For many, Friday's free races at the Russian Grand Prix began with the replacement of the power plant elements.
Eight pilots had to update their engines at once to participate in the tenth stage of the season.
Among those whose cars have undergone changes were the championship leader Lewis Hamilton and Daniil Kvyat.
The Russian pilot had to install new engines, turbines and motor generators.
Each of these elements was the last on the list of allowed replacements for the AlphaTauri rider, so the next breakdown would result in a penalty on the grid.
Usually in Sochi, teams give a chance to work for their reserve riders, but this year, during Friday's free races, only combat pilots were behind the wheel.
Many of them needed to test new items and check their effectiveness.
In addition, the softest tire sets were chosen for the Russian Grand Prix, and their evaluation was also extremely necessary.
It had to be carried out in conditions of low adhesion, for which Sochi Autodrom is famous.
Carlos Sainz was the first to experience the harsh nature of the track.
The McLaren pilot took off in the seventh turn and the rear of the car crashed into the bump stop.
The Spaniard was able to return to the pits on his own, but his rear wing was hopelessly damaged and he never showed up from the pits.
Soon, Nicholas Latifi got into an accident at the difficult 10th turn, and the session even had to be interrupted for a short time with red flags.
Kvyat and Romain Grosjean also experienced problems with braking and skids, but they avoided any consequences for their cars.
But for Hamilton, everything turned into a small disaster.
Almost every blockage of tires led to their damage.
As a result, the reigning world champion was unable not only to collect the necessary data, but also to drive the fastest lap at full strength.
Yellow flags after the accident of Sainz also prevented him, because of which it was not possible to accelerate when the moment was right.
As a result, the Mercedes driver took only 19th place, surpassing only Latifi in the best time.
It was not easy to curb the track, and his partner Valtteri Bottas, but he still showed the best time in the first training session.
The second, quite unexpectedly, was Daniel Riccardo in Renault, who was 0.507 seconds behind the Finn.
The third was Max Verstappen.
Behind him were both Racing Point drivers, with Sergio Perez ahead of Lance Stroll.
The Mexican counted on updates in Sochi and did not receive them due to the Canadian's accident at the Tuscany Grand Prix, but still turned out to be faster than his partner.
Kvyat took seventh place high for himself.
At the same time, the Russian rode on medium-hardness tires, while all the rivals ahead of him used the softest compound.
Behind the owner of the track were Alexander Albon in Red Bull, and Sebastian Vettel in Ferrari, and team-mate Pierre Gasly.
In the second session of free races, there were no serious accidents, especially since the Formula 2 qualification improved the grip of the track.
But the racers continued to fly to the sidelines.
This time Stroll and Hamilton did not cope with the 13th turn, and the championship leader drove a few centimeters from the barrier.
The accident could greatly reduce his chances of repeating Michael Schumacher's record for victories in Formula 1 next Sunday.
Otherwise, the Briton felt good on the Sochi track and showed the final second time, losing only to Bottas, who, in turn, dropped more than a second from his morning result.
Riccardo performed great in the second training session.
He was still ahead of everyone except the Mercedes drivers.
At the same time, Sainz and his partner Lando Norris got close to the Australian.
Verstappen could press Riccardo, but he very inappropriately touched the curb on his fastest lap and was left with seventh time.
Kvyat was not so fast on Friday afternoon.
He not only dropped to 13th place, but also lost a quarter of a second to Gasley.
Nevertheless, the Russian pilot noted that in Saturday's qualification he will be ready to fight for getting into the top ten.
At the same time, he noted that during the weekend the temperature will rise and this will affect the remaining arrivals.
“Today we worked on some things and I was pleased with the number of laps completed.
There is still a bit more work to be done on the balance sheet, but Friday is just to try and get things right by Saturday.
It will be pretty hot this weekend, so we will do our best to get the most out of the car in all conditions.
If we cope with our task this evening and tomorrow morning, then I see no reason why we would not be able to compete for getting into the third qualification segment, ”Kvyat shared his expectations.