Abstract: The arrangement of a gas turbine engine suitable for high bypass ratio aircraft engines in which gases circulate in a primary air channel (7) and a secondary channel (8) concentric to said primary air channel, is characterized in that structural vanes (22) connecting the channel delimitation casings (2, 10, 14, 5) with each other, alternate with aerodynamic vanes (20) for guiding the gases on a common circumference of the engine bypass air channel (8), and in that the structural channels branch out between the two channels. The resulting advantages are simplicity of construction associated with a reduction in the space required for housing the channels and good resistance without notable increase of the total mass.