Carbon Fiber PEEK Replaces Metal in Aircraft Door Fitting

A high-modulus 40% carbon fiber-reinforced PEEK from Victrex Polymer Solutions, West Conshohoken, Penn., has replaced aluminum in a fitting of the aircraft door of Airbus Helicopters’ new Airbus A350-900.

Now manufactured from Victrex PEEK 90HMF40, the brackets have been developed by Airbus Helicopters and are in serial production for commercial use after receiving the relevant component qualification. Weight and production costs have each been reduced by 40% with the substitution of metal. The injection-molded part replaces the higher cost manufacture of the bracket machined from an aluminum block.

The fiber-reinforced polymer (FRP) structure of the A350 XWB’s aircraft door uses an outer skin coupled with a bracing structure on the inside. A fitting, now made from Victrex’s PEEK, connects the outer skin to points on the internal bracing structure. The two components form a box-type support structure to exploit the maximum geometrical moment of inertia. Commenting on the operation and significance of the PEEK component, Christian Wolf, head of airplane doors R&D at Airbus Helicopters says, “In terms of the standard load case, i.e. the internal cabin pressure, this point-type joint reduces the deformation on the outer skin, thereby maintaining the aerodynamic quality of the aircraft door. All components in the aircraft door are of a singly-reduced design. If a component near the bracket fails, the bracket will provide an alternative path for transferring structural loads and is therefore part of the aircraft’s primary structure.