Gas turbine engine with core mount

A gas turbine engine for an aircraft comprising:

• an engine core comprising:
• a compressor system with compressor blades comprising respective aerofoils, the compressor system comprising a first, lower pressure, compressor, and a second, higher pressure, compressor;
• and
• an outer core casing surrounding the compressor system and comprising:
• a first flange connection arranged to allow separation of the outer core casing at an axial position of the first flange connection, the first flange connection having a first flange radius, wherein the first flange connection is the first flange connection that is downstream of an axial position defined by the axial midpoint between the mid-span axial location on the trailing edge of the most downstream aerofoil of the first compressor and the mid-span axial location on the leading edge of the most upstream aerofoil of the second compressor, and
• a front mount arranged to be connected to a pylon, and a fan located upstream of the engine core, the fan comprising a plurality of fan blades and having a fan diameter diameter;
• wherein a front mount position ratio of:
• axial
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• distance
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• between
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• the
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• first
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• flange
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• connection
• and
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• the
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• front
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• mount
• first
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• flange
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• radius
• is equal to or less than 1.18.