In 1994, Formula 1 found itself in the rare position of trying to control the technologies of the future with a piece of wood.
By the early nineties, Formula 1 cars had become rolling laboratories where electronics did half the driver’s job. Active suspension adjusted the car’s ride height in real time for every corner, every bump, every speed range — squeezing the maximum possible downforce from the floor’s aerodynamics. Traction control stopped the wheels from spinning up on corner exits. ABS managed the braking. Launch control turned the start of a race from a test of nerve into the push of a button. Taken together, it meant the difference between a good driver and an average one was being erased: electronics smoothed out mistakes, compensated for a lack of feel, leveled the field. Alain Prost’s 1993 Williams FW15C — a car that dominated so emphatically with active suspension that it seemed to have arrived from another racing series — was the last straw.
The FIA, under its president Max Mosley, made a decision that resembled not a cosmetic revision but a reboot in its scope. For the 1994 season, all key electronic aids were banned at once: active suspension, traction control, ABS, launch control. The logic was twofold. First, restore the importance of driver skill — let the car once again demand that the person at the wheel know how to feel for grip, meter the throttle, brake on the edge of lock-up. Second, reduce speeds, because without electronic suspension correction the cars would lose some of their aerodynamic efficiency. But this created a problem the regulators foresaw: teams deprived of active suspension would immediately start compensating for the lost downforce by other means — above all, by lowering the car as close to the asphalt as possible.
To understand why a plank was needed, you need to recall for a moment how underfloor aerodynamics work. The air passing between a car’s flat floor and the track surface accelerates through the narrowing gap — and under Bernoulli’s principle, the pressure beneath the car drops. The pressure difference between the upper and lower surfaces creates downforce, pressing the car into the track without increasing drag. This is the very ground effect fully exploited by Lotus cars in the late seventies with their side skirts, before it was restricted by the flat-floor regulations in 1983.
The flat floor did not kill ground effect — it merely weakened it. And the closer that flat floor is to the asphalt, the stronger the effect. Every millimetre of ride height means specific kilograms of downforce and specific fractions of a second per lap. With active suspension, teams could keep the car extremely low on the straights, where speed was highest and aerodynamics mattered most, then raise it in braking zones and over kerbs so the floor would not strike the asphalt. Without active suspension — with ordinary springs and dampers — that trick was impossible: set the car low and it would scrape its floor over every bump. But Formula 1 engineers are the sort of people who take the word “impossible” as an invitation. They would start designing passive suspensions with minimal travel, stiff to the limit, just to keep the car millimetres from the asphalt.
The FIA needed a mechanism that would impose a physical limit on this race for ride height. Not a prohibition on paper that could be evaded through clever programming or interpretations of the rules, but something measurable, tangible, indisputable.
The solution was disarmingly simple. In the package of measures announced by the FIA on 13 May 1994 — just days after Imola — every car was required to carry a rectangular plank beneath the central section of its floor. The measures came in waves: aerodynamic restrictions at Barcelona, head protection and the removal of the airbox at Canada, and the full combination of “flat stepped floor plus plank” by mid-season, at the German Grand Prix in Hockenheim at the end of July. Width — 300 mm (with a tolerance of ±2 mm). Thickness — 10 mm (with a tolerance of ±0.2 mm). The plank had to be symmetrical about the car’s longitudinal axis and extend from a point 330 mm behind the front-wheel axle to the rear-wheel axle — 224 cm along almost the entire length of the floor.
The material chosen was Jabroc — a composite that sounds exotic but is astonishingly simple by nature. It is layered beech veneer impregnated with high-strength epoxy resin and compressed under pressure. A material used in industry for bearings, guides, wear-resistant surfaces. Its chief virtue for the FIA’s purposes is its consistent, predictable density and uniform wear. Jabroc does not crumble randomly, deform under heat, or delaminate under impact — it wears away evenly, in proportion to its contact with the surface. Crudely speaking, it is the perfect witness: it honestly records just how close the car was running to the track.
The operating principle is elementary. Before the race, the plank is measured. After the race — measured again. If at any point its thickness has been reduced by more than 1 mm from the original value, then the car was systematically running too low, extracting an illegal aerodynamic advantage. The car is disqualified. No sensors, no telemetry disputes, no questions about equipment calibration. A ruler, a micrometer, and a piece of wood.
What strikes me about this decision is its anti-elegance. In a sport where every component is designed to hundredths of a millimetre, where carbon fibre is laid up layer by layer in autoclaves, where aerodynamics are calculated in supercomputer clusters — the control instrument is a bit of wood. And it works.
The 1994 season was already tragic and scandal-ridden. The deaths of Ayrton Senna and Roland Ratzenberger at Imola in May. Suspicions that Benetton was using illegal traction control. The fire during Jos Verstappen’s pit stop at Hockenheim. Against that backdrop, the Belgian Grand Prix at Spa-Francorchamps was supposed to be just a race — but it became another episode in the war between Benetton and the FIA.
Michael Schumacher won the race. Won it convincingly, finishing first at a circuit he already considered one of his favourites. But the post-race technical inspection found that the plank beneath his Benetton B194 had worn down to 7.4 mm at certain points. Original thickness — 10 mm. Permitted wear — 1 mm. Actual wear — 2.6 mm at its worst points. This was not a borderline infringement, not a debatable tenth of a millimetre. The plank had lost more than a quarter of its thickness. The stewards disqualified Schumacher, and the victory went to Damon Hill in the Williams. One detail that adds bite to the episode: Spa was only the third race since the plank’s introduction — after Hockenheim and Hungary. The rule had barely had time to become routine, and the team had already been caught.
Here, it is important to separate fact from interpretation. Fact: the plank was thinner than the permitted limit. This was an objective measurement that Benetton did not contest. The argument concerned the reasons.
Benetton built its defence around three points. First: after the first pit stop, the car developed a “technical problem” — the team supported this with lap-time telemetry showing that Schumacher was slower after the stop than before it. Second, and most famously: on lap 19 of the race, Schumacher spun across the outside kerb in the Fagnes complex, and according to the team it was that kerb which scraped the plank down to the impermissible 7.4 mm. Third: teammate Jos Verstappen ran the same setup, and his car passed inspection — therefore, the setup was fine and something had simply gone wrong with Schumacher’s car.
The stewards took these arguments apart methodically, and this is where the episode becomes genuinely interesting — it was not some perfunctory dismissal but a real technical examination. Scoring from the kerb was indeed found, but on the rear section of the plank, while the problematic area was much farther forward. The stewards summoned the clerk of the course, who inspected the kerb and stated that it was too flat to inflict such damage; the kerb was searched, and “not a single piece of wood was found either on it or near it.” The FIA described the character of the wear itself as “very light,” with longitudinal scoring — meaning the plank had simply been rubbing against the asphalt in normal running, not torn open by an impact. The problematic area at the front indicated an excessively low nose. The stewards did not regard the argument about Verstappen’s car as proof: setups might match on paper, but different fuel loads and different histories of contact with the track produce different wear.
Benetton appealed, and a second line of defence emerged — a procedural one. The regulations contained a fallback mechanism: if the plank was thinner than the required 9 mm in some place, it could be weighed, and if it retained at least 90% of its original mass, everything was fine. The team insisted that this mechanism had to be applied. The stewards replied that the interpretation was wrong. The appeal was rejected, and the disqualification stood. Schumacher lost 10 points — the championship gap to Hill narrowed, and the title fight continued to the final round in Adelaide, where it ended in the infamous collision.
A curious detail nobody knew at the time: years later, Pat Symonds, one of Benetton’s leading technical minds, admitted that the team had in fact raised the ride height on the grid before the race — Schumacher had complained that the car was bottoming out on the reconnaissance laps. So an adjustment was made, but it was not enough. And that is perhaps the best illustration of all: even a team aware of the risk, an hour before the start, still chooses a compromise in favour of speed.
And yet there is no absolute here — there was one case in which an appeal succeeded. Indianapolis, 2001: Jarno Trulli in a Jordan was disqualified for plank wear, the team appealed, and the FIA’s International Court of Appeal in Paris upheld it within minutes. But not because the measurement was wrong — the measurement was perfectly sound. The reason was a procedural blunder: one of the three stewards was absent when the decision was handed down, while under Article 134 of the International Sporting Code, stewards must act as a collegial body under the chairmanship of their president. The disqualification was overturned, Trulli got his fourth place back, and Jordan recovered fifth place in the Constructors’ Championship. The conclusion is uncomfortable for any regulatory system: the plank does not lie, but the people measuring it can make a procedural mistake — and then a correct measurement collapses along with the decision.
To me, this episode reveals the very essence of the plank as a regulatory tool. A team can explain why the plank wore down. It can cite circumstances, mitigating factors, force majeure. But the plank is a binary judge. Either the thickness is within tolerance or it is not. There is no grey area, no space for legal casuistry about intentions and interpretations. Wood does not lie. The only way around it is to make people get the procedure wrong.
You might ask: surely teams with budgets in the hundreds of millions of dollars have found a way around a piece of beech? Attempts certainly have been made, and will be made. But the plank as a control instrument has a set of properties that make cheating extraordinarily risky.
First, it is physically the lowest point of the floor. Any attempt to protect it from wear — by applying a harder coating, for instance — is immediately discovered during inspection, because the regulations strictly define the material and the FIA specifies its characteristics: density, thickness, geometry. Second, the plank cannot be “swapped” between the finish and technical inspection — it is an integral part of the floor, mounted in a prescribed manner, and the inspection procedure begins in parc fermé immediately after the race.
There is a subtler aspect, too. Teams naturally set the car up to get as close as possible to the wear limit — that is part of the engineering game. But the risk here is asymmetrical: the gain from one extra millimetre of ride height is between 0.025 and 0.075 seconds per lap, while the loss from disqualification is every point from the race. The plank creates an economy of restraint in which a rational player will prefer to leave a margin.
One caveat, without which the picture would be incomplete: the plank can still be protected, and that was officially permitted rather quickly. From the 1994 Japanese Grand Prix onward — a month after Spa — teams were allowed to fit ten titanium skids to the floor: they took the impacts themselves and spared the wood. In 2015, titanium returned for spectacle, too — the shower of sparks from beneath the floor became part of the television picture. But the skids merely redistribute wear; they do not eliminate it: protected points wear more slowly, while the inspection holes and permitted millimetre remain. And right there lies the root of the story of the “satellite” skids of 2023–2024.
The plank survived every subsequent regulatory revolution. The switch from V10 engines to V8s, then to hybrid V6 turbos. The return and renewed ban of traction control. The introduction of the DRS system. The radical 2022 aerodynamic reform, which brought back full ground effect with shaped floors and Venturi tunnels — the very concept the plank had been intended to limit. The material evolved over time: alongside Jabroc, the regulations began allowing Permaglass — a fibreglass-based composite with similar uniform-wear properties. But the principle remained unchanged: a piece of material with known characteristics, measured before and after.
In the era of the 2022 cars and beyond, when ground effect again became the principal source of downforce, the plank acquired even greater importance than it had in the nineties. The phenomenon of porpoising — the vertical bouncing of cars at high speed caused by aerodynamic flow stalling beneath the floor — is directly connected to ride height: teams that wanted to run lower gained more downforce, but risked both their drivers’ health from the pounding and plank wear. Wear is measured at four inspection points — one at the front, one at the rear, and two at the sides in the middle of the floor — and protective skids may be fitted around them. In 2023, a technical directive allowed teams to attach so-called “satellite” skids across the entire floor area, provided they had the same vertical stiffness as the main ones: they took the impacts and protected the inspection points.
Then came Austin, October 2023. Lewis Hamilton finished second, Charles Leclerc sixth, and both were disqualified after inspection: their planks had worn beyond the limit. The first case in 29 years — exactly since Schumacher lost his victory at Spa. And at the 2024 Brazilian Grand Prix, the FIA closed the satellite-skid loophole as well: Red Bull and Ferrari had to urgently redesign their floor protection, followed by admissions from Mercedes and Alpine. Estimates of the loss ranged from 0.025 to 0.075 seconds per lap for every millimetre of raised ride height. Thirty years later, the arithmetic is still the same: millimetres against seconds, wood against engineers.
There is one detail I like: over the thirty years of the plank’s existence, Formula 1 technology has gone through several complete cycles — from the ban on electronics to their partial return, from flat floors to tunnels, from naturally aspirated engines to hybrids. But the bit of wood beneath the floor has remained. It has not become smarter, grown sensors, or turned into a digital instrument. It still rubs against the asphalt and still tells the truth — exactly the truth that can be measured with a micrometer in parc fermé after the finish.