Ferrari's Fernando Alonso put any nagging concerns about his back well and truly behind him as he topped the timesheets in Friday morning practice at the Circuit of the Americas.
However, the real winner was the weather which flexed its muscles and caused a 40 minute delay to the start of the session after a dense patch of fog rolled into the area.
The fog had marooned the mandatory medical helicopter away from the facility. Even once the fog cleared and the track went green, there was just 14 minutes of activity before the red flags came out for a second time when it was realised that the 'copter was not back where it was required to be outside the facility's medical centre.
By the time that the helicopter had at last been retrieved and restored to its designated launch position, there was only enough time remaining to allow a further 32 minutes of practice - meaning that the session had effectively been halved in duration as a result of the 'copter confusion.
In that short initial burst of track availability, McLaren leapt into action with Jenson Button topping the timesheets with a lap of 1:39.493s, 0.179s ahead of his team mate Sergio Perez. Only three other drivers succeeded in setting representative times before the stoppage, with Nico Hulkenberg in third place for Sauber ahead of Caterham's test and reserve driver Alexander Rossi who was the first American out on the track at a US GP weekend since Scott Speed in 2007. Rossi's team mate Charles Pic also set an early time, while everyone else with the exception of the Force Indias of Adrian Sutil and Paul di Resta had at least completed an installation lap before the new, lengthy stoppage.
Once the track reopened, all 22 cars were quickly into action to make up for lost time. It was Fernando Alonso who went top with a new benchmark of 1:38.767s which he then quickly lowered again to 1:38.343s on his next try, as times quickly tumbled as a result of the increasing amount of Pirelli rubber being laid down at the same time that the sand and dust was being cleared off the racing line with each new flying lap banked by the drivers.
With Jenson Button improving to within 0.028s of Alonso's time and Williams' Valtteri Bottas less than two hundredths of a second further back putting him just ahead of Esteban Gutierrez in the Sauber, it was certainly not the top four that anyone had been expecting. Drivers hopeful of setting even better times in the final minutes of the truncated session were thwarted by yellow flags out at turn 13 where the Rodolfo Gonzales' Marussia had pulled over onto the run-off, smoking its way gently into a stupor.
In the topsy-turvey session for which team test programmes had been thrown into disarray from the very start, it was difficult to directly compare performances. The two Mercedes drivers had a solid morning with Nico Rosberg finishing in fifth place just ahead of his team mate Lewis Hamilton, who was assured by the team pit wall that correcting for fuel load meant he was matching Alonso's pace.
Finishing the session in eighth just behind the second Ferrari of Felipe Massa, Mark Webber spent a large portion of the time engrossed in deep conversations with his race engineer about brake temperatures, but he was still faster than Sauber's Nico Hulkenberg and Williams' Pastor Maldonado who rounded out the top ten by the end of the truncated practice period
Webber was well in front of his Red Bull team mate Sebastian Vettel, who was left languishing in 18th spot six tenths slower than Daniil Kvyat whose first taste of F1 in Jean Eric Vergne's Toro Rosso saw the Russian youngster keep his nose clean in a careful outing ending with a best laptime of 1:40.065s, putting him six tenths ahead of the multiple world champion.
Among the other new faces in action for the day, Heikki Kovalainen débuted in the Lotus in 13th place, just two spots and a quarter of a second off the pace of his new team mate Romain Grosjean, while Alexander Rossi was the fastest of the four backmarker drivers with a time of 1:41.399s putting him just ahead of both Marussias and his own team mate Charles Pic.
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