Free practice 3

Hello and welcome to ESPN's live coverage of the Russian Grand Prix.

We're having a few technical problems out here in Sochi, which is why the layout of the page looks a little different, but you can still send in your comments by good old-fashioned email.

Hopefully the teams won't experience any technical difficulties as they will need every minute of this session to gather as much data as possible on the slick tyres that they were unable to test yesterday. A spillage of diesel ahead of FP1 rendered the morning session useless and rain in the afternoon limited the teams to dry running. Lewis Hamilton, for example, has yet to turn a wheel on the slick tyres.

The session is underway and a queue of cars stream out onto the circuit as the pit lane goes green.

The suspicion in the paddock is that Mercedes will retain its advantage here, but there is a bit of an unknown as it's the first time the soft and super-soft have been used since Ferrari's surprise victory in Singapore last month. This session should give a hint of the order, but with long-run data also in short supply don't read too much into the headline times.

Kvyat starts a lap on the super-soft tyres. There's a bit of extra pressure for him here in front of his home fans.

Only Rosberg, Vettel and Raikkonen remain in the pits as everyone else gets down to work.

Times coming in thick and fast now, with Bottas leading the way on a 1:42.829

Yesterday the lack of on-track action meant even more focus than usual was on Red Bull and its engine issues for next year. Nothing is sorted yet, but it seems Ferrari is losing patience and no longer wants to supply the team. That leaves a potential continuation with Renault, although relations between the two are still very frosty. Bernie insists the situation is all in hand, but time is running out.

Bottas remains fastest, 1.061s clear of Ricciardo in second.

In other news, Ferrari has a bat in its garage.

Bottas improves again to set a 1:40.884 on the soft tyres.

Hulkenberg complains of understeer in his Force India. That's likely to be a common problem here as the track surface doesn't offer up much grip and will be "green" following yesterday's rain.

Rohan asks: "ALO would start from the back of the grid? Am I correct? He is serving 25 places penalty?"

He actually has a 35-place penalty. McLaren installed a new upgraded Honda PU for FP1, but decided not to run it for the rest of the weekend as they are saving it for later in the season. That resulted in a 25-place penalty and the change back resulted in 10 more places. Unless somebody else incurs some penalties, Alonso will indeed be starting from the back of the grid at his 250th race.

The two McLarens are the only cars in the garage at the moment.

Another question from Rohan: "We are having a debate within who is going to be faster MER or FER? MER getting the advantage back due to two long straights as mentioned by you. Thus, who according to you can hold better chance to score the fastest lap? HAM or VET for say? Or maybe WIL."

I think Mercedes will have the edge here, partly due to the long straights, but also because the car is pretty well sorted in the corners. The only thing that might cause issues is if they struggle to get the tyres switched on again. In Singapore it seemed they were not generating the bulk temperature they needed in the tyre due to the lack of high-speed corners, but Sochi is a bit quicker and I think they will be better here.

A replay shows Kimi Raikkonen locking up on entry to the penultimate corner and running wide and off the track.

Bottas remains fastest, 0.355s faster than team-mate Felipe Massa.

Verstappen spins out in the final corner. He appeared to carry a bit too much speed into the corner and the back of the car overtook the front. He gets the Toro Rosso going again - no damage done.

Hamilton is over two seconds off Bottas, but that is a perfect example of different teams chasing different run plans in order to learn what they need to know about these tyres. There's a big variation in fuel loads out there.

Rohan asks: "BOT scored a podium last year. How different or same is it going to be for WIL this time round?"

Bottas is quick here and the track suits the Williams. But the biggest difference this year is the competitiveness of the Ferrari. It could be a good battle between those two teams this weekend, so I wouldn't rule out a repeat podium for the Finn.

Another question from Rohan: "Experts expecting Force Indias in top 10. Last year neither of them finished in top 10. What changes now?"

The Force India is a nicely sorted car this year - well balanced and with the advantage of the Mercedes engine. They have pushed on with development at the end of this year while rivals Lotus have a development freeze while they sort out their future. The Renault-powered teams will struggle a bit here so it's a perfect opportunity for Force India to score some good points.

Bottas remains fastest and is now out on super-soft tyres. He's 0.335s faster than Massa and 1.680 quicker than Raikkonen in third.

Bottas is slower in the first sector on the super-softs, but improves in the middle sector and improves overall to a 1:40.275.

Bottas extends his lead to 0.697 over team-mate Massa.

Siddhesh asks: "If Alonso is anyways going to start from the back of grid, why not take another new Engine and start with that? I understand saving a new Engine for later, but why introduce it now if they were never going to run it?!"

The simple answer is there is only one new engine in existence! Honda could only produce one and they have taken the penalty here in the hope that they will have a better race in Austin and can make use of the extra power there without the grid penalty.

Rosberg resumes business as usual with a 1:38.941 on the super-soft. Bottas improves but is 0.346s off.

The low temperatures and smooth track surface means the tyres are taking a few laps to be at their best. We saw the same here last year, but that is quite surprising given we have softer tyres here this year.

Rosberg is going faster again on his second flying lap on the super-softs. He did one cool down lap to condition the tyres and re-charge the ERS and now he is going again.

Lewis Hamilton is also out on the super-softs but has a huge lock-up into Turn 2 (which is the first big braking point here).

That ruins Hamilton's flying lap and won't have done his front-right tyre any favours either.

I can see a flatspot on Hamilton's tyre as he goes for his second lap. This time he negotiates Turn 2 with a little more caution and kisses the apex.

There is a car buried deep in the barriers. The TV screens say it is Carlos Sainz, but we can't see from the pictures.

It's Turn 13 and he has gone deep into the barriers. It's Tec-Pro barriers there and the car has made a big impact in them.

The medical car arrives on the scene. It looks like he went in at full speed on one of the fastest points of the circuit.

It looks like there is a scuff mark on the wall ahead of the braking zone, so he may have hit the barrier at high speed and then lost control and gone straight on.

The car lost power so the radio was not working when Toro Rosso tried to get in touch with him.

The marshals and medical crew are working to get him out from under the barriers, but we have no more information than that at this stage.

The cockpit was buried under the barriers when we saw an overhead shot. Concerned faces up and down the pit lane as Toro Rosso waits for news on Sainz.

Sainz had set his two fastest sectors of the session up to that point, so he was on a quick lap. We still haven't seen a replay, so we can't tell you exactly what happened.

The session will not be restarted. We are still waiting for news on Sainz.

We'll bring you an update here as soon as we know some news for certain.

Sainz has been put into an ambulance and appeared to wave from the stretcher.

A replay shows he lost the rear of the car in the kink ahead of Turn 13, hit the inside barrier hard breaking the suspension and then continued into the barriers beyond the run-off zone head on.

That accident brought a premature end to the final practice session. We'll bring more information when we have it and will be back for live commentary of qualifying.

One last message here, the FIA has confirmed Sainz was conscious and he did indeed give a thumbs up from the stretcher. Good news after such a big impact.