Abstract: The present invention relates to turbofan gas turbine engines in which the fan assembly is positioned downstream of the core engine of the turbofan gas turbine engine i.e. an aft fan turbofan. Conventional turbofan engines have the fan assembly positioned upstream of the core engine, and the core engine is mounted onto an aircraft pylon. The fan casing is then carried by the core engine. This arrangement in an aft fan would result in losses and intake distortions under side winds and aircraft yaw. The aft fan turbofan has a core engine and a fan assembly which is positioned downstream of the core engine. An upstream and downstream support means, which comprise struts, extend from a fan casing to the core engine and the fan assembly to support the core engine and fan assembly. Upstream mounting means on the fan casing and a downstream mounting means carry the turbofan engine from an aircraft pylon.