Airbus's decision to switch the fuselage frames from aluminium to carbonfibre has eliminated one advantage that the former offered - the provision of a natural "electrical system network" throughout the fuselage to dissipate lightning strikes and to provide a current return path for systems.
A350 XWB chief engineer Gordon McConnell says that Airbus has modelled how to retain the electrical continuity with the switch to carbonfibre and decided "to fit metallic strips around the frames, which gives an equivalent electrical network to a metallic frame".
McConnell says the switch to carbon frames is "relatively weight-neutral" as any savings from the lighter material is offset by the need to add the metallic strips. The move addresses concerns about corrosion risks between the metallic frames and carbonfibre fuselage panels.
"Our customers saw this as a disadvantage as there would have be a cost later on in the aircraft's life to access this area to carry out inspections," says McConnell.