Early optimism about the potential of the latest Williams F1 car was cast into doubt after it emerged that the Grove team would have to change the design of the FW35's exhaust.
The car was unveiled in the Circuit de Catalunya pit-lane shortly before the second group test of the 2013 pre-season got underway, and Pastor Maldonado – who won at the Spanish venue last year – posted the fifth fastest time of the day, but the FIA subsequently ruled that the team's exhaust contravened the rulebook and said that it would be banned.
While all teams have attempted to keep using exhaust gasses for some aerodynamic benefit since blown diffusers were outlawed at the end of 2011, both Caterham and, now, Williams have taken things a step further with their latest designs. Most 2013 cars channel the gasses towards the rear of the car, but the FW35's exhaust layout features a tiny slot at the top of the channel, and it is this that the governing body has reacted to.
The design is thought to contravene article 5.8.4 of the technical regulations, which states that the sides of the exhaust channel cannot meet. The Williams design would form a complete circle were it not for the slot.
Ironically, Williams' technical director Mike Coughlan began the day by insisting that, in his opinion, the FW35's exhaust fell within the rules, while Caterham's – which features a small turning vane within its exhaust channel – did not.
"For me, the Caterham one is clearly not allowed," Coughlan was quoted by ESPN
, "Ours is okay because, if you look, it's actually not a single piece; it's two pieces. The rule is an aperture size, and ours is an aperture size; ours is one aperture because it's joined by a small piece in the middle.
"You're governed by total aperture size, but singular aperture, and ours is a single aperture joined by a very small slot, so it's actually two pieces if you look closely."
The FIA, however, disagreed and reacted swiftly, outlawing both
the Williams and Caterham designs before the end of the day.
"The team spoke with the FIA this morning which is when they gave us their view," a Williams spokeswoman told journalists in Barcelona, "The team are now seeking further clarification on this and a decision as to whether this design will be carried forward will be made before the first race."
There is no threat to Williams' immediate programme, as the team can continue to run the exhaust in testing, but should the ban be confirmed after it presents its case to the FIA, it would need to come up with an alternative solution in time for the opening round of the championship, in Australia, over the weekend of 17 March. This would likely need to be done in time for the final four-day test, which also takes place in Barcelona, early next month.