LOW NOISE AEROENGINE INLET SYSTEM

An aeroengine has an inlet system (22) which includes a deformable wall (36,38) disposed adjacent a peripheral wall (32,34) of an inlet duct (24) and a plurality of acoustic cells (40) attached to a back side (42) in fluid communication through respective holes (41) in the deformable wall (36,38) with an inlet duct air flow (11). The deformable wall (36,38) selectively forms part of the peripheral wall (32,34) of the inlet duct (24) when in an undeployed position and selectively forms a curved profile projecting into the inlet duct (24) to reduce line-of-sight noise propagation through the inlet duct (24).