Formula 1 teams can finalise the specification of their 2018 chassis after the FIA confirmed details of how the new halo cockpit protection device load test will be conducted.
Full details of the halo, which will be introduced in a grand prix for the first time next season, and the loads expected on the chassis mountings had been shared, but teams were waiting on how the 'push' test will be applied.
This impacts how the loads will be distributed through the chassis, and the complication is that the test cannot be conducted with a real halo fitted, because it would fail before the chassis mountings.
The delay in defining the test has caused frustration for some teams, particularly those whose level of resources mean that key design parameters must be frozen early.
But after talks with the teams, the FIA has now defined the test and amended the technical regulations accordingly, with the changes ratified when the World Motor Sport Council met in Paris on Thursday.
Regarding the test, the FIA says a dummy structure must be used in place of the halo.
For each test, peak loads must be applied in less than three minutes and be maintained for five seconds.
After five seconds of application there must be no failure of any part of the survival cell or of any attachment between the structure and the survival cell.
The nature of the load and the way in which it is applied, is detailed in the regulations.
The FIA added that all static and dynamic load tests must be performed with the secondary roll structure (whether dummy or otherwise) removed.
Meanwhile, the World Motor Sport Council also ratified changes to the technical regulations that instigates improvements to chassis strength and wheel retention systems for 2018.
Regarding engines, the FIA has brought forward the deadline in which manufacturers must inform the governing body of its intention to supply engines from May 6 to January 1 of the preceding year.
The next World Motor Sport Council meeting will be held on December 6 in Paris.