A gas turbine engine includes an engine core; a fan located upstream of engine core and having a fan diameter; a nacelle surrounding engine core and defining a bypass duct between engine core and nacelle; and a fan OGV extending radially across bypass duct, fan OGV having a radially inner and outer edge, wherein the radially inner edge's axial midpoint is the fan OGV root centrepoint. The engine core includes a compressor system encompassing a first, lower pressure, compressor, and second, higher pressure, compressor; and an outer core casing surrounding the compressor system and including a first flange connection arranged to allow separation of outer core casing at an axial position of first flange connection, the first flange connection having a first flange radius, wherein the first flange connection is downstream of an axial position. A fan OGV root position ratio of: axial ⁢ ⁢ distance ⁢ ⁢ between ⁢ ⁢ the ⁢ ⁢ first ⁢ ⁢ flange ⁢ ⁢ connection and ⁢ ⁢ the ⁢ ⁢ fan ⁢ ⁢ OGV ⁢ ⁢ root ⁢ ⁢ centrepoint ⁢ first ⁢ ⁢ flange ⁢ ⁢ radius is equal to or less than 2.6.