F1 grey areas explained: from compression ratio to DAS and electric power exploitation. A detailed look at Formula 1’s regulatory grey areas.

From the Mercedes engine to hybrid energy deployment, the new regulations have already highlighted several grey areas, but each case comes with its own specific context and implications.

The 2026 Formula 1 season has already delivered a number of technical controversies, which was widely expected given what has been described as the biggest regulatory revolution of the past thirty years. The particular exploitation of electric power during qualifying by Mercedes- and Red Bull-powered cars, first reported by The Race and now banned by the FIA, has added to the ongoing debate surrounding compression ratio regulations. Altogether, these situations have reignited discussions about regulatory grey areas, where the risk lies in treating fundamentally different cases as if they were identical.

The three types of cases

The most classic form of a regulatory grey area occurs when a rule is open to multiple interpretations, leading to innovative solutions that lawmakers had not originally anticipated. In such scenarios, the FIA has limited room for intervention, often being forced to acknowledge the legality of solutions that, technically, do not violate the written regulations. A perfect example is the double diffuser introduced by Brawn in 2009, as well as the Mercedes DAS system from 2020, which stemmed from a rule that did not explicitly state that the steering wheel could not control additional movements of the front wheels. The recent clampdown on the exploitation of electric power in qualifying also falls into this category, as it targeted a practice that complied with all prescribed procedures but was ultimately used for a purpose different from the one initially intended.

Very different, however, are disputes concerning regulations that involve the direct measurement of a parameter. In these cases, it is appropriate to speak of illegality, as there is a clearly defined maximum or minimum value for a physical quantity, provided that it can be measured under all conditions. The 2019 controversy surrounding the fuel flow sensor serves as a clear example, as it involved a method that bypassed real-time monitoring of fuel flow by exploiting the limitations of the sensor itself.

The third type of case, while it may appear similar to the previous one, differs due to a crucial premise. In certain situations, a limit is imposed on a physical quantity that varies depending on conditions and therefore cannot be measured at all times. This issue repeatedly emerges in discussions about wing flexibility, which the FIA can only properly assess during static checks in the garage. In these instances, it is the static test that serves as the reference point, effectively accepting that the car cannot be fully monitored while on track and that limits can only be enforced when the car is stationary.

The compression ratio case

The current debate surrounding Mercedes engines falls into this third category, as the compression ratio is extremely difficult to measure while the power unit is in operation. As the rules are currently written, the solution fully complies with the regulations, which specify that the compression ratio must be measured at ambient temperature. What remains unclear, however, is the process that led to the current situation.

It was only last October that the FIA introduced an addition to the regulations, specifying that the verification must take place under cold conditions. In reality, there had already been a document in place—still valid and not publicly accessible—that outlined the procedure for measuring compression ratio, but it is unknown whether it also specified a reference temperature. If it did not, this would represent an oversight on the part of the FIA, as it would mean the rule was ambiguous and therefore open to interpretation.

Further clarification arrived in October, followed by another update in December, which required each power unit manufacturer to establish its own measurement procedure in compliance with the guidelines of the previous document and then submit it for approval to the FIA’s technical department. This episode raises questions about what constitutes a reasonable notice period for such regulatory changes, a concern that also applies to the subsequent tightening of the rules. In June, a second test will be introduced, to be carried out at 130°C, but rival teams remain skeptical about whether this will have any meaningful impact.

The FIA’s challenge

All of this is unfolding in a season in which Nikolas Tombazis had promised a zero-tolerance approach towards teams exploiting grey areas without first consulting the FIA. However, in the case of the Mercedes engine compression ratio, the issue lies in the fact that the ambiguity did not concern only what was or was not allowed, but also the Federation’s own verification procedures. It serves as further proof that, no matter how much preparation is done, every technical controversy is unique, and it explains why the FIA often finds itself reacting to developments rather than staying ahead of the teams.