An integrated propulsion system comprising components that include a gas turbine engine, a nacelle assembly, and a pylon attaching the nacelle assembly and the engine to an aircraft structure, wherein: the nacelle assembly includes a fan nacelle arranged at least partially about a fan and the engine; the system includes a fan section at least partially defined by the fan nacelle; the engine includes a turbine section configured to drive the fan section and a compressor section, the compressor section including a first compressor and a second compressor; and the fan section is configured to deliver a portion of air into the compressor section, and a portion of air into a bypass duct; characterised in that: the pylon includes a mounting assembly attachable to the nacelle assembly and the engine, the mounting assembly including a forward mount, an intermediate mount and an aft mount, wherein the forward mount is configured to react to at least a vertical load, a first side load and a torsional load relative to an axis, the intermediate mount is configured to react to at least a thrust load along the axis, and the aft mount is configured to react to at least a vertical load and a second side load; the nacelle includes the fan nacelle arranged at least partially about a core cowling to define a bypass flow path, and an aft nacelle arranged at least partially about the core cowling to define a duct, the bypass flow path extending circumferentially about the axis between opposite sides of a single bifurcation defining the duct; and the integrated propulsion system further includes a mid-turbine frame and the aft mount is attached to the mid-turbine frame. the nacelle assembly includes a fan nacelle arranged at least partially about a fan and the engine; the system includes a fan section at least partially defined by the fan nacelle; the engine includes a turbine section configured to drive the fan section and a compressor section, the compressor section including a first compressor and a second compressor; and the fan section is configured to deliver a portion of air into the compressor section, and a portion of air into a bypass duct; characterised in that: the pylon includes a mounting assembly attachable to the nacelle assembly and the engine, the mounting assembly including a forward mount, an intermediate mount and an aft mount, wherein the forward mount is configured to react to at least a vertical load, a first side load and a torsional load relative to an axis, the intermediate mount is configured to react to at least a thrust load along the axis, and the aft mount is configured to react to at least a vertical load and a second side load; the nacelle includes the fan nacelle arranged at least partially about a core cowling to define a bypass flow path, and an aft nacelle arranged at least partially about the core cowling to define a duct, the bypass flow path extending circumferentially about the axis between opposite sides of a single bifurcation defining the duct; and the integrated propulsion system further includes a mid-turbine frame and the aft mount is attached to the mid-turbine frame. the pylon includes a mounting assembly attachable to the nacelle assembly and the engine, the mounting assembly including a forward mount, an intermediate mount and an aft mount, wherein the forward mount is configured to react to at least a vertical load, a first side load and a torsional load relative to an axis, the intermediate mount is configured to react to at least a thrust load along the axis, and the aft mount is configured to react to at least a vertical load and a second side load; the nacelle includes the fan nacelle arranged at least partially about a core cowling to define a bypass flow path, and an aft nacelle arranged at least partially about the core cowling to define a duct, the bypass flow path extending circumferentially about the axis between opposite sides of a single bifurcation defining the duct; and the integrated propulsion system further includes a mid-turbine frame and the aft mount is attached to the mid-turbine frame.