Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

[Picklu]

https://twitter.com/SJha1618/status/1009407080233619456

Saurav Jha
@SJha1618
France's Safran Aircraft Engines, which carried out a technical audit on @DRDO_India's Kaveri jet engine development program, has stated in a report that the engine had attained sufficient maturity to be integrated with an aircraft for limited envelope flight testing.

https://twitter.com/SJha1618/status/1009413687222919170

Saurav Jha
@SJha1618
This is as per what DRDO says in its Annual Report for 2017.

[Trikaal]

Admiral, you are not getting it. I am not advocating uncertified kaveri; For squadron service, I want certified kaveri only.

Is mk1a flying? is mk2? didn't iaf order 83 mk1a and 201 mk2? This is basically a vote of confidence from IAF that they will induct that many as long as mk1a, mk2 get certified.

I would like a similar order of mk1 with kaveri.

Even a certified kaveri remains untested/unproven without squadron service; similar to what LCA mk1 was till LSP.

No firm orders for either Mk1A or Mk2 as of today. The only firm, on paper signed and stamped order is for 40 Mk1s. Mk1A and Mk2 numbers are just an expression of interest. However, it doesn't matter too much since ghar kii hii baat hai. As soon as HAL is ready with the product, there will be cost negotiations and deal will be signed. They cannot sign a deal for an under-development product.

As for Kaveri, IIRC, the French have only audited(or whatever they did) it for only 52 kN dry thrust which is not sufficient for Mk1. So unless Kaveri can be uprated, I don't see HAL putting it on Tejas. In my opinion, there is no plan to put Kaveri on Mk1 or Mk1A. The fighters they are aiming for are Mk2 and AMCA. That gives the engine sufficient time to develop.

[Picklu]

No firm orders for either Mk1A or Mk2 as of today. The only firm, on paper signed and stamped order is for 40 Mk1s. Mk1A and Mk2 numbers are just an expression of interest. However, it doesn't matter too much since ghar kii hii baat hai. As soon as HAL is ready with the product, there will be cost negotiations and deal will be signed. They cannot sign a deal for an under-development product.

Well, a similar expression of interest for kaveri equipped mk1 would be good.

As for Kaveri, IIRC, the French have only audited(or whatever they did) it for only 52 kN dry thrust which is not sufficient for Mk1. So unless Kaveri can be uprated, I don't see HAL putting it on Tejas. In my opinion, there is no plan to put Kaveri on Mk1 or Mk1A. The fighters they are aiming for are Mk2 and AMCA. That gives the engine sufficient time to develop.

Not sufficient for mk1 why? 52kn dry thrust was the design objective. Yes, there will be performance shortfall of the plane in certain regime.

So what? The experience of testing on an actual plane, certifying and finally squadron service would be worth it for developing kaveri mk1a, kaveri mk2 and so on

IAF can use kaveri equipped mk1 for less demanding regime like initial conversion training purpose

[nam]

Kaveri, until it can prove consistency will be not be deployed on a single engine fighter like LCA. It may be okay for 2 engine, if one fails the other will be present.

Kaveri, the way I see will go on to UCAV first. It makes sense. Better to crash a UAV, than a jet with a human in it.

[Picklu]

Kaveri, until it can prove consistency will be not be deployed on a single engine fighter like LCA. It may be okay for 2 engine, if one fails the other will be present.

Kaveri, the way I see will go on to UCAV first. It makes sense. Better to crash a UAV, than a jet with a human in it.

Flying test bed, ucav etc are all fine but kaveri should be certified for single engine operation and put on a lca for squadron service. Even if performance is below advertised.

Without kaveri, 83 mk1a and 201 mk2 are strategic risks

[nam]

Flying test bed, ucav etc are all fine but kaveri should be certified for single engine operation and put on a lca for squadron service. Even if performance is below advertised.

Without kaveri, 83 mk1a and 201 mk2 are strategic risks

I don't see Kaveri maturing for SE fighter for atleast for 10 years, even if it flies now. Look how long the Chinis are taking, with an open cheque book.
By this time, we would be in a transition period b/w manned & unmanned jets.

If we make a decision that 2030 onwards, we want majority of fighters to be supersonic UCAV. then Kaveri would fit perfectly. So it makes sense for us to concentrate Kaveri for UCAV, as safety margin will be less.

We have the option of EJ200 if there are concerns overs F414s for MK2.

[Khalsa]

So much wealth of knowledge here that needs to be in the Kaveri thread as well.

[ks_sachin]

Kaveri, until it can prove consistency will be not be deployed on a single engine fighter like LCA. It may be okay for 2 engine, if one fails the other will be present.

Kaveri, the way I see will go on to UCAV first. It makes sense. Better to crash a UAV, than a jet with a human in it.

Flying test bed, ucav etc are all fine but kaveri should be certified for single engine operation and put on a lca for squadron service. Even if performance is below advertised.

Without kaveri, 83 mk1a and 201 mk2 are strategic risks

Picklu come on man. Kaveri cannot be put on a LCA before it demonstrattes some level of reliability.

First it has to prove that it is safe for the pilot. Otherwise the rate of folding parachutes will be higher than rate of manufacture!!!

Even performance has to meet some basic parameters.

[Trikaal]

The major problem Kaveri was facing until now was that it was stalling in certain flight regimes. That problem has supposedly been solved by the French but untill it can be proven beyond a shadow of doubt, there is no chance of putting it on a Single Engine Fighter. We need to remember that even a single crash death might sound the death knell for this entire program. We are not China or Russia. So we have to be extra careful.

Also, IAF won't accept it for any combat role unless the engine can be uprated. So there's that.

[ArjunPandit]

The major problem Kaveri was facing until now was that it was stalling in certain flight regimes. That problem has supposedly been solved by the French but untill it can be proven beyond a shadow of doubt, there is no chance of putting it on a Single Engine Fighter. We need to remember that even a single crash death might sound the death knell for this entire program. We are not China or Russia. So we have to be extra careful.

Also, IAF won't accept it for any combat role unless the engine can be uprated. So there's that.

We should leave the threat of entire program at risk because of one crash behind us. IAF, and MoD are ahead of this. Not that I want this kind of tragedy or look forward to it, especially having seen a colleague's family go through a Mig 23 crash. However, at least we within BRF should put the narrative of doubling down or committing more on the program to give a fitting tribute to those who risked their lives in first place. We made this mistake in AWACS and much before that.

[ks_sachin]

Commit more to the program but follow protocol and only mate with LCA when the engine crosses some reliability benchmarks. Right now if we dont know why it stalls how can we put it on an ac?

[Lalmohan]

the stall is most likely due to the inlet flow, which is the airframe external to the engine
in transonic flight regimes this is a common problem in fast jet design

[Rakesh]

Picklu, see this article from April 2017....

Foreign expertise key to fire up India's jets
https://www.deccanherald.com/content/60 ... re-up.html

The recent pronouncement from snecma is that kaveri is ready to fly on a plane (not engine test bed but an actual plane)

Yes Picklu, but you do not raise an *ENTIRE* squadron for that purpose

You test it on a LSP, ensure that it meets design parameters and certify it. And then and *ONLY* then can you introduce it into regular IAF service. I am oversimplifying the process and someone more knowledgeable can provide a more detailed path for Kaveri induction (from where it stands right now) into regular service.

But the point is, an operational squadron does not test unproven platforms - engine, aircraft, weapon systems, etc. That is the job of an organization like the Aircraft Systems & Testing Establishment (ASTE) or something similar.

[Picklu]

The recent pronouncement from snecma is that kaveri is ready to fly on a plane (not engine test bed but an actual plane)

Yes Picklu, but you do not raise an *ENTIRE* squadron for that purpose

You test it on a LSP, ensure that it meets design parameters and certify it. And then and *ONLY* then can you introduce it into regular IAF service. I am oversimplifying the process and someone more knowledgeable can provide a more detailed path for Kaveri induction (from where it stands right now) into regular service.

But the point is, an operational squadron does not test unproven platforms - engine, aircraft, weapon systems, etc. That is the job of an organization like the Aircraft Systems & Testing Establishment (ASTE) or something similar.

Quoting self once again for your benefit; read the bold line below to understand what I meant by unproven.

Admiral, you are not getting it. I am not advocating uncertified kaveri; For squadron service, I want certified kaveri only.

Is mk1a flying? is mk2? didn't iaf order 83 mk1a and 201 mk2? This is basically a vote of confidence from IAF that they will induct that many as long as mk1a, mk2 get certified.

I would like a similar order of mk1 with kaveri.

Even a certified kaveri remains untested/unproven without squadron service; similar to what LCA mk1 was till LSP.

However, place the order (or expression of interest or whatever) now as a vote of confidence. Let the whole world know that IAF is behind kaveri powered lca.

[Rakesh]

Even a certified kaveri remains untested/unproven without squadron service; similar to what LCA mk1 was till LSP.

Picklu, that is incorrect. When the Kaveri turbofan enters an operational squadron it is *FULLY* tested/proven/certified. There is no more testing left to do at that stage. Testing and certification will be complete at that point.

You are assuming that the IOC for the Tejas Mk1 - which flies with No 45 Flying Daggers Sqn - can be applied to the engine as well. That premise is false.

[Trikaal]

^To add to that, IAF never orders an engine. That's not their job, or expertise. Have you ever heard IAF propose an engine? That is GTRE or ADA's job. Even Uttam isn't IAF's responsibility, they are only interested in the final product. It's DRDO that is spearheading Uttam development.

[nrshah]

If Kaveri cannot be certified for single use, India should design all the planes with two engines...
You have to use what you have,not import...

[VKumar]

Whether a Kaveri can be installed in a Tejas? And can trials such as taxiing be safely conducted by a Kaveri installed Tejas? Will such experiments yield any useful information?

[Picklu]

Even a certified kaveri remains untested/unproven without squadron service; similar to what LCA mk1 was till LSP.

Picklu, that is incorrect. When the Kaveri turbofan enters an operational squadron it is *FULLY* tested/proven/certified. There is no more testing left to do at that stage. Testing and certification will be complete at that point.

You are assuming that the IOC for the Tejas Mk1 - which flies with No 45 Flying Daggers Sqn - can be applied to the engine as well. That premise is false.

RD33, Al 31 FP - examples galore that certification is not the end of the road but just a milestone; only during squadron service the engine is really proven.

Anyway, this is semantics.

The main point is order (or express of interest or whatever) now of 1 squadron of mk1 with "certified" kaveri; whenever in the next 5/6 years that certification comes.

If the certification gets delayed by more than that and mk1a airframe is fully debugged by then, convert the order (or expression of interest) to 1 squadron of mk1a with kaveri, similar to conversion of 2 seater to FOC version due to delay of finalization of the SOP.

This order (or expression of interest) is exactly similar to the order (or expression of interest) of 201 mk2

[ramana]

Picklu et al we are running ourselves into circles.
The Tejas Mk1A and Mk2 have already designated engine. GE 414.

Kaveri is coming along.
Yes it has to be certified before it gets integrated in Tejas.
When it is ready it will be flown on one of the LSPs.

i remember some 1000 hours of bench testing as a benchmark.

As to IAF commitment they have agreed to 83 Mk1A and the 16 trainers. And for further ~200 Mk2s.
They can't order as it is long process of budgets, MoD etc.

[Picklu]

Picklu et al we are running ourselves into circles.
The Tejas Mk1A and Mk2 have already designated engine. GE 414.

Kaveri is coming along.
Yes it has to be certified before it gets integrated in Tejas.
When it is ready it will be flown on one of the LSPs.

i remember some 1000 hours of bench testing as a benchmark.

As to IAF commitment they have agreed to 83 Mk1A and the 16 trainers. And for further ~200 Mk2s.
They can't order as it is long process of budgets, MoD etc.

If you notice, IAF has not given the same commitment to kaveri what it has given to mk2 which is a paper plane at this point of time with a completely new engine (in indian context).

And the ask is not something new. LCH, LUH, HJT 36, HTT 40, heck even NAL Saras has a standing "expression of interest" of 1 squadron from IAF

mk1a is ge 404, btw

[Rahul M]

err, Picklu, IAF does not give commitments to individual a/c parts. it hasn't shown any commitment whatsoever for AMCA's tailplanes for example, or FGFA's nosewheel.

[Picklu]

Err, RM, Engine and Radar are not just individual a/c parts like tail planes or nosewheels.

mk2 got accepted with GE414 instead of EJ200, are you saying IAF had no say on that matter? Or the Re-engine of Jags, going against the OEM choice of engine?

What was that news of EL/M2052 ToT condition of being selected for at least 2 different type of IAF fighters and IAF discussing the same?

It seems IAF do commit for these parts.

[Rakesh]

RD-33, AL-31FP - examples galore that certification is not the end of the road but just a milestone; only during squadron service the engine is really proven.

Anyway, this is semantics.

Picklu, come on! The above is anything but semantics.

RD-33 is from Klimov and AL-31FP is from UEC Saturn (formerly Lyul'ka-Saturn, but merged with Rybinsk Motors). These are engine manufacturers with a number of certified turbofans coming out from their stables. Both have a history of jet engine design that starts from the end of the Second World War! Where is GTRE's track record compared to Klimov and UEC Saturn?

And certification is required for each particular variant of the engine.

In Klimov's case, the RD-33MK (on the IN's MiG-29K) had the baseline RD-33 (on the IAF's MiG-29s) to fall back on. But both engines had to be certified. It does not work any other way.

In UEC Saturn's case, the AL-31FP (on the Su-30MKI) had the AL-31F (a certified engine on the Su-27) to fall back on.

What baseline engine does the Kaveri have?

And to ask GTRE to take the risk - that you are advising - would be tantamount to suicide for GTRE as an organization and to the pilot who has to fly the plane in an operational squadron. Engines are NOT proven in squadron service - I am puzzled as to where you are getting this from. Engines are proven during testing. In squadron service, there are a set of SOPs that the pilot follows during flight and a set of SOPs that the ground crew follows during service/maintenance. It is not the job of an IAF pilot to prove the Kaveri in squadron service. That is GTRE's job and ASTE's job. You are mixing the two up.

The main point is order (or express of interest or whatever) now of 1 squadron of mk1 with "certified" kaveri; whenever in the next 5/6 years that certification comes.

Which can only happen after GTRE and ASTE certify the engine. Once that milestone is crossed, there is no need for only one squadron of Kaveri-powered Tejas

If the certification gets delayed by more than that and mk1a airframe is fully debugged by then, convert the order (or expression of interest) to 1 squadron of mk1a with kaveri, similar to conversion of 2 seater to FOC version due to delay of finalization of the SOP.

This order (or expression of interest) is exactly similar to the order (or expression of interest) of 201 mk2

Whatever variant of the Tejas you pick, the turbofan must be certified Picklu.

[Picklu]

RD-33, AL-31FP - examples galore that certification is not the end of the road but just a milestone; only during squadron service the engine is really proven.

Anyway, this is semantics.

Picklu, come on! The above is anything but semantics.

RD-33 is from Klimov and AL-31FP is from UEC Saturn (formerly Lyul'ka-Saturn, but merged with Rybinsk Motors). These are engine manufacturers with a number of certified turbofans coming out from their stables. Both have a history of jet engine design that starts from the end of the Second World War! Where is GTRE's track record compared to Klimov and UEC Saturn?

And certification is required for each particular variant of the engine.

In Klimov's case, the RD-33MK (on the IN's MiG-29K) had the baseline RD-33 (on the IAF's MiG-29s) to fall back on. But both engines had to be certified. It does not work any other way.

In UEC Saturn's case, the AL-31FP (on the Su-30MKI) had the AL-31F (a certified engine on the Su-27) to fall back on.

What baseline engine does the Kaveri have?

And to ask GTRE to take the risk - that you are advising - would be tantamount to suicide for GTRE as an organization and to the pilot who has to fly the plane in an operational squadron. Engines are NOT proven in squadron service - I am puzzled as to where you are getting this from. Engines are proven during testing. In squadron service, there are a set of SOPs that the pilot follows during flight and a set of SOPs that the ground crew follows during service/maintenance. It is not the job of an IAF pilot to prove the Kaveri in squadron service. That is GTRE's job and ASTE's job. You are mixing the two up.

The main point is order (or express of interest or whatever) now of 1 squadron of mk1 with "certified" kaveri; whenever in the next 5/6 years that certification comes.

Which can only happen after GTRE and ASTE certify the engine. Once that milestone is crossed, there is no need for only one squadron of Kaveri-powered Tejas

And that is where you are wrong. Given the situation today, even after certification, Kaveri is not guaranteed to power Tejas or anything else for that matter. Primarily due to its current power and engine life shortfall.

In fact, instead of realistically closing* the gaps between design (52/81) and achieved (52/75) thrust figures in dry/wet regime and then taking it to certification, already talks are on to move to a new design with higher thrust rating.

This way, it won't even reach the certification stage and become a never ending saga of catching up.

Exactly similar to Arjun mk2 saga where after achieving the design features, it is still not ordered and sent for weight reduction exercise. And remember the reasons for not ordering Arjun in bulk. One major among them is dependency on foreign power plant.

Hence the ask of at least 1 squadron of LCA, powered by "certified" but current lower performance spec-ed kaveri, in operational service.

* we may never achieve all the design goals 100% and have to be satisfied with lesser performance in some KPI. LCA mk1 as well as mk1a will remain overweight and consequently won't take 9G turn. Still, Parrikar sir was able to push through 123 LCA of these versions. Thats vision and foresight.

If the certification gets delayed by more than that and mk1a airframe is fully debugged by then, convert the order (or expression of interest) to 1 squadron of mk1a with kaveri, similar to conversion of 2 seater to FOC version due to delay of finalization of the SOP.

This order (or expression of interest) is exactly similar to the order (or expression of interest) of 201 mk2

Whatever variant of the Tejas you pick, the turbofan must be certified Picklu.

This is a strawman argument admiral. Where and when did I advocate putting "uncertified" kaveri on tejas?
The ask, consistently has been to have at least one lca squadron, powered by "certified" kaveri even though the kaveri in its current avatar may not give performance equivalent to ge 404 (let alone ge 414)

[prasannasimha]

This argument is going around in circles. Please stop it. Kaveri can only be integrated when we get a fully tested engine as per norms . So far we do not have it. Once it is achieved we can integrate it. Till then everything is just speculation.

[ks_sachin]

“Hence the ask of at least 1 squadron of LCA, powered by "certified" but current lower performance spec-ed kaveri, in operational service. “

Ok we are all talking at cross purposes.

All agree that it has to be certified I.e. it should be able to fly safely.

Pickle if you had made this statement right at the beginning we would have avoided this needless discussion.

BTW I am in agreement with you althoough I have some reservations on the A/Cs performance.

But yes we need to demonstrate intent.

Admiral the squadron that Picklu talks about will be after the certification by DRDO / ASTE / CEMILAC and mating to a LCA test bed yada yada!!

EOD

[Rakesh]

This argument is going around in circles. Please stop it. Kaveri can only be integrated when we get a fully tested engine as per norms . So far we do not have it. Once it is achieved we can integrate it. Till then everything is just speculation.

Okay, no more from me on this.

Picklu, you win

[ramana]

Picklu, Why didn't you say that earlier?

What you are saying is that DRDO/HAL should use the 52/75 KN Kaveri and see how it performs in squadron service and not wait for the 52/81KN Kaveri.

Mean time they can do product improvement to get to 81 KN or better.

[mody]

The important question right now is if we have ordered the GE-F404 engines for the MK1A aircrafts. No news on the same. Only 40 engines have been ordered for MK1 planes.

HAL will likely finish the manufacture of 16 IOC-2 planes by March 2019. From April onwards production for FOC planes is to begin. The question is whether FOC will be achieved by then and what if gun trials or something else is still pending, whether the production will continue or will stop.
Also, now that the air-air refuelling has been tested, have we ordered the probes and associated hardware from Cobham? If the production is to continue without a break, then these would be required come April. If we have not placed the order as yet, don't know what the lead time from Cobham will be.

The focus should be on getting FOC finished as soon as possible and also ensuring that the production for IOC and FOC planes continue at the rate of 1 per month. This way the SP21 to SP36 planes would be produced by July 2020. Then the production of 8 two seat FOC standard trainers would be taken up, to finish by March 2021.
If MK1A is ready to roll by then, then great, if not then the production for trainers can continue till Jan 2022, to produce another 10 trainers.
From Jan-Feb 2022, production for MK1A will commence, hopefully at the rate of 16-20 per year. The production would go on for 3.5-4 years, by which time, MK2 should be ready for production and production capacity enhanced to minimum 24 planes per annum.

[sankum]

All 18 nos Tejas trainers will be of mk1 standard and will take place after 32 nos single seater Tejas mk1 production and then 73 nos Tejas mk1a will take place.

[prasannasimha]

Kaveri as is cannot be integrated into LCA for two reasons ( that causes delinking ) one was size ( it became larger than originally designed) and weight issues apart from thrust. So the first two initiated the delinking. Not just the thrust.
Not sure what happened thereafter but size was indeed decreased. Not sure about other parameters

[ramana]

All 18 nos Tejas trainers will be of mk1 standard and will take place after 32 nos single seater Tejas mk1 production and then 73 nos Tejas mk1a will take place.

I thought that number was 83 Mk1A

[Kakarat]

All 18 nos Tejas trainers will be of mk1 standard and will take place after 32 nos single seater Tejas mk1 production and then 73 nos Tejas mk1a will take place.

I thought that number was 83 Mk1A

40 Mk1 is 32 fighters + 8 Trainers
83 Mk1A is 73 fighters + 10 Trainers

[Katare]

Since Kaveri’s been separated from Tejas program and like ramana said, all its planned variants have their engines selected as of now, Kaveri has no future with LCA. Besides that current Kaveri even when fully tested would have serious performance shortfalls for today’s and future versions of LCA.

As of now my understanding and guess is that Kaveri will be developed for other platforms like UCAVs. This has been stated (Kaveri without afterburner for UCAV) by DRDO chief at multiple occasions.

Safran’s recommendations for flight worthyness does not make it suitable for LCA but it might make it suitable for a UCAV. It may yet be tested in LCA as it would be easier to mate it with the plateform but Tejas doors have been closed on the Kaveri.

Reengining is a massive (cost, time and Human Resources) and risky undertaking for which there is no room or appetite at ADA or HAL who would rather focus on Mk1, Mk1a, Mk2 and AMCA.

Only way i can see an LCA with Kaveri in IAF colors is, If in an unlikely scenario govt sanctions a program for uprated Kaveri engine with a foreign engine designer as partner. Intil such a program is sanctioned all discussions on Kaveri for LCA have no moorings in hard reality.

[Katare]

It’s been two years since mk1a configuration was agreed upon under MP ( god-bless his soul) still we are at the first stage of RFP. We need serious reforms of our procurement babudom.

[Picklu]

Picklu, Why didn't you say that earlier?

What you are saying is that DRDO/HAL should use the 52/75 KN Kaveri and see how it performs in squadron service and not wait for the 52/81KN Kaveri.

Mean time they can do product improvement to get to 81 KN or better.

Yes Sir, thank you and Ks_sachin to finally get it. Mere certification on a flying test bed or one or two test aircrafts are not enough. We need to get it in squadron service to get all the kinks out.

[Picklu]

Since Kaveri’s been separated from Tejas program and like ramana said, all its planned variants have their engines selected as of now, Kaveri has no future with LCA. Besides that current Kaveri even when fully tested would have serious performance shortfalls for today’s and future versions of LCA.

As of now my understanding and guess is that Kaveri will be developed for other platforms like UCAVs. This has been stated (Kaveri without afterburner for UCAV) by DRDO chief at multiple occasions.

Safran’s recommendations for flight worthyness does not make it suitable for LCA but it might make it suitable for a UCAV. It may yet be tested in LCA as it would be easier to mate it with the plateform but Tejas doors have been closed on the Kaveri.

Reengining is a massive (cost, time and Human Resources) and risky undertaking for which there is no room or appetite at ADA or HAL who would rather focus on Mk1, Mk1a, Mk2 and AMCA.

Only way i can see an LCA with Kaveri in IAF colors is, If in an unlikely scenario govt sanctions a program for uprated Kaveri engine with a foreign engine designer as partner. Intil such a program is sanctioned all discussions on Kaveri for LCA have no moorings in hard reality.

Airframe is designed, tested and initially operated with a proven engine and vice versa. Having a new ucav airframe and kaveri together is not a optimum combo.

[Trikaal]

Tejas Mk1+1A will make up 6 squadrons. IIRC, usually there are 2 trainers per squadron. So why are we ordering an extra 6 trainers? 50% contingency seems excessive.

Also, trainers will be 2 seaters so does that mean their fuel capacity is lower and hence combat radius is lower than regular Mk1s?

[sankum]

The 10nos trainers of 83nos Tejas mk1a will be of common mk1 standard as the first 8nos trainers as per livefist report.
Extra trainer are ordered so that if mk2 is delayed 40 nos more single seater Tejas mk1a can be ordered to keep the production line running without restarting trainer line again.