Welcome to live text commentary of the second free practice session at the Abu Dhabi Grand Prix's Yas Marina Circuit.

Sebastian Vettel tops the timesheets in the second session of free practice at the Abu Dhabi Grand Prix with a time of 1:41.751, and Lewis Hamilton and Jenson Button complete the three fastest. Mark Webber was fourth quickest, but the fuel loads make it all very difficult to assess. Still, Red Bull are very happy with Vettel's time.

We don't know the fuel loads, of course, which renders the times very difficult to gauge, but Alonso is pushing hard, while Hamilton and Button are both on good laps.

Alonso is relatively quick in his Ferrari, and is almost two seconds faster than Hamilton's last lap with the McLaren back out from his reluctant stop.

Vettel, Alonso and Button remain on track on their long runs, while Massa and Button are improving steadily.

Hamilton now complains of a gearbox issue, and he's having problems as he returns to the pits.

As Webber left the pits on this latest lap some water dripped from the underside of his car, and it has been an eventful and troublesome session for him.

Raikkonen is 0.781s off Vettel, whose time of 1:41.751 sees him continue to top the timesheets.

Alonso locks up through turn eight and has to protect his tyres as he comes through the chicane, while Raikkonen sets a new personal best to go sixth fastest.

A Tweet from Renault Sport: "Completely dark now, temps are a lot cooler now so the engine has to respond to this new set of parameters"

All the drivers are now on their soft tyres, and most teams are attempting to get to grips with what they would be doing if this were the race.

The yellow flag makes a fleeting appearance as Karthikeyan spins at turn 17, and that's a corner which many drivers have had trouble with.

Webber's car has some tape on its splitter now, and his Red Bull is having to be patched up frequently today.

Vettel remains fastest and has now gone back out on track after a brief stint in the pits with none of his rivals able to usurp him as things stand.

Petrov spins off the track as he exits turn 11, and there is no damage done, except to halt a promising lap.

Webber's car continues to have a lot of work done to it, and the Red Bull mechanics are working very hard on it.

Kobayashi has terrible understeer through turn one on the softs, and Senna goes the same way as both struggle.

Hamilton loses time in the final sector and is unable to pip Vettel - he's now 0.168s off the Red Bull.

While Button is in the pits after having only completed one lap on the soft tyres, while Hamilton finds extra pace in sector two as he keeps pushing.

Perez is really struggling to control his Sauber right now, while Alonso moves fifth quickest - he's 0.750s off Vettel.

Vettel now goes fastest with a 1:42.052, and he finds that crucial extra time to shave off, while Button returns to the pits.