[8] A modified version of the car dubbed the FW09B was introduced in Round 10 of the season at Brands Hatch for the 1984 British Grand Prix.

Rosberg was 8th at the Dutch Grand Prix while Laffite ended the season in Portugal with a disappointing 14th place, following which the FW09 was retired.

One particular incident that was more or less a summation of Williams's season was at the Austrian Grand Prix at the Österreichring – which was at the time the fastest circuit used by Formula One with average lap speeds as high as 150+ mph – Rosberg drove into the pits from 9th place and informed technical director Patrick Head that he was retiring the car from the race because it was dangerously unstable at the Österreichring's very fast sweepers and he feared he might have a massive accident – all too commonplace at such a fast circuit.

The Finnish driver, who had amazing reflexes and had a flat-out driving style was not one to just quit out of fear, and Head, a hard-nosed character with little patience for losing, accepted Rosberg's decision wholeheartedly.

Williams, which along with Ferrari and Brabham were one of the few race winners in a season dominated by McLaren drivers Niki Lauda and Alain Prost, finished sixth in the constructors' championship in 1984 having scored 25.5 points.