The FIA has told Renault Sports F1 that it must change the design of its rear wing before the Australian Grand Prix.
The sport's governing body has been conducting checks on all cars taking part in the four-day pre-season testing at the Circuit de Barcelona-Catalunya this week.
The focus is believed to be mainly on the design of active suspension systems on the new 2017 cars. However it was a different element on the Renault that caught the eye of officials.
In Renault's case it's the design of the support pillar for the rear wing. The current design sees the wing attached to the DRS actuator pod rather than the main plane of the car.
The further forward the pillar is attached, the better the aerodynamic advantage. That's because there is less interference to the air flow into the rear wing.
However Renault's innovative approach seems to put the car in breach of Article 3.9.6 of Formula One's Technical Regulations. This requires the support to be extended until it meets the area of the regulations covering the area of the rear wing main plane.
The attachment was reviewed after comments from pitlane rivals. However other teams are not thought to be too worried about it. It's believed any benefit to the car's performance will be minimal.
Most teams are looking into new approaches in this area. In previous seasons Red Bull and Ferrari adopted a swan-neck style support, similar to the way WEC cars tackle the same problem.
Renault will be able to continue using the current design for pre-season testing. However they will have to make changes to the rear wing support before the start of the season.