Doc 41 - Parts and Parameters been replaced and or changed during Parc Fermé

This report from the FIA Formula One Technical Delegate, Jo Bauer, details the parts and parameters that were replaced or changed during Parc Fermé on December 6th and 7th, 2025, in accordance with Article 40.3 of the 2025 Formula One Sporting Regulations. These changes were approved by the FIA technical delegate following written requests from the respective teams.

Summary of Replaced/Changed Parts:

• McLaren Mercedes (Car 81): RHS rear brake duct cascade
• Ferrari (Car 16):
  • Pop-off valve actuator
  • Front brake master cylinder
  • Parameter changes associated with the above parts replacement
• Mercedes (Car 63):
  • RHS rear inner brake duct bulkhead
  • Input shaft support bearing seal
• Aston Martin Aramco Mercedes (Car 18):
  • Headrest
  • RHS floor edge wing bracket
• Alpine Renault (Car 43): Forward plank section (with the same skids used during Q)
• Williams Mercedes:
  • Car 23: RHS front lower brake duct deflector
  • Car 55: LHS front lower brake duct deflector, RHS front lower brake duct deflector
• Kick Sauber Ferrari (Car 27): LHS rear view mirror assembly

All replacements and changes were made with the necessary approvals.