Turkey joins the rotary club

First revealed at the IDEF (International Defence Industry Fair) at the Tüyap İstanbul Fair and Congress Centre in May 2017, and subsequently shown in the static display at the Paris Air Show in July, the TAI-625 is Turkey’s first fully indigenous helicopter.
More than a simple mock-up, the T625 shown at Paris was largely based on a production-representative fuselage and other fully engineered components.
The Paris appearance was described as being part of a pre-marketing product awareness campaign, but serious work is already under way on the programme, with construction of the first prototype having begun in July 2016.
The T625 is a 12-passenger, 6tonne medium twin helicopter, designed to operate in hot and high environments and adverse weather conditions, and intended to compete with helicopters like the Leonardo AgustaWestland AW139 and the Airbus H175.
The helicopter is an attractive, modern-looking design and is broadly reminiscent of the Airbus H155 and the AW139 in appearance and configuration. It has a conventional but fully retractable undercarriage, with twin nose-wheels and single main undercarriage wheels, and is fitted with a five-bladed main rotor and a conventional four-bladed tail rotor.
The aircraft features a flat cabin floor that can be configured for passenger or VIP transport, emergency medical services, cargo, offshore transport, and search and rescue missions, and has large sliding cabin doors on each side, with separate outward-opening cockpit doors. It will be equipped with a four-axis dual redundant automatic flight control system.
TAI began the detailed design of the T625 in 2013 under the name Ozgun, after a programme launch in June 2010. The numerical T625 designation was substituted in January 2017 with the initial ‘6’, representing the helicopter’s six tonne gross weight, ‘2’ indicating the two engines and ‘5’ the number of main rotor blades.
The T625 programme builds on TAI’s successful development of the T129 Atak helicopter, a licence-built and extensively upgraded variant of the AgustaWestland AW129 Mangusta, which incorporates Turkish-developed avionics, self-protection equipment and weapon systems. Some 22 examples from an initial order for 59 units have been delivered to the Turkish army, and one further aircraft has been retained as a test platform.
Negotiations for a second batch of at least 25 helicopters are already under way, and TAI is reportedly in negotiations with Pakistan for an officially undisclosed number of T129s (thought to be 30).
TAI is also producing 109-121 Lockheed Martin/Sikorsky S-70i International Black Hawk helicopters for the Turkish Armed Forces under the Turkish utility helicopter programme (TUHP), a major manufacturing project that promises to give the company invaluable experience in the mass production of advanced rotorcraft.
Development of the T625 was largely driven by domestic requirements, and though there is, as yet, no launch customer for the type, the Turkish Government has reportedly expressed an interest in placing a multi-aircraft order, probably starting with an order for police helicopters for the Jandarma (a branch of the armed forces, reporting to the Ministry of the Interior) and/or for the Turkish National Police, controlled by the General Directorate of Security.
Turkey is also witnessing steady growth in its domestic helicopter market and TAI hopes to sell T625s for parapublic roles, including helicopter emergency medical (HEMS), air ambulance, law enforcement, fire-fighting and rescue, and also for executive and VIP transport. There is also a strong military market, with a pressing need to replace the Turkish armed forces’ ageing fleet of Bell Model 205/UH-1Hs.
TAI sees a total domestic market for up to 300 T625s over the next 15 years. It also hopes for healthy export sales, another 400-500 airframes over a 20-25 year period.
The company is further hoping that Ankara’s foreign relations might allow it to secure orders in markets that may not be so easy for rivals like Airbus Helicopters and Lockheed Martin/Sikorsky.
The T625 is initially being developed for the civil transport market and the military version will follow about two years after the first flight. That variant will be optimised for troop transport, search and rescue, and casualty evacuation missions.
The first of three flying prototypes is expected to make its maiden flight in September 2018, with the second following in about March 2019.
The first two prototypes will be representative of the planned civilian version, while the third will represent the military variant. There will also be a number of ground-test aircraft, including a transmission test rig, a structural and fatigue test ‘iron bird’, and an avionics test rig assigned to Aselsan.
Turkish civil certification is expected in mid-to-late 2020, and European Aviation Safety Agency (EASA) certification will follow.
The T625 will be an almost entirely indigenous Turkish helicopter, although Sikorsky will be a major subcontractor, and Spanish firm CESA will be responsible for hydraulic systems.
Initially the helicopter will be powered by an imported engine, in the shape of the Rolls-Royce Light Helicopter Turbine Engine Co (LHTEC) CTS800-4A (T800) turbine engine, which was chosen for commonality with the T129 attack helicopter. The T625 will be the first commercial helicopter to be powered by the T800 engine.
In time, even the helicopter’s powerplant will be made in Turkey, since Tusas Engine Industries (TEI) is already developing an indigenous TS1400 turboshaft engine for the T625 and the T129 under the turboshaft engine development project (TEDP), which was formally launched in February 2017.
The new TEI engine is also intended to power new versions of the TAI Hürkuş turboprop trainer and light combat aircraft.
Development of the new engine is expected to take 7-10 years, with design accounting for two years and prototype production and testing taking another four-and-a-half.
Until then, all T625s will be built with the LHTEC powerplant, which is expected to give a cruise speed of roughly 150 knots, and an endurance of about 3.8 hours, with a full fuel load of 2,248lb (1,020kg).
Everything else on the production T625 is expected to be ‘made in Turkey’, and even the main gearbox and transmission is being developed in-house, with the support of several international consultants.
Testing of the first prototype gearbox, which is being produced by an unnamed outside supplier, will begin later in 2017, but TAI will also manufacture its first two in-house gearboxes this year.
Other Turkish partner companies include engineering and manufacturing firm Alp Aviation, which will be responsible for the production and assembly of the landing gear, and of some gearbox and dynamic components.
Aselsan, Turkey’s biggest defence electronics company, will supply the T625’s on-board electronics, including a newly-developed avionics suite. This will feature two large wide-area touchscreen displays (one per pilot) showing flight data and map and engine information on the main panel, with two more touchscreens for flight planning, radios and aircraft system on the centre pedestal. The cockpit is designed to allow VFR and IFR single-pilot operation.
The military version of the T625 would probably be equipped with a variety of Aselsan systems, including the company’s active phased-array electronic warfare and countermeasures system.
The T625 is intended to be the first model in what is planned to be a family of indigenous helicopters, spanning the size range from 3.5tonnes up to 10-12tonnes. A four-seat training helicopter is expected to be the next model in TAI’s new helicopter family, but is unlikely to be launched until T625 development is complete.