What is the issue?
The rules (Article 3.8 of the Technical Regulations specifically) dictate that all components influencing a car’s aerodynamic performance – such as front and rear wings – must be “rigidly secured to the entirely sprung part of the car” and “remain immobile in relation to the sprung part of the car”.
In other words, moveable (or flexible) aerodynamic devices are not allowed – save for the DRS – because in theory they can offer a performance gain.
To make sure parts are not flexing (or moving) under aerodynamic load, the FIA puts wings through load and deflection tests. If a part fails the test, it can’t be used.
However, the FIA “reserves the right to introduce further load/deflection tests on any part of the bodywork which appears to be (or is suspected of) moving whilst the car is in motion”. And earlier this month, without accusing anyone of breaking the rules, the FIA issued a technical directive stating that the load tests would be changing.
Lewis Hamilton said in Spain that “the Red Bulls are really fast on the straights. They have this bendy wing on the back of their car"
Why has it come up now?
Some teams believe that the rear wings on rival cars are flexing too much this season which could in theory provide a small performance advantage – with world champion Lewis Hamilton saying in Spain that “the Red Bulls are really fast on the straights. They have this bendy wing on the back of their car which they put on today and they gained at least three-tenths from this wing”.
In response to that, Red Bull boss Christian Horner said: “I saw the comment. Of course the car is scrutineered thoroughly and there's fallback tests, all kinds of different tests it has to pass.
READ MORE: FIA to introduce new tests on Formula 1 rear wings from June
After Hamilton's comments in Spain, Red Bull Christian Horner said the FIA were "completely happy" with the Red Bull car
“The FIA are completely happy with the car, that it's passed all of those tests that are pretty stringent so I was surprised to see his comments on that.
“But it's something that Toto [Wolff] has mentioned to me previously, so I doubt it was Lewis' opinion. It probably came from elsewhere.”
It’s worth noting from the outset that no team has failed a deflection test, but some teams – including Mercedes, who are locked in a tight title fight with Red Bull – are unhappy because they believe that such flex contravenes the rules.