PURPOSE: To reduce relative movement through vibration between the structural parts of an engine by connecting a core gas generator of a ducted fan gas turbine to a pylon through a connecting rod, and connecting the pylon through an elastic vibration absorbing device to the aircraft beam structure.

CONSTITUTION: An assembly of a pylon 14 and a ducted fan gas turbine engine is connected to an aircraft through main beams 38, 40 in a main blade. In this arrangement, a device for holding the engine in an original position is formed by a bolt 42 for fastening a flange 44 of the pylon 14 to flanges 39 of the main beams 38, 40, and a portion which can be used in a vibration absorbing structure is a connecting part between the pylon 14 and the main beams 38, 40. As the vibration absorbing structure, for example, a rubber bush or a compressed wire bush is used as a vibration absorving material in the connecting part, whereby the relative movement through vibration between the principal main casing structure parts of the gas turbine can be reduced.