DRDO/ADA/HAL's Naval Version of TEJAS light fighter

The recent withdrawal of the move to import 114 ‘Single-Engine Fighters’ (SEF) by India’s Ministry of Defence (MoD) opens a window of opportunity for the Aeronautical Development Agency (ADA), controlled by the Defence Research & Development Organization (DRDO), to rekindle its effort to develop a MK-II variant of the Tejas light combat aircraft (LCA). Because, even though reports suggest that MoD is planning to replace the SEF competition with a larger competition that will see both single and twin- engined jet fighters in contention (in a manner reminiscent of the failed multi-role medium range combat aircraft [MMRCA] tender from a decade ago), the most realistic way to augment the Indian Air force’s (IAF’s) combat strength continues to be the building of more Tejas variants, as we have argued before. As such, it is now time for DRDO to use its internal allocations to fund the further development of the Tejas MK-II, with full support from MoD, in order to be future ready given that fighter import tenders take a lot of time in India and may never actually reach fruition, judging by recent experience.

The Mk-II Design Must Return

ADA, has long proposed a Tejas MK-II with a more powerful engine than the baseline MK-I, as well as aerodynamic refinements, to address the IAF’s 1995 air staff qualitative requirements (ASQR) with respect to kinematic performance. After all, one of the regrets of the IAF has been the fact that the MK-I design does not meet the ASQR in terms of sustained turn rate (STR), transonic acceleration and climb rate. The developers of the Tejas, i.e. ADA, however believe that the MK-II design, which will also incorporate a pair of canards, will be able to address MK-I’s shortfalls in terms of aerodynamic performance. The 1995 ASQR apparently requires a STR of 18 degrees (same as the F-16’s) and Mk-II will close in on that. The climb rate will also be more or less satisfactorily reached. Transonic acceleration is expected to be realized fully. Moreover the Mk-II airframe will be able to reach a top speed of Mach 1.8 at altitude.

Development work on MK-II had been progressed by ADA over the years as part of the overall allocations for the LCA program. Currently, ADA’s work on the Tejas is being financed via the LCA Phase-III project which was sanctioned in November 2009 with an allocation of Rs 2,431.55 crores and is scheduled to be complete by December 2018. Most of this allocation has gone towards developmental activities related to achieving operational clearances for the MK-I design as well general development work on the Tejas design family (Air force version). However, while funds from this allocation have helped advance the Tejas MK-II design to a level where the ‘inboard’ i.e the complete layout for Mk-II is ready and plenty of wind tunnel work into adding a pair of canards has also been done, it is not enough for ADA to develop a pair of MK-II prototypes. For that, fresh allocations are required.

Now while the SEF proposal was in vogue, there was this general belief in the fighter development community in India that there was perhaps no point in pursuing the Mk-II variant, since it was unlikely to receive orders given that the IAF seemed to be keen on importing a fighter in the same class instead. However, with the SEF proposal going nowhere and its successor unlikely to yield early returns either, the time is ripe for DRDO to fund ADA on its own to develop a pair of MK-II prototypes. The finance wing of India’s MoD must greenlight such an effort along with the total support of the Defence Minister. Development work on the MK-II has progressed sufficiently for ADA to achieve first flight with a prototype within 2-3 years of funds being allocated.

ADA’s confidence with respect to this timeline also stems from the fact that modifications to the 98 kilo newton generating F414-GE-INS6 (F414), in order for it to fit the MK-II design, have already been certified by the Center for Military Airworthiness and Certification (CEMILAC). What is more, eight of the 99 F414 engines ordered by ADA earlier have already been delivered to it by GE. Clearly, ADA now has some engines waiting for an airframe, i.e MK-II. The F414-GE-INS6 is of course more powerful than the F-404-GE-IN20 (F-404) engine that currently powers MK-I.

Moreover, the Mk-I design has some 25-30 percent commonality in parts with MK-I and these parts (i.e not requiring any modification) are already in production. For the MK-I parts that have to be replaced, thousands of new drawings have being worked upon jointly by DRDO- Hindustan Aeronautics Limited (HAL) along with the private sector and these are now ready. Clearly, the stage is set for the early creation of two prototypes that will probably cost some Rs 3000-4000 crores and can be funded by DRDO directly. Once the efficacy of this effort is demonstrated to the ‘user’ i.e the IAF, they can fund the rest of the development effort all the way to certification which is expected to take 2 years from first flight. If sanctioned early this year, Tejas MK-II could be easily be in production by the time HAL finishes producing the last of the 83 Tejas MK-1A for which it recently received a request for proposal from the IAF. The IAF is of course fully aware of the nature of Tejas MK-II given that it has positioned 23 officers to support the overall Tejas program and according to sources ADA has had several discussions with the IAF about it.

Not Just More Agile

While the Mk-II design is expected to achieve a 5 percent improvement in drag characteristics through ‘production improvements’ related to further streamlining (reduced contour variations etc) of the Mk-I airframe, it is actually a step up from the baseline MK-1 and even the improved MK-1A in other ways as well.

With only 25-30 percent parts commonality with Mk-I or Mk-IA, MK-II will have many modernized line replace units (LRUs) which will serve the purpose of both obsolescence management and improved maintainability. MK-II will also have a higher maximum take-off weight reflected in the carriage of more on-board fuel thereby increasing endurance. (endurance will also be helped by its better aerodynamics). MK-II will have a new indigenous flight control computer and will see refinements in the control law for the LCA design as well.The glass cockpit for the Mk-II is going to be new as well. For one it is going to feature bigger 8 x 12 inch displays rather than the 5 x 5 and 6 x 6 inch displays currently featured in the MK-I cockpit. A prototype of the Mk-II cockpit already exists. The MK-II displays are likely to be supplied by India’s Samtel.

While HAL is looking to outfit MK-1A with an imported active electronically scanned array (AESA) and a foreign self-protection jammer, MK-II should fly with the indigenous Uttam AESA being developed by DRDO’s Electronics and Radar Development Establishment (LRDE) and the ‘unified electronic warfare suite’ (UEWS) created by the Defence Avionics Research Establishment (DARE), another DRDO lab, in partnership with Israel’s Elisra. Uttam, which weighs 120 kg, has been put through extensive ground evaluation by LRDE and is reportedly ready for integration onto a Tejas test vehicle. UEWS is currently undergoing tests on the Tejas PV-6 prototype vehicle.

A Modular ‘Make in India’

Not only is MK-II supposed to be a superior product in terms of performance, it will also lend itself to being produced quicker, as is the need of the day. ADA has done of a lot of work together with HCL with the objective of making the Mk-II design ‘modular’. In this modular scheme of things, HAL as the integrator will receive 8-10 Tejas MK-II ‘modules’ as sub-assemblies from domestic private companies such as L&T and will then put them together to build a complete aircraft ready for checkout and flight testing. Each of these module suppliers will therefore be ‘Tier-I’ suppliers to HAL and will receive LRUs from Tier-II suppliers (w.r.t to HAL) for integration into the modules, which will then be dispatched to HAL. According to Dr K.Tamilmani, former Director General Aeronautics, DRDO, ‘The idea is to ‘terminate’ things like electrical looms, hydraulic pipes, fuel line pipes etc. at the module level which can then be connected with other such modules.’

Of course, for the Tejas Mk-II program to be an all-round success in the industrial sense, the time has come for India to get GE to produce the complete F-414 engine on Indian soil in association with a domestic partner. In this light, the setting up of a joint venture between GE and Tata Advanced Systems Limited (TASL) in Adibatla for the manufacture of various components of GE engines looks like a timely development. This JV which will see the setting up of tooling that can produce F-414 parts, can be encouraged by the Indian Government to take on the production of the entire F-414 engine under manufacturing know how transfer from GE.

The F-414 can actually be retro-fitted onto the Mk-I/IA airframes also since the existing intake of these aircraft can easily handle the additional mass flow from the F-414 as compared to the F-404. Of course, other modifications to the Mk-I/IA airframe will be required for this purpose. In the course of its lifetime any single-engined jet fighter needs about 3.5 jet engines. So a hypothetical run of at least 200 Tejas MK-II in addition to the 123 Mk-1/1A (modified to field the F-414) that are on order will mean that the IAF’s future fleet will require north of 1100 F-414 engines in the course of their service life. Clearly, GE should not have any compunctions in transferring know how for even the F-414 core for an order of that size. Perhaps, the India-US ‘joint working group on jet engine technology’ should burn some midnight oil to explore this potential.