Both the Airbus A350 and the Boeing 787 consist of composite materials in more than 50% of their overall structures. The motivation for using composite materials is because they possess superior properties when compared to metallic materials, such as lighter weight, better corrosion and fatigue resistance, and lower thermal expansion.
Airbus suggested Boeing’s use of composite materials for the 787 fuselages was premature, and that the new A350 XWB was to feature large carbon fiber panels for the main fuselage skin. After facing criticism for maintenance costs, Airbus confirmed in early September 2007 the adoption of composite fuselage frames for the aircraft structure. The composite frames would feature aluminum strips to ensure the electrical continuity of the fuselage (for dissipating lightning strikes). Airbus used a full mockup fuselage to develop the wiring, a different approach from the A380, on which the wiring was all done on computers.
In the development phase, the A350 systems were tested and monitored by the Dutch innovation company called Netherlands Aerospace Centre (NLR). They developed the In-Flight Lightning Damage Assessment System (ILDAS) for this purpose. ILDAS is a special measurement system that records the lightning currents on airborne commercial aircraft. For this system, NLR developed the advanced measurement electronics that convert electrical signals into digital data, placing the sensors on the inside of the cabin.
The challenge for ILDAS’s designers and developers was to devise a system that would not fail at the critical moment, thus recording accurate measurements during lightning strikes. This was accomplished during the icing test flights. NLR constructed 13 data acquisition units for the A350 prototype, which were installed throughout the fuselage and measured the electrical and magnetic fields. When the system detected that lightning struck the aircraft, all units immediately conducted highly synchronized measurements, and then quickly saved the data before the next occurrence.