Friday practice started on a positive note, with both drivers refining the balance and evaluating a number of test items during FP1. After completing their initial runs in FP2, and finding further improvements, both drivers were forced to curtail their running just as they began their long-run simulations.
Fernando was forced to stop on-track after his engineers discovered anomalous data readings relating to his car's ERS water pressure. At the same time, Jenson's car encountered a separate issue - rising temperatures from his car's exhaust area. The team are still investigating the root causes of both problems. Neither driver was therefore able to complete their planned running in FP2.
Fernando Alonso: "We saw today that we seem to be a little bit more competitive here than at some of the previous races, and I believe there's a chance for us to make it into Q3 tomorrow.
"In the second session, I had to stop the car due to the fact that we saw an anomaly in ERS water pressure data. We're going to change the engine anyway for tomorrow, so this issue won't affect me at all for the rest of my weekend.
"With the high temperatures we had today, I think everyone suffered a lack of grip and degradation, but it looks like the weather is going to change, with some lower temperatures, cloud and rain. That would help us, as it would help reshuffle the deck a little.
"Tomorrow we need to have a good qualifying session - that's very important as overtaking around here can be quite difficult."
Jenson Button: "On low fuel, the car didn't feel too bad, it was relatively fun to drive. The balance still needs a bit of work on high fuel, but we didn't get much running done because we had an issue with the exhaust temperatures and had to stop. Neither car did much long-running today, which is a pity because we need that information, particularly for our understanding of the Option tyre's performance.
"Fortunately, the problem on my car should be very easy to solve; it's just hurt today's running. "Hopefully, we can get plenty of running in tomorrow - we need it. With the anticipated lower temperatures, qualifying should be fun - getting into Q3 will be tough, but that should be our aim. For the race itself, I'd like the weather to sort itself out and rain!"
Eric Boullier, Racing Director: "It was frustrating to see both cars stop in quick succession of each other, particularly as it meant that we weren't able to complete our proposed long-run plan at the end of FP2. Looking at it pragmatically, it's better that these issues occur during free practice rather than during qualifying or the race, and I'm sure we'll be able to quickly resolve the problems before tomorrow's sessions.
"In addition, with mixed and rainy conditions forecast for the remainder of the weekend, today's lack of running may not prove too consequential at the end of Sunday's race.
"On a more positive note, we were able to complete a fairly comprehensive test programme this morning, running through a number of correlation exercises and test-item evaluations, all of which should prove useful to our knowledge and understanding of next year's car.
"We'll have a little bit more work to do during FP3 tomorrow, but we've nonetheless made a positive start to the race weekend."
Yusuke Hasegawa, Honda R&D Co Ltd Head of F1 Project & Executive Chief Engineer: "Friday running at Interlagos started smoothly, with continued aero testing from the Mexican GP, which we were able to gather more data for future use. The sunny conditions at the track quickly raised the temperatures for the afternoon FP2 running, where we saw a drop in water pressure from Fernando's ERS so we elected to stop the car until we had further information.
"Engineers on Jenson's car detected a temperature rise in the gearbox and exhaust area, so we returned the car to the garage. Both instances are being investigated, but we believe neither should affect our running for tomorrow's FP3 and qualifying session."
Check out our Friday gallery from Interlagos, here.