Ahead of today's second free practice session, the air temperature is 31 degrees C and the track temperature is 44 degrees. It is still bright and sunny but with a fair amount of cloud.

The Red Bulls dominated this morning, though Sebastian Vettel out-paced his Australian teammate by almost half-a-second. The only driver anywhere near the Milton Keynes duo was Lewis Hamilton, the Englishman finishing the session 0.517s down on the German.

While Ferrari followed its usual plan, concentrating on reliability as opposed to pace, Fernando Alonso suffered an engine failure late in the session though the team had already revealed it was to be changed during the lunch break.

Petrov and Kobayashi both went off into the barriers at Turn 7, the Russian, in particular, doing quite a bit of damage to his car.

Christian Klien is first out once the lights go green, the Austrian replacing Sakon Yamamoto this weekend. Soon after he is joined by di Grassi - whose car was driven by Jerome d'Ambrosio this morning - Kobayashi, Webber, Vettel, Alonso, Glock and Kovalainen.

As di Grassi gives a running commentary over the course of his first lap of his home track, Klien posts the first time of the day, crossing the line at 1:19.887. Moments later Kobayashi posts 19.548 only for Klien to improve with an 18.504.

Just five minutes into the session and there are nine names on the timesheet, Heidfeld topping the lot with a 14.367. Meanwhile, Hamilton overtakes Liuzzi in the pitlane.

Kobayashi runs wide at Turn 7, the very same corner where he went off this morning. He and his teammate were separated by just four-thousandths of a second this morning.

Kubica goes quickest in sectors one and three, crossing the line at 14.441 to go third behind Heidfeld and Hulkenberg. Moments later however, a 13.603 sees Hamilton go straight to the top of the timesheet.

Button, who posts 13.899 to go second, complains of "very low rear grip". Moments later the McLaren duo are split by Schumacher who stops the clock at 13.818.

Fifteen minutes into the session all but Petrov and the Red Bull and Ferrari duos have posted times. In the Renault garage the crew is working furiously on the Russian's car - in every sense of the word.

As Alonso begins his first flying lap, teammate Massa posts 13.840 to go fifth. Moments later the world championship leader crosses the line at 14.182 to go ninth.

Next time around Massa improves to second with a 13.466 only to be demoted when his teammate crosses the line at 13.457. However, on his first flying lap, Webber posts 12.923 to go straight to the top of the table ahead of Hamilton who posts 13.048.

Webber ups the ante with a 12.839 as Petrov finally leaves the pits. As Vettel posts 13.342 to go fourth, Webber responds with a 12.569.

Vettel improves with a 12.854 but Webber isn't finished, the Australian digs deep to produce a 12.387.

Having closed to within 0.284s of his teammate with a 12.671, Vettel posts a 12.578 next time around to close to within 0.191s. Elsewhere, Petrov gets out of shape in the first turn.

On the half-hour, Hamilton posts 12.940, closing to within 0.553s of Webber, the top five - Webber, Vettel, Hamilton, Massa and Alonso - covered by just over a second.

Button posts a 13.366 to bump Alonso down to sixth, as Webber heads down the pitlane.

The usual suspects fill the bottom six positions with Glock the quickest of the newbies. In addition to Petrov, they have Toro Rosso and Force Indias for company. Rosberg posts 13.765 to go ninth, slotting in behind his Mercedes teammate.

Approaching half-time we've still not seen anyone on the option (super-soft) tyre, certainly not any of the big guns.

Webber goes quickest in S2 but fails to improve overall. Next time around the Australian dives into the pits.

At half-time, it's: Webber, Vettel, Hamilton, Massa, Button, Alonso, Kubica, Schumacher, Rosberg and Barrichello.

Massa and Schumacher are amongst a growing number of drivers to take trips across the Brazilian countryside, their tyres well past their best.