This design change will introduce structural provisions for the installation of a low profile LBand dual element antenna on the upper fuselage skin of 757 aircraft.

The provisions will consist of internally mounted nutplates and strengthening doubler plate, the design of the doubler installation will be based on SRM repairs for this area of the aircraft skin. A cover/blanking plate will be mounted to the external fuselage; this will be removable to permit the installation of an L-Band antenna. The installation of the L-Band antenna will be under a separate design change but will be included in the structural analysis for this design change.

A damage tolerance assessment, along with static and fatigue analysis, will be carried out to determine the required structural inspection intervals for the installation to ensure continued airworthiness.

The installed blank plate will be tested in accordance with standard practices to ensure it is appropriately electrically bonded to the airframe.

-       Reduced area of antenna

-       Reduced drag force on the antenna

-       Better fuel economy