The FIA checks at centre of Ferrari's F1 Abu Dhabi GP controversy

Ferrari has been under scrutiny from rivals over its power unit in the wake of several technical directives.

There was then further intrigue in Abu Dhabi when the FIA found a "significant difference" between the fuel amount Ferrari had declared before the race and the amount found in the car.

The incident prompted more conspiracies and questions as to whether Ferrari had made a simple administrative error or not.

Ferrari was then fined €50,000 for the 4.88kg difference between its declaration and what the FIA found in the car.

How Ferrari fell foul of the rules

F1's fuel limit rules mean teams have to declare how much fuel they plan to put in the car for the race.

Furthermore, FIA technical boss Jo Bauer and his team have the right to weigh the cars before and after the race to determine exactly how much fuel has been used - and how that matches up with the fuel-flow meter's reading.

Ahead of the start of this season, TD12-19 was issued to all teams by F1's head of single-seater matters Nikolas Tombazis outlining how fuel measurements would be taken.

Teams have to declare the amount of fuel they intend to put in the car - an allowance which covers the laps to the grid, the formation lap, the race and the in-lap - before the pitlane opens.

This amount of fuel has to be in the car's tank 40 minutes before the race, after which time no fuel chilling will be allowed.

The FIA then reserves the right to randomly check cars before the race, and the car is weighed with a set of "travel wheels" marked by the FIA and with a known weight.

The team will then be asked to drain the fuel tank and the fuel pump is then run to ensure that all remaining fuel goes into the collector.

The FIA then makes sure that there is nothing left in the car.

The car will then be weighed again, and a fuel mass calculated from the difference with the earlier weight.

The fuel will then be pumped back into the car, which will then be weighed for a third time.

The fuel hatch and QD (quick disconnect) will then be sealed so no fuel can be added or removed.

Following the race, the FIA can again choose cars for random fuel checks after the usual parc ferme procedures have been carried out.

The car will be weighed with the same marked travel wheels used in previous checks.

As before, the team will be asked to pump out any remaining fuel, and the FIA will make sure that none remains in the car.

A further weight check will be used to determine that the mass of fuel has been used from the laps to the grid to the in-lap.

The car will then be weighed again.

In the aforementioned technical directive, Tombazis notes that "the difference between the pre- and post-race fuel masses will be assumed to be the measured fuel mass used (which clearly includes laps to the grid, formation laps, fire-ups etc).

"It can be compared to the integrated FFM [fuel flow meter] figures and to the fuel injectors model figures in order to provide confirmation of the validity of these readings.

"Please note that the pre-race fuel mass that gets used for this calculation is either the declared mass or the measured mass if this has been randomly checked."

Tombazis gave a very specific list of situations which may trigger further investigations and/or the team concerned being reported to the stewards.

It reads as follows:

1. If the fuel pump-out procedure differs from the declared and documented process, then the team is required to communicate to the FIA in advance.
2. If a significant volume of fuel is found in the car after the fuel has been pumped out using the above procedure.
3. If the team fails to make a fuel mass declaration more than two hours before the pitlane opens, or if the declared amount of fuel is significantly different to what gets drained in the event of a random check.
4. If the comparison between the integrated fuel flow meter signal and the measured fuel mass consumption shows the former to be lower than the latter.
5. If the fuel mass used for the race, assessed with the car weight comparison, exceeds 110kg, as required by Article 30.5 of the F1 Sporting Regulations.
6. If software inspections and/or data analysis show significant operational differences between qualifying and the race.

Ferrari fell foul of the first point in Abu Dhabi but there has yet to be an official explanation as to where the difference originated from.