A gas turbine engine comprising: a compressor section ; a combustor in fluid communication with the compressor section ; a turbine section in fluid communication with the combustor , the turbine section including a fan drive turbine and a second turbine , the fan drive turbine having exactly three turbine stages ; a fan including a plurality of blades rotatable about an axis (A); and a speed change system driven by the fan drive turbine for rotating the fan about the axis (A), wherein the fan drive turbine includes a first aft rotor attached to a first shaft and the second turbine includes a second aft rotor attached to a second shaft and an annular space is defined between the first shaft and the second shaft , wherein the compressor section comprises a first compressor driven by the fan drive turbine through the first shaft and a second compressor driven by the second turbine through the second shaft , characterised in that : a first bearing assembly is disposed axially aft of a first connection between the first aft rotor and the first shaft , wherein the first bearing assembly supports an aft portion of the first shaft , a second bearing assembly is disposed within the annular space defined between the first shaft and the second shaft , wherein the second bearing assembly supports an aft portion of the second shaft on the first shaft ; the fan has 18 or fewer blades; and a ratio between the number of fan blades and the number of fan drive turbine stages is between 2.5 and 8.5. a compressor section ; a combustor in fluid communication with the compressor section ; a turbine section in fluid communication with the combustor , the turbine section including a fan drive turbine and a second turbine , the fan drive turbine having exactly three turbine stages ; a fan including a plurality of blades rotatable about an axis (A); and a speed change system driven by the fan drive turbine for rotating the fan about the axis (A), wherein the fan drive turbine includes a first aft rotor attached to a first shaft and the second turbine includes a second aft rotor attached to a second shaft and an annular space is defined between the first shaft and the second shaft , wherein the compressor section comprises a first compressor driven by the fan drive turbine through the first shaft and a second compressor driven by the second turbine through the second shaft , characterised in that : a first bearing assembly is disposed axially aft of a first connection between the first aft rotor and the first shaft , wherein the first bearing assembly supports an aft portion of the first shaft , a second bearing assembly is disposed within the annular space defined between the first shaft and the second shaft , wherein the second bearing assembly supports an aft portion of the second shaft on the first shaft ; the fan has 18 or fewer blades; and a ratio between the number of fan blades and the number of fan drive turbine stages is between 2.5 and 8.5. a first bearing assembly is disposed axially aft of a first connection between the first aft rotor and the first shaft , wherein the first bearing assembly supports an aft portion of the first shaft , a second bearing assembly is disposed within the annular space defined between the first shaft and the second shaft , wherein the second bearing assembly supports an aft portion of the second shaft on the first shaft ; the fan has 18 or fewer blades; and a ratio between the number of fan blades and the number of fan drive turbine stages is between 2.5 and 8.5. <EOS>