After a series of FIA checks, rule clarifications and accusations from rival teams, Ferrari is confident it has proved its power unit was legal in 2019.
The Italian team enjoyed a significant straight-line speed advantage over its rivals all year, leading to speculation over the way it was running its engine. F1's power unit regulations are relatively mature and as a result there was a degree of surprise and suspicion when Ferrari gained a clear advantage over the other three manufacturers -- Mercedes, Renault and Honda -- this year.
Accusations peaked at the U.S. Grand Prix when Ferrari suddenly struggled for performance just days after racing's governing body, the FIA, issued a Technical Directive (TD) that ruled out certain ways of increasing fuel flow beyond the permitted amount.