TUSAS Subsidiaries and Partnerships: TEI, TCI and EUROTAI
The subsidiaries of TUSAS (Turkish Aerospace Inc.) are companies in which it holds equity, while its partnerships are industrial ties run at the licence, work-package or programme level without any shareholding. Its best-known affiliate is the engine maker TEI (TUSAS Engine Industries), in which it holds a majority stake. TCI covers cabin-interior systems and EUROTAI covers helicopter structural work as further affiliates and joint ventures. Alongside these, TUSAS runs work-package partnerships with Airbus, Boeing, Leonardo, Sikorsky and Lockheed Martin that carry no equity. Some ownership splits have not been officially disclosed in detail.
| TUSAS Subsidiaries and Partnerships — Summary | |
|---|---|
| What is a subsidiary? | A company in which TUSAS holds equity (e.g. TEI, TCI, EUROTAI) |
| What is a partnership? | A licence / work-package / programme tie (no equity required) |
| Flagship affiliate | TEI — TUSAS Engine Industries (TUSAS 50.5%, GE 46.2%) |
| Cabin systems | TCI — joint venture of Turkish Airlines, TUSAS and HAVELSAN (2010) |
| Helicopter structures | EUROTAI — joint venture with Airbus Helicopters (formerly Eurocopter) |
| Industrial partners | Airbus, Boeing, Leonardo, Sikorsky, Lockheed Martin, PTDI |
| Ecosystem (subsystems) | ASELSAN, HAVELSAN, ROKETSAN, TUBITAK SAGE (not affiliates) |
| TUSAS ownership | TSKGV 54.49% · SSB 45.45% · THK 0.06% |
| General Manager | Dr. Mehmet Demiroglu |
What are TUSAS subsidiaries and partnerships?
At TUSAS, a subsidiary and a partnership are two distinct things. A subsidiary is a company in which TUSAS directly holds shares; it has a stake in the company’s capital and takes part in its governance. A partnership is a broader concept that covers licence agreements, co-production, work packages or programme-level industrial cooperation carried out without any shareholding. The distinction matters, because TUSAS building parts for Airbus or Boeing is a work-package partnership, not a subsidiary relationship.
The main companies in which TUSAS holds equity are TEI (TUSAS Engine Industries) in engines, TCI (Turkish Cabin Interior) in cabin-interior systems, and EUROTAI in helicopter structural production. Beyond these, the company runs work-package and programme partnerships with the world’s large aerospace primes. TUSAS itself is not publicly traded; its own ownership is split between TSKGV at 54.49%, SSB at 45.45% and THK at 0.06%.
TEI: the TUSAS engine affiliate
The flagship TUSAS affiliate is the aero-engine maker TEI (TUSAS Engine Industries / TUSAS Motor Sanayii). Founded in 1985 as a joint venture and based in Eskisehir, its ownership is structured as follows:
- TUSAS (TAI): 50.5% — TUSAS holds the majority stake.
- General Electric (GE Aerospace): 46.2%
- TSKGV and THK: 3.3% together
TEI works in engine development, parts manufacturing and maintenance, repair and overhaul (MRO). The engines it develops and produces include the PD170 piston engine for unmanned aircraft (used on AKINCI and AKSUNGUR), the indigenous TS1400 turboshaft for the GOKBEY helicopter, the TF6000 jet-engine development programme, and the TF35000, an indigenous engine targeted for the KAAN fighter. The TF35000 is a development target and is not yet ready for serial production. TEI also holds an MRO agreement for the GE F110 engine and manufactures engine parts for global primes such as GE, Pratt & Whitney and Rolls-Royce.
Alongside its equity affiliates, TUSAS runs international industrial and programme partnerships that involve no shareholding. These take the form of licensed production, co-development or structural work packages. The table below summarises the main cooperations; historical changes, such as the end of the F-35 work share, are noted separately.
The scale of these affiliates and partnerships reads more clearly against the size of the parent company. TUSAS ranked 47th on the Defense News Top 100 (2025) list and reported roughly 2.2 billion dollars in defence revenue.
Ecosystem partners: subsystem suppliers, not affiliates
Several large Turkish defence firms that work on TUSAS platforms are often mistaken for subsidiaries, but they are in fact ecosystem partners: companies that supply subsystems without any shareholding link. ASELSAN covers avionics, radar and electro-optics; HAVELSAN covers software and simulation; and ROKETSAN and TUBITAK SAGE cover munitions. TEI on the engine side sits in a dual position, since it is both an ecosystem supplier and an affiliate in which TUSAS holds the majority stake. At the centre of this structure, TUSAS acts as the prime contractor, handling design and integration; not every subsystem on a platform is a TUSAS product.
Why does the affiliate-versus-partnership distinction matter?
TUSAS producing parts for Airbus or Boeing is sometimes read publicly as an ownership relationship. In reality, the tie with these firms is a work-package partnership with no equity: TUSAS makes structural parts and composites for their aircraft, but it is neither their partner nor a shareholder. The F-35 work share was likewise a supply relationship; it ended when Turkey was removed from the programme in 2019. TEI, TCI and EUROTAI, by contrast, are genuine affiliates and joint ventures, because TUSAS holds equity in their capital. The distinction matters for reading correctly which technology is an indigenous capability and which is external supply or licensed production. For unconfirmed ownership splits and contract details, dated official sources should be treated as authoritative.
This article treats subsidiaries (equity holdings) and partnerships (licence / work packages) separately. TEI’s ownership split (TUSAS 50.5% · GE 46.2%) is verified; the Turkish Airlines / TUSAS / HAVELSAN split within TCI has not been officially disclosed in detail. The TF35000 indigenous engine is a target and is not yet ready. The F-35 work share ended when Turkey was removed from the programme in 2019.
Frequently Asked Questions
What are the subsidiaries of TUSAS?
The main TUSAS subsidiaries are TEI (TUSAS Engine Industries) in engines, TCI (Turkish Cabin Interior) in cabin-interior systems, and EUROTAI in helicopter structural production. A subsidiary means a company in which TUSAS holds a stake in the capital. Beyond these equity affiliates, the company also runs international industrial and programme partnerships that involve no shareholding at all.
Does TUSAS own TEI?
TEI (TUSAS Engine Industries) is an affiliate in which TUSAS holds the majority stake. In the company, founded in 1985, TUSAS holds 50.5%, General Electric holds 46.2%, and TSKGV together with THK hold 3.3%. TUSAS is therefore TEI’s largest shareholder, but TEI is a separate legal entity that develops and manufactures aero-engines in Eskisehir.
Which companies own TCI?
TCI (Turkish Cabin Interior) is a joint venture of Turkish Airlines, TUSAS and HAVELSAN, founded in 2010. It produces aircraft seats, galleys, lavatories and in-flight entertainment and connectivity (IFEC) systems. In 2023 it merged with the seat maker TSI and the in-flight entertainment firm Cornea, with facilities in Istanbul and Seattle. The partners’ exact ownership shares have not been officially disclosed in detail.
Is TUSAS a partner of Airbus and Boeing?
No. The TUSAS relationship with Airbus and Boeing carries no equity; it is a work-package partnership. TUSAS makes structural parts and composites for Airbus (A350, A320 family) and Boeing (787 and others) aircraft. It is therefore a supplier and work-package partner, not a shareholder. EUROTAI is a separate joint venture set up with Airbus Helicopters, which is a distinct arrangement.
Under which partnership was the T129 ATAK built?
The T129 ATAK is the product of a licence and co-development partnership set up with the Italian firm AgustaWestland (today Leonardo); it was developed from the Italian A129 Mangusta to meet Turkey’s requirements. It is a good example of a programme partnership TUSAS runs with an international prime, with serial production and integration of the ATAK carried out by TUSAS.
Is TUSAS still involved in F-35 production?
No. TUSAS was previously a supplier holding a structural-parts work share in the F-35 (Joint Strike Fighter / JSF) programme. However, Turkey was removed from the programme in 2019, and that work share ended. The F-35 work share is therefore a historical relationship today, not a current partnership.
Is an ecosystem partner the same as a subsidiary?
No. Firms such as ASELSAN, HAVELSAN, ROKETSAN and TUBITAK SAGE are ecosystem partners that supply subsystems like avionics, software and munitions to TUSAS platforms; TUSAS holds no equity in them. A subsidiary, by contrast, is a company in which TUSAS holds a stake in the capital (TEI, TCI, EUROTAI). TEI holds both roles at once, as both an engine supplier and an affiliate.
Sources
- TUSAS official corporate site — tusas.com
- TEI (TUSAS Engine Industries) official site — tei.com.tr
- GE Aerospace press releases — TEI joint venture and F110 MRO announcements
- Defence Industry Agency (SSB) — programme and cooperation announcements
- Defense News Top 100 (2025 list) — company ranking and revenue data
- Wikipedia — Turkish Aerospace Industries and TUSAS Engine Industries entries
