Valtteri Bottas has no idea why the engine cover of his FW36 was torn during Friday's second practice for the British GP.
Putting in the laps at the Silverstone circuit on Friday afternoon, Bottas was forced to pit when the left side of his car's engine cover came loose.
When he pitted it appeared as if a hole had been blow in the engine cover which was ripped.
Asked if he knew why it happened, the Finn told ESPN: "No, just the bodywork came off, and that's it really. I don't know yet, we will have to see but it just came off."
Bottas' problem was not Williams' first of the day as the team lost both cars within the first 30 minutes of FP1.
While test driver Susie Wolff, who was using Bottas' car, suffered an engine failure, Felipe Massa crashed his, damaging all four corners.
And although Bottas admits there is a "lot of work" for the team to do come Saturday, he feels he made up for some of the lost track time during FP2.
"We missed some aero tests we had planned for the morning so it's a pity but the main thing we focused on in FP2 was the set-up work. The aero work we can do here in the test next week. One session pretty much lost for us but we can't change it so it's ok.
"[It was] not bad for just one session. Quite tricky conditions today, quite windy and it's not an easy place to set up the car.
"A lot of work to do for tomorrow, it looks like Ferrari and Red Bull are a bit closer than Austria, I think it's going to be really tight so anything that we can improve we can help. It's definitely a downforce track and we know we still have work to do in that area."