Azerbaijan GP practice cancelled after manhole cover incident
First practice at the Azerbaijan Grand Prix was cancelled after George Russell's Williams was damaged on a loose manhole cover.
The Briton's car caught the edge of the cover between Turns Two and Three and it smashed the floor of his car, which then shut down.
The cover appeared to have been loosened by Charles Leclerc's Ferrari.
In farcical scenes, the truck bringing Russell's car back to the pits crashed into a bridge over the track.
That leaked hydraulic fluid on to Russell's car beneath.
Mercedes' Lewis Hamilton joked on social media: "How could they have not checked and sealed the drains? Oh well, just gives me extra time to catch up on Game of Thrones."
Race director Michael Masi soon cancelled the rest of the session, in which only the Ferraris had set lap times, to try to resolve the multiple problems.
Masi will have to not only make sure the damaged cover is repaired but also check the remaining covers around the track - and ensure that the bridge that was damaged is structurally sound.
There are thought to be 300 manhole covers around the circuit.
Russell said: "There was a manhole cover and I got the biggest smack on my body. The engine turned off."
Williams will need to change the chassis because of damage and so regulation dictates he will not be able to run again until Saturday's final practice.
Ferrari had gone out early with both cars to try out a major aerodynamic upgrade they have introduced for this weekend.
But Leclerc and Vettel were limited to just five and four laps which will give the team some data on the airflow around the car but only very limited information for the drivers in terms of how the new aerodynamics affect the balance of the car.
Mercedes drivers Lewis Hamilton and Valtteri Bottas, first and second in the championship after three consecutive one-twos at the start of the season, did not even go out for an installation lap.