Tejas light combat aircraft bulks up into medium weight category

The Tejas light combat aircraft (LCA), which was developed to replace the MiG-21/MiG-27 light fighters in the Indian Air Force (IAF), will not remain a light fighter much longer.


Numerous additional capabilities demanded by the Indian Air Force (IAF) for the Tejas Mark 2, which is still on the drawing board, will increase the weight of the 14.5 tonne aircraft by three tonnes, into the 17.5 tonne medium fighter class.


“We now call the Tejas Mark 2 a medium weight fighter, or MWF”, said a senior Tejas designer in a classified briefing in New Delhi on Friday, which Business Standard attended.


Consequently, the Tejas Mark 2 is now being billed by the IAF as a replacement for the Mirage 2000 medium fighter, rather than the lightweight MiGs that are retiring soon.


Changes in defence equipment specifications demanded by the buyers — the army, navy and IAF — are partly responsible for endemic delays in developing indigenous weaponry. Hindustan Aeronautics Ltd (HAL) has cited the IAF’s repeated changes in Tejas Mark 1 specifications as a reason for production delays.


The Tejas’ changing goalposts

However, this is probably the first time that user-driven changes are driving a weapons platform into an altogether different category.


The briefing explained that the transformation of the Tejas from a light to a medium fighter has taken place incrementally over the preceding decade. In 2009, the Tejas Mark 2 was sanctioned as a “re-engined” version of the Tejas Mark 1, with the current General Electric F-404IN engine replaced by a GE F-414 engine with higher thrust.


During the three years it took to buy the F-414 engine, the IAF kept demanding additional systems and improvements in the existing ones. By 2014, when the Tejas Mark 2’s preliminary design review (PDR) was conducted, the aircraft fuselage design was stretched by half a metre and it became one-and-a-half tonnes heavier. Compared to the 3.5 tonnes of payload (mainly weapons and external fuel) envisioned in the initial design, the Tejas Mark 2 was now to carry 4.5 tonnes — one tonne more.


Meanwhile, the IAF and HAL conceived an interim fighter called the Tejas Mark 1A, with additional capabilities like an active electronically scanned array (AESA) radar and an advanced electronic warfare suite. By 2017, the IAF demanded all those capabilities and more in the Mark 2.


The 2017 Tejas Mark 2, therefore, became a full metre longer. With an all-up weight of 16.5 tonnes and a payload of 5.5 tonnes, it was already pushing the medium fighter border. The IAF also demanded that it carry 3.3 tonnes of internal fuel, almost a tonne more than what was envisaged in 2009.


Last year, the Tejas Mark 2 transitioned fully from an LCA to a “medium weight fighter” (MWF). It will now be 1.35 metres longer and significantly broader than the original Mark 2, and will carry 6.5 tonnes of payload — more than double the original plan.


“The Tejas Mark 2 MWF is now required to have greater range and endurance. It will have 11 weapons stations, compared to the earlier seven and will carry weapons like the SCALP missile, and the Crystal Maze and SPICE-2000 guided bombs”, said the Tejas designer.


An aviation analyst, speaking off the record, said these ambitious specifications would almost certainly delay the Tejas Mark 2 significantly, since the designers must effectively create a brand new aircraft by the target year of 2025.


“The IAF has steadily moved the goalposts for the Tejas. This is only the latest example,” says the analyst.

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