Method of upgrading a modular gas turbine engine

A method of upgrading a modular gas turbine engine, wherein the gas turbine engine comprises:

• a first fan module comprising a fan having plurality of fan blades;
• a first engine core module including an engine core and a first gearbox arranged to provide drive to the fan;
• and a first fan case module comprising a fan case arranged to enclose the fan blades, the method including the steps of:
• disassembling the gas turbine engine,
• replacing a one of the first fan module, first engine core module or first fan case module with a replacement fan module, a replacement engine core module or a replacement fan case module;
• and
• reassembling the gas turbine engine using the replacement module, wherein the replacement module is compatible with the others of the first fan module, first engine core module or first fan case module, the replacement module is designed to different parameters to the one of the first fan module, first engine core module or first fan case module, such that the replacement module alters the performance of the engine;
• and
• replacing the first gearbox in the engine core module with a replacement gearbox prior to reassembling, the replacement gearbox being designed to different parameters to the first gearbox.

A method of upgrading a modular gas turbine engine, wherein the gas turbine engine comprises:

• a first fan module comprising a fan having plurality of fan blades;
• a first engine core module including an engine core and a gearbox arranged to provide drive to the fan;
• and a first fan case module comprising a fan case arranged to enclose the fan blades, the method including the steps of:
• disassembling the gas turbine engine,
• replacing a one of the first fan module, first engine core module or first fan case module with a replacement fan module, a replacement engine core module or a replacement fan case module;
• and
• reassembling the gas turbine engine using the replacement module, wherein the replacement module is compatible with the others of the first fan module, first engine core module or first fan case module, the replacement module is designed to different parameters to the one of the first fan module, first engine core module or first fan case module, such that the replacement module alters the performance of the engine, and the engine core module and fan module are passed off separately;
• and
• passing off the replacement module independently of the other of the first modules after reassembly of the engine.