Haas F1 team explains why winglets snapped off in US GP practice

Both Romain Grosjean and Esteban Gutierrez suffered issues at Austin on Friday, leaving Haas on the back foot going into its home weekend.

"We didn't do good today. We need to do better tomorrow because we had a few issues with some rear winglets breaking off," said Steiner.

"We lost too many parts. It happened three or four times, always the winglet, but we realise now what it is and we'll fix it for tomorrow."

Steiner said the breakages were being triggered by "the kerbs, along with the high downforce through the first sector, corners three, four and five.

"It seems like the vibration meant they broke off where they are bonded, so we need to make a mechanical fix and then a better part for the future."

The plethora of issues inevitably resulted in a loss of track time, leaving Grosjean and team-mate Esteban Gutierrez down in 18th and 20th, both over two seconds off the pace.

"We lost a lot of parts on the car, they are not holding up as they should," said Grosjean.

"Because of those missing parts I was a long way off the pace and I haven't learned too much, so we need to work hard overnight to work out why this was."

Gutierrez added: "What happened wasn't nice, it disturbed our programme a lot.

"It brings a lot of confusion on the car balance, presents different scenarios, but we have some information to try to put it together.

"It wasn't an easy day for the whole team, but we need to stick together and work hard tonight to try to make things better for tomorrow."

There was further embarrassment for Haas towards the end of practice one when both cars had to be pushed back into the garage from the end of the pitlane.

"One stalled [Gutierrez] and the other couldn't find reverse [Grosjean], so we pushed them both back in. Nothing dramatic," said Steiner.

"It was just a mapping issue on the engine side, so the first stalled, and the second one we did for safety reasons instead of Romain trying to engage a gear and breaking the box."

To add to those problems, there was also a general lack of overall performance from Haas.

"We know where to go, but the lack of stable running doesn't help to find performance and the set-up," said Steiner.

"That's the biggest problem we've got, so with the engineers and the limited amount of data we've got we need to find a solution for FP3."