U.S. Set to Approve $700M GE F110 Engines for Türkiye KAAN Fighter Testing Despite S-400 Dispute.

The United States is preparing to approve the sale of GE Aerospace F110 turbofan engines for Türkiye’s KAAN fighter, a deal reported at more than $700 million and designed to keep Ankara’s first fifth-generation combat aircraft moving toward expanded testing and early production. The decision would give Türkiye a critical path to propulsion for the program while keeping its progress dependent on U.S. export approval.

The engine package would support prototype development, accelerate flight testing, and enable production planning for a fighter intended to reduce Türkiye’s reliance on foreign combat aircraft. Congressional opposition tied to Ankara’s Russian S-400 air-defense system shows that KAAN’s development remains closely linked to wider U.S.-Turkish defense tensions ahead of the NATO summit in Ankara.

Related topic: Türkiye Advances NATO Amphibious Warfare Capabilities with M60TM Tanks and Indigenous Landing Craft at EFES 2026.

GE Aerospace F110 engines are central to Türkiye’s KAAN fighter program, providing the thrust needed for flight testing, weapons integration, and early production while Ankara continues work on an indigenous engine and manages U.S. congressional concerns over the S-400 dispute (Picture source: TUSAS).

The engine at issue is not a new or untested design. The F110 family already powers large numbers of F-16 and F-15 combat aircraft, and Türkiye operates F110-powered F-16s in one of the largest F-16 fleets outside the United States. The F110-GE-129 is in the 29,000 lb thrust class, with 270 lb/sec airflow, a 46.5-inch diameter, and a 0.76 bypass ratio; the higher-output F110-GE-132 is rated at 32,500 lb, with 275 lb/sec airflow and a 0.68 bypass ratio. For KAAN, Turkish Aerospace publishes a twin-engine thrust figure of 2 x 13,150 kgf, or roughly 2 x 29,000 lb, matching the F110-GE-129 class; against the aircraft’s stated 34,750 kg maximum takeoff weight, that gives a basic uninstalled thrust-to-weight reference of about 0.76 at maximum takeoff weight, before accounting for mission fuel, weapons load, drag, and installed-performance losses.

That matters because KAAN is still moving from demonstrator status into a more demanding test phase. Turkish Aerospace signed the KAAN development agreement with the Presidency of Defense Industries on August 5, 2016; the first prototype flew on February 21, 2024, for 13 minutes at 8,000 ft and 230 knots, followed by a second flight on May 6, 2024, lasting 14 minutes at 10,000 ft and 230 knots. Those flights validated basic airworthiness, not combat performance. The next stages require repeated expansion of the flight envelope, afterburner operation, supersonic testing, high-angle-of-attack evaluation, stores separation, radar cooling loads, electronic warfare operation, and flight-control refinement. None of that can be scheduled credibly without a stable engine supply, spare engines, test-cell support, and U.S.-licensed technical documentation.

The armament plan is equally dependent on the propulsion and test schedule. Turkish Aerospace lists internal weapon bays, within-visual-range and beyond-visual-range missile employment, precision strike, sensor fusion, an integrated radio-frequency system, an electro-optical system, advanced communications/navigation/identification, and a helmet-mounted display among KAAN’s stated features. Internal carriage is the critical point: a fifth-generation fighter loses much of its low-observable advantage when it must carry missiles or bombs externally. Internal bays allow KAAN to conduct the first phase of an air-to-air mission or a precision strike with lower radar exposure, then accept a larger radar signature only if external weapons are later required for payload or range.

The likely internal air-to-air package is being built around TÜBİTAK SAGE missiles rather than a permanent reliance on U.S. AIM-9X or AIM-120 stocks. Gökdoğan is the beyond-visual-range missile, with a 65+ km range, solid-fuel rocket propulsion, and an active radar seeker; Bozdoğan is the within-visual-range missile, with a 25+ km range, solid-propellant motor, and infrared seeker. Turkish reporting has also identified Gökhan, a ramjet-powered beyond-visual-range missile under development, as a future KAAN weapon for longer-range engagements. For strike missions, Roketsan’s SOM-J is the more relevant weapon: it is about 3.9 m long, weighs about 540 kg, has a 275 km range, carries a 140 kg high-explosive fragmentation or armor-piercing warhead, and uses INS/GPS, terrain-referenced navigation, image-based navigation, automatic target acquisition, an imaging infrared seeker, and data-link-enabled retargeting.

The tactical implication is that KAAN is being designed as more than an F-16 replacement with a national label. With Gökdoğan or Gökhan internally, it could support defensive counter-air missions by entering contested airspace with reduced signature, launching before an opponent can build a stable track, and then leaving the engagement area under sensor-fusion support. With SOM-J, it could attack air-defense nodes, command sites, naval targets, or hardened infrastructure from outside many short- and medium-range air-defense envelopes. The aircraft’s value will depend on whether Türkiye can integrate the radar, electronic warfare suite, data links, mission computer, and weapons into a single kill chain. Engines do not solve that software and integration problem, but without them, the problem cannot be tested at operationally relevant speeds, altitudes, and thermal loads.

Türkiye needs the engines because indigenous propulsion remains the longest pole in the KAAN program. Ankara can design airframes, radars, munitions, mission computers, and electronic warfare equipment, but a reliable afterburning turbofan in the 29,000 lb class is a different industrial challenge, involving turbine materials, hot-section durability, compressor efficiency, digital engine control, signature management, and thousands of hours of qualification. Using F110 engines allows Turkish Aerospace to keep aircraft development moving while a national engine matures. It also uses an ecosystem Türkiye already understands through the F-16 fleet, including maintenance practices, component production, depot experience, and pilot familiarity with F110 behavior in hot, high-tempo conditions.

The sale was pending not because of an engine problem, but because of U.S. export-control politics. The package is a direct commercial sale, meaning U.S. companies can sell defense equipment abroad only with U.S. government authorization. In practice, major sales normally pass through an informal congressional review before formal notification, and holds by senior members of the foreign affairs committees are often treated as politically important even when they are not always legally binding. Meeks’ objection centered on the S-400, but congressional aides also cited Syria, tensions with Greece, and Turkish military activity around Cyprus.

The S-400 issue explains why an engine sale became politically sensitive. The Pentagon said in July 2019 that Türkiye could not have both the Russian S-400 and the F-35 because the Russian system could collect intelligence on the F-35’s low-observable characteristics; Türkiye was then removed from the F-35 program, losing aircraft access and more than $9 billion in projected workshare. Congress later barred any return to the F-35 unless Türkiye no longer possesses the S-400 and commits not to acquire similar Russian systems. The F110 is not an F-35 engine, but Congress views any KAAN-related approval through the same trust deficit.

For Washington, approving F110 engines is therefore a limited concession rather than a full reset. It supports a NATO ally’s combat-aircraft continuity without transferring the most sensitive F-35 technology, and it keeps Türkiye partly dependent on U.S. licensing, sustainment, and spare-engine supply. For Ankara, the deal reduces near-term risk in KAAN but does not remove strategic vulnerability: if relations deteriorate again, propulsion could become a pressure point. The practical result is a compromise. KAAN receives the engines needed to continue development, Congress keeps the F-35 question separate, and the U.S.-Türkiye defense relationship remains functional but conditional.

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