Gilhome joined the Faenza-based outfit in July 2013, having previously also worked as principal aerodynamicist at Mercedes and group leader of aerodynamics at BMW Sauber.

The Australian worked closely with technical director James Key in developing the team's recent contenders, and had been focused for several months on the Honda-powered STR13.

The reasons for his departure have not been revealed by the team, nor has it been confirmed whether deputy head of aerodynamics Ben Mallock will step up replace Gilhome or someone else will be brought in to take over his responsibilities.

There will also be a change of race engineers this year too, with long-time Carlos Sainz engineer Marco Matassa having moved to Ferrari over the winter to work with its young driver development programme.

Toro Rosso is switching to Honda engines this year and its new chassis passed its crash tests on Tuesday, with the team celebrating the achievement at the factory.