Lewis Hamilton continued to set the pace at the Circuit of the Americas but his Mercedes-AMG PETRONAS team-mate Nico Rosberg closed the gap and ended the second session on Friday only 0.003s adrift.
Unfortunately for Hamilton however, his session was cut short as his car developed a suspected hydraulic leak that saw it end the session up on the jacks with the mechanics looking beneath the car.
In a much windier session than the opening practice in the morning, Valterri Bottas was first on track as he tried to make up for lost time after missing out of the first session when his Williams Martini Racing team allowed test driver Felipe Nasr some time in the car, and he was quickly joined on track by the Lotus of Romain Grosjean (complete with his twin-tusk nose after running a Mercedes-style nose in FP1) and the McLaren Mercedes of Jenson Button.
Rosberg was the initial pacesetter when drivers ran the white-banded Pirelli Medium tyres, while Hamilton assumed top spot by the smallest margins when the faster yellow-banded Soft tyre runs began.
Fernando Alonso was third fastest for Scuderia Ferrari, and with team-mate Kimi Raikkonen sixth, it was a much more positive session for the Italian team, although Alonso was over a second slower than the pace of the Mercedes duo.
Daniel Ricciardo was fourth fastest for the Infiniti Red Bull Racing, but Sebastian Vettel joined the session late after a gearbox change, and did not attempt a qualifying simulation after the news he will start from the pit lane on Sunday following a power unit change.
Felipe Massa was fifth for Williams despite suffering a spin at turn one early in the session. Team-mate Bottas was just outside the top ten in eleventh, four tenths of a second slower than Massa.
Daniil Kvyat was seventh for Scuderia Toro Rosso as his impressive end of season form continued, finishing ahead of the two McLaren Mercedes drivers, with Kevin Magnussen just ahead of Button. Nico Hulkenberg completed the top ten for Sahara Force India.
Lower down the order, both Lotus drivers had spins during the session; Grosjean in the Esses early in the lap, while Pastor Maldonado spun exiting turn nineteen. They finished the session twelfth and fifteenth respectively.
Austin Free Practice 2 Times
|4||3||Daniel Ricciardo||Red Bull Racing-Renault||1:40.390||1.305|
|10||27||Nico Hulkenberg||Force India-Mercedes||1:40.800||1.715|
|14||11||Sergio Perez||Force India-Mercedes||1:41.123||2.038|
|18||1||Sebastian Vettel||Red Bull Racing-Renault||1:43.980||4.895|