Abstract: A turbofan gas turbine engine (10) comprises a fan rotor and a compressor rotor (62). The fan rotor (24) carries a plurality of circumferentially spaced radially outwardly extending fan blades (26). The compressor rotor carries a plurality of circumferentially spaced radially outwardly extending compressor blades (64). The fan rotor (24) is mounted on a fan shaft (38) and the compressor rotor (62) is mounted on a compressor shaft (68). The compressor shaft (68) is arranged around the fan shaft (38). The fan rotor (24) is rotatably mounted on a support structure (40) by a first bearing (50) and the compres˜sor rotor (62) is rotatably mounted on the support structure (40) by a second bearing (58) spaced axially from the first bearing (50). The fan and compressor rotors (24,62) are normally arranged coaxially with each other and with the support structure (40).