Red Bull’s protest focused on how the system could the suspension or aerodynamics while on the move, which would be in breach of the series’ technical regulations.
The team said that Mercedes appeared to be using DAS “on out and slow laps as a means of adjusting tyre temperature, i.e. its primary purpose is not as a steering system but rather a tyre temperature management system.”
After a hearing involving Red Bull and Mercedes members as well as Nikolas Tombazis from the FIA’s technical department, stewards ruled that DAS was an unconventional steering system, and could be raced legally.
“As a general conclusion, it is very simple to conclude DAS would be illegal if it were not part of the steering system,” the stewards said in a statement. “So the main challenge and debate has to be on whether it can be considered to be part of the steering system. The stewards decide that DAS is a part of the steering system.
“Therefore the Stewards consider DAS to be a legitimate part of the steering system and hence to satisfy the relevant regulations regarding suspension or aerodynamic influence.”
In their decision, the stewards said that DAS uses the same hydraulically-assisted power steering system that the conventional steering does, acting on the track rod.
Red Bull is allowed to appeal the decision. Ahead of the protest, Christian Horner, the team principal said that he hoped to get the issue addressed at the beginning of the race weekend and did not want to wait until after qualifying or the race.
He since described the matter as “book closed”, although also suggested that the decision may permit Red Bull to change its front wheel settings under parc ferme conditions between qualifying and the race “with a set of spanners” rather than using the steering wheel, as Mercedes can.