The FIA is reportedly moving to revise the Formula 1 ADUO timeline after the Bahrain and Saudi Arabian Grands Prix were called off amid conflict in the Middle East.
This change has cut the 2026 calendar to 22 races and pushed a key engine review point deeper into the season.
Formula 1 confirmed the two April events will not be replaced, a decision it said was taken with the FIA and the race promoters, leaving a five-week gap between the Japanese Grand Prix on March 27-29 and the Miami Grand Prix on May 1-3.
That gap does more than thin out the spring schedule. It also disrupts the sport’s new Additional Development and Upgrade Opportunities system, known as ADUO, which the FIA created to help any engine maker that falls too far behind under the new power unit rules.
How the ADUO system works
The FIA brought in ADUO to prevent the new engine era from tilting too heavily toward a single supplier at the start. The sport had seen that happen before in 2014, when Mercedes built an edge that rivals struggled to erase for years.
With a clean-sheet power unit formula for 2026 and several manufacturers in the field, the FIA chose to build in a safety net. Under the system, the FIA tracks engine performance through the season and carries out formal reviews after Races 6, 12 and 18.
It does not judge this by lap time alone. Instead, it uses a performance index based on dyno figures and other measured data for the internal combustion engine. If a manufacturer sits more than 2% behind the benchmark after six races, it can gain one extra upgrade later that season and one more for 2027.
If the gap exceeds 4%, the allowance increases to two in-season upgrades and two more the following year. More than one supplier can qualify at the same time.
The rules also try to stop abuse. The FIA can remove ADUO privileges if it believes a manufacturer has held back on purpose to get help. The rules include a clause to deter sandbagging and to protect the system’s goal.
ADUO can also touch spending rules. If a supplier suffers major reliability trouble, the FIA can allow some budget cap relief. FIA technical director Nikolas Tombazis has said a full power unit costs about $1.5 million to $2 million, and ten failures could leave a manufacturer facing a $20 million hole under the strict cost cap.
How the cancellations disrupted the timeline
The trouble for the FIA is simple. ADUO runs on fixed points in the race calendar, and the calendar has changed.
What had been the sixth race check near Miami now lands much later because Miami has become only the fourth round after the Bahrain and Saudi Arabian events were removed.
As the rules now read, the first key review would slide to Monaco in early June. That would delay any extra development help by several weeks. In a season where rivals are already chasing Mercedes, that lost time could shape the title fight and the order among engine suppliers.
For Ferrari, Honda and Audi, an earlier ruling could open the door to faster recovery.
For Mercedes, any delay helps protect the lead it built at the start of the new rules cycle. That is why the timing of when the ADUO rules are applied matters.
Mercedes appears to set the baseline for the ADUO test because its power unit has looked strongest so far. Ferrari has shown strengths at the start and in the corners, but the gap on the straights has been hard to miss.
If Honda is more than 4% behind on the FIA’s index, as some paddock readings suggest, it would qualify for the larger package of extra homologation chances.
The issue has grown sharper because of claims that Mercedes may have held some performance back to keep rivals from crossing the ADUO threshold. Those claims remain claims, not proof. Still, they have added mistrust to a debate that was already tense.
The compression ratio controversy
A second technical row is running alongside the ADUO dispute.
From June 1, the FIA is due to measure the 16:1 compression ratio limit with engines both cold and hot. From the start of 2027, compliance will be judged only from the higher-temperature reference.
Mercedes has faced suspicion that it has found a way to run a much higher ratio. Rivals claimed it to be as high as 18:1 when the engine is at working temperature.
Mercedes says its power unit will pass the tougher June 1 checks and that it will not lose performance. Rival teams do not share that confidence.
Ferrari’s team principal, Fred Vasseur, has made clear he sees more promise in ADUO than in waiting for the compression-ratio checks. His view is that Ferrari’s engine shortfall could qualify it for help under the concession system. It will give the team a more direct chance to cut into Mercedes’ lead.
That helps explain why the FIA wants to act soon. Several reports say officials are looking at ways to move the first ADUO trigger back toward the original point in the season. This will be done either by fixing a date in the rules or by changing how the race-count marker works.
Because Mercedes may stand alone in opposing such a move, the proposal appears likely to gain enough backing when manufacturers discuss it.
Aston Martin has pushed hardest for a quick answer. Its Honda power unit is seen as one of the furthest from the benchmark. Chief trackside officer Mike Krack said the earlier any changes can be made, the better for his team.
What comes next for Formula 1
The next step is the meeting of technical chiefs after the Japanese Grand Prix, as reported by The Race. Officials are expected to review changes that could smooth out the new engine rules, with energy management likely to sit near the top of the agenda.
That meeting also gives the FIA a clear chance to reset the ADUO schedule. If it succeeds, the first review could return to something close to the original window. It would allow struggling suppliers precious time to react before the season’s midpoint.
If not, the current wording would leave Monaco as the first real opening for help.
The cancellations do not change the team budget cap. The rules already set the full $215 million allowance for seasons with 24 races or fewer. So the drop to 22 rounds does not reduce that figure.
The bigger question now is whether Formula 1 can stop a new rules cycle from favouring a single manufacturer. Formula 1 wanted ADUO as a guardrail against one engine maker running away with the field.
After the Bahrain and Saudi Arabian cancellations, the FIA must now decide whether the system can still do that job on time.
