Brazil confirms talks with U.S. Air Force to use KC-390 Millennium as a new complementary tanker.

Brazil’s Embraer CEO confirmed that it is in discussions with the U.S Air Force to propose the KC-390 Millennium as a complementary tanker aircraft, in a context where U.S. tanker demand continues to exceed available capacity across multiple theaters.

The proposal focuses on integrating the KC-390 Millennium into U.S. tanker operations to support shorter-range missions and relieve overstretched fleets such as the KC-135 and KC-46, amid high operational tempo driven by Middle East deployments. This approach strengthens battlefield fuel distribution efficiency and aligns with emerging concepts like Agile Combat Employment, improving readiness, survivability, and distributed airpower projection.

Read also: U.S. and Brazil Companies Launch KC-390 Autonomous Boom Tanker Bid for U.S. Air Force

With a maximum takeoff weight of 87,000 kg, the KC-390 imposes lower runway load and pavement classification requirements, enabling operations from shorter and less reinforced airfields that are inaccessible or restrictive for heavy tankers. (Picture source: Brazilian Air Force)

On March 28, 2026, the CEO of the Brazilian company Embraer, Francisco Gomes Neto, confirmed that it is in discussions with the U.S Air Force to propose the KC-390 Millennium as a complementary tanker aircraft, in a context where U.S. tanker demand continues to exceed available capacity across multiple theaters. The proposal initially emphasizes refueling missions rather than transport, as heavy tankers are currently used below optimal capacity in existing operations. The timing is linked to increased defense spending and short-term operational requirements driven by ongoing conflicts, particularly in the Middle East. Current tanker usage rates remain high, with aircraft tasked for long-duration missions and repeated deployments, which increases maintenance cycles and reduces availability margins.

The initiative introduces the possibility of inserting a medium-capacity aircraft into a fleet that currently operates with a binary structure between heavy and light refuelers. This structural gap affects how efficiently fuel is delivered at the tactical level for missions that do not require maximum fuel offload. The KC-390 is positioned to address this gap without altering the strategic tanker backbone, which remains centered on U.S.-made aircraft. The U.S tanker fleet is currently composed primarily of the heavy Boeing KC-135 Stratotanker and the Boeing KC-46 Pegasus, with a total inventory estimated between 460 and 500 aircraft across active and reserve components.

The KC-135 fleet accounts for the majority of this total (around 70 to 80%), with aircraft that entered service in the late 1950s and now exceed 60 years of age. The KC-46, with a fuel capacity of about 96,000 kg, is being introduced to replace part of this fleet but remains below planned totals, even after 100 deliveries. Both aircraft are designed for high-capacity fuel transfer, capable of delivering over 90,000 pounds (40,800 kg) of fuel per sortie at operational radius. They support missions such as bomber task forces, intercontinental fighter deployments, and continuous refueling tracks lasting up to 12 hours.

Their operational requirements include long paved runways and established airbases, limiting deployment flexibility. High sortie rates and global commitments continue to stretch these assets. This structure leaves no aircraft optimized for medium-capacity refueling missions. The KC-390 operates in a lower weight and capacity category, with a maximum takeoff weight of about 87 tons compared to 188 tons for the KC-46 and 146 tons for the KC-135. Its internal fuel capacity is about 35,000 kg, with practical offload at tactical radius estimated between 40,000 and 50,000 pounds (18,000 to 23,000 kg), which is about half of what a KC-46 can deliver under similar conditions.

The Brazilian aircraft uses two turbofan engines, reducing maintenance complexity compared to the four-engine KC-135. It can carry up to 26,000 kg of cargo, allowing simultaneous transport and refueling missions. The rear ramp enables loading of vehicles, pallets, or personnel without specialized infrastructure. The aircraft is designed to operate from shorter runways and semi-prepared surfaces, expanding the number of usable airfields. This capability allows it to deploy closer to operational areas than heavy tankers, especially in theaters like the Indo-Pacific. However, the airframe's design introduces a trade-off between fuel and payload, as both cannot be maximized simultaneously.

Within the global tanker fleet structure, the KC-390 occupies a segment that currently does not exist in the U.S. inventory, with fuel capacity in the 30 to 50 ton range. Heavy tankers operate above 90 tons of fuel, while lighter refuelers such as MC-130 variants operate below 30 tons, leaving a gap in between. The KC-390 is capable of supporting small formations of 2 to 6 fighter jets, rather than large strike packages or bomber formations. It can also receive fuel from larger tankers and redistribute it forward, creating a relay chain that extends operational reach. This enables a redistribution of fuel within a theater rather than direct long-range projection. The aircraft can operate from austere airfields, reducing reliance on major bases.

This expands the number of refueling locations available to combat aircraft. The result is a more granular distribution of fuel across the operational area. Therefore, the KC-390 aligns with the U.S. Agile Combat Employment concept, which emphasizes dispersing aircraft across multiple smaller locations to reduce vulnerability. In this model, large tankers such as the KC-46 remain at safer distances, acting as fuel hubs, while smaller aircraft distribute fuel closer to combat zones. The KC-390 can operate within this framework by conducting shorter missions between forward locations and main tanker nodes. This allows fuel to be delivered in stages rather than through a single long-range sortie. It also enables fighters to take off with reduced fuel loads and receive fuel shortly after departure, increasing payload capacity for weapons.

The Embraer KC-390 Millennium would complement the Boeing KC-46 Pegasus and Boeing KC-135 Stratotanker by handling lower-volume, short-range, and forward-deployed refueling missions, thereby reducing inefficient use and operational strain on high-capacity strategic tankers. (Picture source: Army Recognition)

The model reduces dependence on fixed refueling tracks and large airbases. It also increases the number of operational nodes, complicating targeting for adversaries. This approach reflects a shift from centralized to distributed refueling operations. The limitations of the KC-390 are directly linked to its smaller size and refueling system. Its fuel capacity is about one-third that of a KC-46, requiring more sorties to deliver the same total fuel. The aircraft currently uses probe-and-drogue refueling, with transfer rates near 400 gallons per minute, compared to higher rates for boom systems used by most U.S aircraft. A boom-equipped version is under development with Northrop Grumman to address compatibility with receivers such as F-15, F-16, and B-52 aircraft.

The KC-390’s endurance is shorter, limiting its ability to sustain long-duration refueling missions. It is not suitable for refueling large receivers such as heavy bombers or transport aircraft at high rates. The payload and fuel trade-off also constrains mission planning. As expected, these factors restrict its use to secondary missions and routine refueling tasks, preserving KC-135s and KC-46s for strategic roles. However, the introduction of a medium-capacity tanker such as the KC-390 would shift the US Air Force's tanker fleet from a two-tier structure to a three-tier model, consisting of heavy, medium, and light refueling aircraft.

This would allow missions to be allocated based on fuel requirement rather than the availability of large tankers. Heavy aircraft such as the KC-46 would focus on long-range and high-volume missions, while medium aircraft would handle theater-level distribution. This reduces inefficient use of large tankers for low-demand missions. It also lowers the operational burden on aging KC-135 aircraft by reducing sortie requirements. The total fuel capacity of the fleet would remain unchanged, but its distribution would become more efficient. This structure increases flexibility and supports dispersed operations in contested environments. The KC-390 proposal is therefore centered on reallocating existing capacity rather than expanding it.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.