The ADUO system has been one of the most controversial political and technical subjects in Formula 1 during the first half of the 2026 season, and the FIA now accepts that changes may be required. Nikolas Tombazis, the FIA’s Single-Seater Director, has defended the accuracy of the measurements used to determine which power unit manufacturers receive additional development opportunities, while acknowledging that the mechanism itself contains weaknesses that should be addressed in future seasons.
ADUO, or Additional Development and Upgrade Opportunities, was originally conceived as a safety net for manufacturers that found themselves significantly behind with the new generation of Formula 1 power units. The objective was to prevent a manufacturer from becoming trapped in a major performance deficit, avoiding a repeat of the difficulties experienced by Honda under the previous engine regulations. A detailed explanation of how Formula 1’s ADUO system allocates additional development opportunities shows why the mechanism has become so important to the 2026 technical battle.
However, what began as a protective measure quickly developed into a source of disagreement between the manufacturers. Concerns increased further when the FIA’s first ranking compiled after the Canadian Grand Prix unexpectedly identified the Red Bull Ford Powertrains internal combustion engine as the benchmark.
Why Formula 1’s ADUO system has become controversial
Two structural issues sit at the centre of the current debate. The first concerns what the FIA actually measures. ADUO performance assessments consider only the internal combustion engine, or ICE, even though the additional development opportunities available to manufacturers can also be used on the electrical side of the power unit.
This creates a potential discrepancy between the parameter used to determine eligibility and the areas in which development concessions can subsequently be applied. Nikolas Tombazis has previously explained why the current FIA ADUO assessment focuses on ICE performance, but the distinction remains one of the issues generating discussion between manufacturers.
The second controversy has centred on speculation within the paddock over whether some manufacturers could deliberately avoid displaying the full potential of their power units during the opening weekends of the season in order to secure additional development opportunities. Mercedes has been one of the manufacturers most frequently mentioned in those discussions.
Questions over Mercedes’ true power-unit performance have become particularly sensitive because of the way the ADUO rankings interact with development concessions. The issue has also been highlighted by the apparent paradox created by Mercedes’ power-unit strength and the ADUO mechanism.
The situation prompted Red Bull to request a factual verification of the measurements, delaying the official publication of data that had been expected after the Monaco Grand Prix.
Nikolas Tombazis defends FIA ADUO measurement accuracy
Speaking in an interview with British publication Autosport, Nikolas Tombazis addressed the dissatisfaction surrounding the implementation of ADUO and the difficulty of finding common ground between Formula 1’s teams and power unit manufacturers.
The former Ferrari engineer joked about just how difficult consensus can be in the sport.
“In Formula 1, it seems that almost everything is quite sensitive. It is really rare to find eleven teams and five or six Power Unit manufacturers saying, ‘Fantastic, we all agree.’ The only thing I think everyone agrees on is that the August summer break is a great thing, and I have to remind you that it was my idea. But that is the only thing everyone agrees on. Everything else is difficult.”
Nikolas Tombazis then drew an important distinction between the accuracy of the technical measurements themselves and the effectiveness of the overall system built around those measurements. On the first point, the FIA official remains confident that the governing body is obtaining reliable data.
“Everything is very delicate because everyone is extremely competitive and focused on their relative position compared with everyone else, so yes, it has been quite a challenge. I think our measurements have proved to be very accurate. That said, has everything worked perfectly? No, because obviously people are not happy. Do we need to think about improvements for the future? Yes, I would say so.”
Could manufacturers deliberately reduce engine performance?
Another theoretical weakness identified in the ADUO structure concerns the possibility of manufacturers deliberately limiting ICE performance in order to manipulate future development opportunities.
In theory, rival manufacturers could run below their maximum potential and leave another engine supplier at the top of the FIA ranking. That could potentially restrict the benchmark manufacturer’s access to additional development concessions while preserving more opportunities for those further behind.
Nikolas Tombazis, however, does not believe such an approach would make sense in practice.
“I don’t think it would be worthwhile always staying below maximum power just to continue having more opportunities, because at that point what would be the purpose of the opportunities if not ultimately to be ahead of everyone?”
The argument is that deliberately sacrificing current performance simply to obtain more development freedom would undermine the ultimate objective of those concessions: improving the power unit enough to become more competitive.
FIA considering ADUO changes for future F1 seasons
Even though Nikolas Tombazis rejected the idea that manufacturers are likely to pursue such an extreme strategy, the FIA has confirmed that it intends to review aspects of the regulations for future seasons.
The goal is not necessarily to abandon ADUO, but to simplify the process, reduce the administrative burden and limit the controversy created by the current methodology. For Ferrari, the mechanism remains particularly important because Maranello is continuing to use the available development opportunities as part of its 2026 power-unit programme.
The Scuderia has already identified further engine development as an important part of its attempt to reduce the gap to Mercedes. Ferrari is targeting the Italian Grand Prix at Monza for its crucial ADUO-2 development, while the team continues to work on improving the SF-26 during the second half of the championship.
That programme is particularly significant because Ferrari still considers Mercedes’ power-unit advantage one of the principal obstacles in its title challenge. Frédéric Vasseur has acknowledged that Ferrari remains behind Mercedes in power-unit performance, even though the Maranello team continues to believe it can fight for major results in 2026.
Nikolas Tombazis believes the basic concept behind ADUO is operating as intended, but he accepts that the system requires refinement.
“I think the system is working as it was designed, but I believe there are some weaknesses that we will have to address in the future. Also, to make it less time-consuming and less controversial, we need to take steps to improve it.”
His comments leave the door open to changes in the measurement criteria or wider operation of ADUO in future seasons. The FIA’s immediate challenge is therefore not simply to produce accurate power-unit data, but to ensure that the regulations built around those measurements provide development opportunities in a way that manufacturers consider both effective and fair.
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