Max Verstappen and Pierre Gasly only just made it out of the Barcelona pitlane before it closed 30 minutes before the start of the race because the two Honda-powered teams were waiting for the fuel to rise to the legal minimum temperature.
The limit is 10C below ambient temperature as declared to the nearest round number by the FIA from the official timing screens two hours before the start. That coincides with the time when the fuel has to go into the cars.
Teams put fuel in at a level below the minimum, on the basis that the temperature will rise while it sits in the car in the two hours before the race and rise further, when the engines are started and run, as part of the usual pre-race procedures.
The official temperature shown around two hours before the Spanish GP on the FIA info system was in the 34C range, so teams thus expected to have to use 24C as the minimum.
However, the actual official figure declared by the FIA, and to which teams had to adhere, apparently just ticked to 35C – which meant fuel had to be 25C or over.
That difference was enough to leave some teams scrambling to generate the extra degree of fuel temperature at the last minute. The FIA monitors this live from the standard fuel flow meters in each car.
In Spain, Red Bull and AlphaTauri used the time that they would usually use for laps through the pitlane and a practice start to keep the cars in the garages with their engines running.
Gasly and Verstappen finally left just seconds before the pitlane closed and were able to get to the grid. However, the drivers’ usual pre-race preparations were compromised.
Teams are now discussing when the official temperature is declared with the FIA, with the main issue being that fuel has to go into the cars essentially at the same time – two hours before the race schedule – as the official temperature declaration.
Some teams have suggested that the temperature should be made official earlier to give them more time to make the required calculations. That discussion is now ongoing and any changes will have to be agreed and approved via the usual processes.
In Miami the two Aston Martins were so far off the minimum temperature, due to a team error, that they were obliged to start from the pitlane once the minimum limit had been reached.
Speaking in Monaco on Thursday, Gasly admitted he thought the same might happen to him in Spain and made it clear how tight his departure from the garage had been.
"I mean I'm not gonna lie, at some point I could see the clock and I was like, it would be great to go," Gasly said. "We made it by about 20 seconds.
"The thing is we kind of laughed about it before the race, about this [Aston Martin] fuel story that happened in Miami. And then we ended up in the same situation. I'm glad we managed to sort everything out.
"It doesn't impact but it's just a small thing which we can avoid and give an easier time to all the guys. We were supposed to do two laps to the grid, check the balance do a practice start. In the end we didn't do the practice start, didn't check the balance.
"It doesn't change the full race, I had a great start, didn't have the best balance, but it wasn't the reason. It's just a lot of things which can be improved."
