Gas turbine engine casing arrangement

A method of accessing an interior of a gas turbine engine having a casing including a plurality of interconnected casing segments, the method comprising:

• decoupling a gearbox casing segment having a gearbox from a bearing housing by decoupling mating flanges of the gearbox casing segment and the bearing housing;
• and
• removing the gearbox casing segment and the gearbox to access the interior of the engine.

A method of assembling a gas turbine engine, comprising:

• forming a casing of the gas turbine engine from a plurality of casing segments, including mounting a gearbox casing segment to a bearing housing to position the bearing housing substantially within the casing, the gearbox casing segment being mounted to the bearing housing by attaching mating flanges of the gearbox casing segment and the bearing housing, the mating flanges extending radially outwardly from the casing.