Haas duo in bizarre black-flag incident in Monaco practice

Less than 20 minutes into the start of FP1, the FIA showed black flags to both Haas drivers – which meant they had to return immediately to the pits.

Although there was no official explanation from the governing body about why the drivers had been summoned to the garage, it later emerged that the move came after the team lost contact with the duo.

With Haas having no way of telling its drivers that they were wanted back in the pits, after they failed to spot pit board messages, it approached the FIA for help.

A Haas spokesman said: "We can't communicate with drivers. The FIA stepped in so we could get cars back to pits as pit boards weren't doing the business."

Monaco's tall buildings and its famous tunnel make radio communication between the drivers and pits more difficult than at normal tracks which are more open.