Abstract: The present invention comprises a cowling structure for a gas turbine aircraft engine which allows the aerodynamic characteristics of the inlet passageway to the engine to be varied in accordance with flight conditions. This structure includes an annular lip portion positioned at the front edge of the cowling defining an aerodynamically sharp contour and which is mounted on a set of support struts constructed for allowing the lip portion to be translated forwardly and backwardly from the forward edge of the cowling. The structure further comprises a mechanism for injecting pressurized air into the airflow along the trailing edges of these support struts in order to suppress turbulence induced in tha airflow such that noise as may be produced as a result of airflow is substantially decreased.