F1: FIA changes tire check procedures after Massa's Brazil exclusion

The FIA has changed its procedures for measuring tire temperatures and pressures on the grid in the wake of Felipe Massa's exclusion in Brazil.

The move follows an internal investigation of Massa's tire issue by the team - the results of which were shared with the FIA by Williams' Pat Symonds.

One of the key issues for Williams was that no senior personnel were aware Massa's right rear tire had been checked on the grid by FIA technical delegate Jo Bauer and his assistant Kris de Groot, and the team knew nothing of any discrepancy until an official message came from the FIA after the race had started.

Now, any FIA tire check on the grid will have to be witnessed by the car's race engineer, who will then be made aware of any issues right away. This is similar to the way car weight checks are carried out, when team members can observe and log any figures.

This will also resolve another key issue – the anomaly that has allowed the FIA to record a car that is "unsafe" before the start, given the checks are in place at Pirelli's request, then allowing the car to start the race. This became a major talking point with Mercedes at Monza, as well as in the Massa case.

Now if the FIA records illegal numbers, the team will still have the option to take the car off the grid, change its tires, and start from the pit lane. The driver will start the race with a legal car, instead of wasting time by running under the threat of exclusion - although there could still be a penalty for the grid issue.

Meanwhile, the Williams investigation indicated the reading recorded by the FIA's infrared gun was affected by heat reflected by the tire blanket, and the logged figure of 137 degrees Celsius (278 degrees Fahrenheit) was not the true temperature of the tire itself.

Although the FIA has not officially accepted that as an explanation, it will adjust its tests in future by ensuring when the temperature is checked, the blankets are opened sufficiently so there is no risk of heat reflection having an impact.

Since the FIA is allowing a race engineer to look over the tire checks, it allows the team to make sure they are fully satisfied with the procedures.

Williams explored the phenomenon of heat reflection by using a thermal imaging camera on a tire in a blanket, which demonstrated what happened when the blanket was partially unwrapped. As the blanket was opened, the tire temperature dropped dramatically.

"What we're seeing is a heat reflection in exactly the same way that you get a light reflection," Symonds said. "That reflection is occurring where the tire is closest to the blanket - the reflection coming off the blanket. When you are well away from that heat source, you don't see the reflection, so therefore the reading is good."

Symonds also confirmed that had the team been properly informed on the grid about the tire potentially being overheated – as happened during the Russian Grand Prix weekend when a blanket issue effectively ruined a set - it would have reacted.

"Bare in mind this was a safety thing," Symonds said. "If they really felt the car was unsafe, they should have told us. If we had a tire blanket controller failure, like we had in Russia, we would have taken the car off the grid, because we would not have felt safe to start the race."