As part of the new active aero regulations, there was a total of five nominated ‘straight mode’ areas around the Melbourne parklands circuit during Friday practice where the cars ran in their low downforce configuration.

They were the main straight, the run from the first chicane to Turn 3, between Turns 5 and 6, the sweeping back section between Turns 8 and 9 and the burst between Turns 10 and 11.

However on Saturday morning the governing body informed teams that the Turn 8-Turn 9 section would be dropped as a straight mode zone for safety reasons.

That was based on data and feedback that pointed to some teams struggling for downforce in straight mode through that part of the track.

“On most of the circuits these [straight mode zones] are fairly straight forward, they are in genuine straight areas of the circuit,” the FIA’s single-seater director Nikolas Tombazis told media on Saturday morning.

“On three or four circuits in the year, one of which is Melbourne unfortunately, they also include some zones which are fairly curved, as happens on the fourth straight mode zone here in Melbourne between corners 8 and 9.

“So, we had a meeting yesterday with the drivers and some expressed a concern that the downforce in that area was a bit too low, especially if they were fighting for position with other cars and they felt they could risk losing control of the car in such conditions.

“As, of course, safety is number one for us, we decided following some analysis to err on the side of caution and to remove the fourth straight mode zone here for Melbourne, starting from FP3 and of course for qualifying and in the race.”

“We are for the first time gaining detailed knowledge of the magnitude of downforce reduction, some teams are experiencing on the straight mode activation, so this is new information for us and for some of the cars that is quite a big downforce reduction, more than we had perhaps envisaged.

“This effect is not the same for all cars, but we couldn’t just act on a few cars and say, ‘well, you need to change your set-up’ and not another [car], because we wouldn’t have a robust enough criterion and it’s short notice to do that, so that’s why we felt it had to be an action for all cars and not for some cars.”

Teams have been free to design the deployment of their active aero, hence why only some cars are affected. For that same reason, the FIA isn’t expecting its last-minute decision to be universally popular.

“Some teams may argue it penalises those who have taken that factor into account, and that is true,” added Tombazis.

“But, as I say, we acted on this on the basis of safety, so we couldn’t go and say, ‘well, your car, you’re losing too much and you need to make a change, and your car is okay’.

“We didn’t feel we had a good enough criterion to do that.”