When is a rule change not a rule change? Apparently it seems, when it is an "interpretation". Or perhaps, when the FIA feels the need to flex its political muscles.
It used to be that once the rule book was settled ahead of a new season, the rules stayed unchanged till the start of the next year. The FIA regulations; the fabled 'Yellow Book' states that the only time the FIA can change the rules without the agreement of all the teams, is if an issue directly affects safety. That was last invoked in 1994 after the deaths of Ayrton Senna and Roland Ratzenberger,
There was no safety issue in the past weeks. Yet the FIA invoked an "interpretation" covering exhaust blown diffusers; the blowing of gases through the exhaust pipe even if the throttle is closed, to boost airflow over the rear diffuser and enhance downforce.
At the European Grand Prix in Valencia, FIA Technical Delegate Charlie Whiting "interpreted" the use of the exhaust to influence the aerodynamic characteristics of the car as infringing regulations on driver controlled aerodynamics. At the British Grand Prix the FIA attempted to limit teams to 10 percent of the airflow in the cars' exhausts when the driver is off the accelerator.
This however, literally backfired. The teams pointed out different engines require different levels of 'blow by' in order to ensure reliability. The "interpretation" was then changed to allow Red Bull and the similarly powered Renault to keep 50 percent of the exhaust flow levels. That immediately led to complaints from the Mercedes-powered teams that they were being put at a disadvantage.
The whole affair spiraled into farce at Silverstone as the rules changed back and forth with a different "interpretation" for every practice session. Team Lotus driver Heikki Kovalainen summed up the drivers thoughts when he told me; "I've given up on the technicalities. All I do is when I get in the car, I ask my engineer do I have downforce in this session or not?"
Eventually after a race in which the Renault-powered teams claimed they were disadvantaged, the FIA backed down, proposing the field reverts to the blown diffuser throttle levels seen in the opening eight races of the season.
Steve Slater is an F1 commentator for ESPNStarSports.