A gas turbine engine is provided with a long nacelle which forms both the inlet and exhaust of the engine. The nacelle is spaced apart from a core engine to define an annular bypass duct therebetween. The incoming air stream is pressurized by a front fan disposed in the inlet and then divided between the core engine and bypass duct. A lobed mixer device is provided downstream of the core engine to intermix the core engine and bypass duct exhaust streams. The mixed streams are discharged from a common nozzle formed at the downstream end of the nacelle. A non-redundant system of mounts are provided to secure the engine to the pylon of an aircraft in such a manner as to reduce engine thrust induced bending loads and insure symmetry of these thrust loads. The total reaction of the thrust loads at the mounting points is reduced by a unique interlocking system by which all of the major engine assemblies are joined. The engine is configured such that it may be easily removed from an aircraft and replaced with a spare engine in minimum time. This quick change capability is achieved by mounting the engine such that it may be removed from the aircraft by disconnecting the forward and rear mounts and an engine bleed duct. The mid portion of the engine nacelle and all accessories mounted thereon remain with the aircraft.