Monaco GP practice: Haas drivers issued rare black flag order

The rarely-used flagged message is often associated with a possible disqualification but Haas maintains that the FIA stepped in after a communications failure with the drivers.

Haas' Romain Grosjean during practice

Haas drivers Romain Grosjean and Kevin Magnussen were both shown a black flag after 20 minutes of Thursday's opening free practice at the Monaco Grand Prix.

The two returned immediately to the pits obeying the rarely-used flagged message which is one of the most serious and often associated with a possible disqualification.

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However, Haas explained that it was less alarming than feared and said that the sport's ruling body, the International Motoring Federation (FIA), had acted on their behalf after the team suffered a communications failure.

In a message, Haas said: “Telemetry and radio issue.... We cannot communicate with drivers. FIA stepped in so we could get cars back to the pits as the pit boards weren't doing the business.”