Concorde had livery restrictions; the majority of the surface had to be covered with a highly reflective white paint to avoid overheating the aluminium structure due to heating effects from supersonic flight at Mach 2. The white finish reduced the skin temperature by 6 to 11 °C (11 to 20 °F).[117] In 1996, Air France briefly painted F-BTSD in a predominantly blue livery, with the exception of the wings, in a promotional deal with Pepsi.[118] In this paint scheme, Air France was advised to remain at Mach 2 (2,120 km/h; 1,320 mph) for no more than 20 minutes at a time, but there was no restriction at speeds under Mach 1.7. F-BTSD was used because it was not scheduled for any long flights that required extended Mach 2 operations.[119]