case where the air intake structure is of the aforementioned lfc type centering members 45 can be provided fixed on the sheet 41 making it possible to center the air intake structure 1 in relation to the shroud 7 as in the case of fig6 the skin of the air intake lip 5 forms the structural skin of the panels p 1 and p 2 this structural skin being provided with perforations 6 of course different acoustic properties can be chosen for each of the panels p 1 and p 2 and the assembly of the panels p p 1 p 2 can be formed by juxtaposition and or superposition of blocks of foam possibly provided with cavities of course one may also consider replacing the sound attenuation panel p 2 made from a porous material according to the invention with a traditional sound attenuation panel of the type comprising a honeycomb structure the zone in which the panel p 2 is located being significantly less hot than the zone in which the panel p 1 is located the use of a traditional sound attenuation panel is indeed possible it will also be noted that one will preferably choose for the joint 39 a porous material having a low heat conductivity so as to correctly insulate the panel p 2 in relation to the panel p 1 a ceramic foam may for example be suitable for said joint it is understood that in the alternatives of fig6 and 7 the sheet 37 or 41 and the panel p or p 1 constitute connecting.