comprising:

• providing an aircraft and a gas turbine engine assembly installed with the aircraft, the gas turbine engine assembly including a compressor rotor, a combustor, a turbine rotor, a forward portion of a static structure and a bypass duct, the forward portion of the static structure housing and supporting the compressor rotor, the combustor and the turbine rotor, the bypass duct including an inner duct wall, an outer duct wall and a bypass flowpath formed radially between the inner duct wall and the outer duct wall, and the outer duct wall axially overlapping the combustor, the turbine rotor and the forward portion of the static structure;
• providing a turbine support structure at a location outside of the aircraft, the turbine support structure previously assembled then disconnected from the gas turbine engine assembly;
• providing a second turbine rotor at the location outside of the aircraft, the second turbine rotor previously assembled then disconnected from the gas turbine engine assembly;
• reassembling the turbine support structure with the gas turbine engine assembly such that the turbine support structure is fastened to the forward portion of the static structure and the outer duct wall axially overlaps the turbine support structure;
• and
• reassembling the second turbine rotor with the gas turbine engine assembly, wherein the turbine support structure is arranged axially between the turbine rotor and the second turbine rotor following the assembling of the second turbine rotor;
• wherein the outer duct wall remains installed during the step of reassembling the turbine support structure with the gas turbine engine assembly.