Williams fear they could be ruled out of running on Friday entirely if George Russell needs a chassis change following his Azerbaijan Grand Prix first practice incident.
Russell ran over a loose drain cover ten minutes into the session which caused extensive damage to the bottom of his FW42, with the force lifting his front-wheels off the ground completely.
Although Russell reported he was unharmed, team principal Claire Williams fears they will need to build-up a third chassis.
"I just hit it and got the biggest smack through my body," Russell told Sky Sports.
"I was just going down the straight on my normal line. It's completely ruined our session, not ideal. I'm alright, tough guy."
Williams called the incident "unacceptable" and intends to take the matter up with race control.
"It's clear from the data that there's probably a lot of damage to the floor of the car," she added. "We'll have to wait and see if that chassis is repairable.
“The circuit needs to make sure that their drain covers are bolted down properly. That’s just not acceptable.
"The damage that that can do could put us out this afternoon. We have another chassis that we might need to bring in.
"That’s not what Formula 1 tracks should be. We'll be taking that up with race control."
The practice session was cancelled following the incident, with inspections of all 300 drain covers to take place before second practice.
