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Lewis Hamilton and Charles Leclerc’s disqualification, explained

Looking at post-race checks, technical regulations, and more

F1 Grand Prix of Great Britain - Previews Photo by Dan Mullan/Getty Images

Formula 1 is rarely, if ever, without controversy.

Sunday’s United States Grand Prix offered just the latest example. The close of the race saw Lewis Hamilton cross the line in second place, seemingly notching another podium and a critical result for Mercedes in their fight with Ferrari for second place in the Constructors’ Championship. Speaking of Ferrari, Charles Leclerc came across in sixth place, which would have meant critical points for the Scuderia in that very fight.

But then, word was released that post-race checks on both Hamilton’s W14, and Leclerc’s SF-23, found that the “plank” on the floor of both vehicles was not in compliance with F1’s Technical Regulations. The matter was referred to race stewards, and representatives of both teams were asked to meet with race officials.

Then came the decision, both cars were found to be in non-compliance with the regulations, and both Hamilton and Leclerc were disqualified.

Given how the situation unfolded, we thought it would be worth a moment to dive into the disqualifications, looking at what the planks are, the regulation that was violated, and how post-race scrutineering works in F1.

What are planks?

F1 cars all contain planks, or “skid blocks,” on the floors of their car. This technical element was introduced as part of safety changes made in the sport in the wake of Ayrton Senna’s tragic death.

When the skid blocks were first introduced they were wooden, but now teams use a composite material.

The reason for these skid blocks? They serve a two-fold purpose. First, they work to protect the chassis from damage when the car’s floor touches the track surface at high rates of speed.

However, they also act as a safety gauge. First mandated in 1994, their purpose is to make sure cars are not running too low, or too close to the track surface. The closer the car is to the track surface, the faster the car works through corners. However, speed can be dangerous, and during the late 1980s and early 1990s when teams were running their cars as close as possible to the track surface, some fatal accidents occurred, culminating in the tragic deaths of both Senna and Roland Ratzenberger at the San Marino Grand Prix at Imola during the 1994 season:

In response, F1 mandated these planks as a gauge, to help determine if cars are running too low to the ground.

What was the Technical Regulation the teams violated?

As you might expect, F1 is a sport filled with rules and regulations. The 2023 F1 Technical Regulations is a document 183 pages long, that covers everything you can imagine, from dimensions to “geometrical planes” and everything in between.

Article 3.5.9 of the F1 Technical Regulations governs the “Plank Assembly.” Specifically, the section that both Hamilton and Leclerc were noted to have violated is Article 3.5.9(e), which reads as follows:

The thickness of the plank assembly measured normal to the lower surface must be 10mm ± 0.2mm and must be uniform when new. A minimum thickness of 9mm will be accepted due to wear, and conformity to this provision will be checked at the peripheries of the designated holes.

As you can see, the thickness of the plank is required to be 10 millimeters. F1’s regulations allow for one millimeter to be worn down over the course of a race weekend due to wear and tear. Anything more than that, and the car will have been deemed to be in violation of the Regulations.

You can also see that “conformity to the provision will be checked at the peripheries of the designated holes.” Each plank has four holes placed in specific locations, to allow for measurement of the plank. Measurements are only taken at these four specific locations, to determine conformity under this Regulation.

The brilliant F1 analyst Albert Fabrega highlighted those on Sunday evening:

How were the violations discovered?

Following the conclusion of the United States Grand Prix, FIA Technical Delegate Jo Bauer and his team began their standard post-race checks of the cars.

As part of the process, the team conducted a “physical plank and wear inspection” on four cars, including Hamilton’s W14 and Leclerc’s SF-23. The other two cars that were inspected? Max Verstappen’s and Lando Norris’s.

Noted in Bauer’s report to the race stewards was simply that Hamilton’s and Leclerc’s were “found to be not in compliance with Article 3.3.5(e):

This was just part of the pre- and post-race scrutineering conducted by Bauer and his team. As you can see from the Technical Delegate’s Report that was produced following the race, checks on the cars began before the start of the race.

For example, tests done ahead of the United States Grand Prix included:

  • Multiple “front floor deflection tests” on Verstappen, Leclerc, and Zhou Guanyu;
  • Engine oil samples on Hamilton and Kevin Magnussen;
  • Fuel samples from George Russell, Esteban Ocon, and Magnussen;
  • The starting tyre pressure of all cars, as well as the starting tyre temperature on 13 of the cars, was checked as well.

Following the race, all the cars that finished the race were weighed, and “aerodynamic component or bodywork areas” were checked on Yuki Tsunoda, Norris, and Sergio Pérez.

As noted at the end of the Technical Delegate’s Report, the only violations were the plank violations found on Hamilton and Leclerc.

This process has led to two follow-up questions. First, why isn’t every car inspected in this manner? One reason is simple: Time. These checks do take a period of time to complete, and on a weekend such as this one, with teams looking to head to Mexico for next weekend’s Mexico Grand Prix, time is of the essence. Teams are looking to get things completed before getting on the road.

Then there is the fact that random checks can serve as a deterrence. If the potential is there for a post-race inspection to turn up something like we saw with Hamilton and Leclerc, the incentive is there to adhere to the regulations.

The other question is why the violations did not trigger further checks on the two other cars, Russell’s W14 and Sainz’s SF-23. Again, these inspections are done at random, and there is currently no provision that would trigger a subsequent check on a second car if a first car for a given team is found to be in violation.

Why was the penalty disqualification?

Following meeting with both teams — more on that in a moment — the stewards issued their decisions. Having found that both cars were noncompliant with the Technical Regulations, they issued the “standard penalty.”


Violations of the Technical Regulations come with an automatic disqualification, and while teams can argue for leniency based on some sort of extremal factor that could not be avoided, these tend to be open-and-shut matters.

In fact, both teams conceded when meeting with race officials that the measurements are what they were, and while they pointed to potential reasons for the excessive wear — the F1 Sprint format, the bumpy nature of the surface at COTA — they further conceded that the rules are what they are.

“Turning to the race result and the disqualification, set-up choices on a sprint weekend are always a challenge with just one hour of free practice - and even more so at a bumpy circuit like COTA and running a new package,” said Mercedes Team Principal Toto Wolff in the team’s post-race media report. “In the end, all of that doesn’t matter; others got it right where we got it wrong and there’s no wiggle room in the rules. We need to take it on the chin, do the learning, and come back stronger next weekend.”

What do the disqualifications mean in the bigger picture?

There is, of course, something else to remember.

These two teams — Mercedes and Ferrari — are locked in a tight battle for second in the Constructors’ Championship.

Hamilton’s second-place finish, coupled with a seventh-place finish for Russell, had Mercedes set to leave Austin having extended their lead over Ferrari by four points. Their original P2 and P7 netted them 24 points, in contrast to the 20 points seemingly gained by Ferrari when Leclerc finished sixth, and Sainz fifth.

However, dropping both Hamilton and Leclerc out of the points saw Sainz promoted to P3, and Russell to P5. The result? 15 points for Ferrari on Sunday, with just 10 for Mercedes. When you factor in the results from the F1 Sprint on Saturday, Ferrari outscored Mercedes on the weekend, 24 to 18.

Ferrari now sits just 22 points behind Mercedes in that fight.

Which means there is a scenario where second place in this battle comes down to, after an entire season, a few millimeters.