Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

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Rakesh
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Rakesh »

John wrote:^ We don’t know capabilities of Rafale M operating from STOBAR Dassault has been very tight lipped about it ( quite a contrast to Boeing which has boasting F-18 capabilities operating from ski jump) ; Either they really have no idea or its payload capability is quite limited. So Rafale comparison might not be appropriate since we don't really know what it's capable of either.
John Saar, See This ----> viewtopic.php?f=3&t=7308&p=2349801#p2349801
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by JTull »

Our NLCA program will help device the specifications for ski jump and arrestor hook recovery by which Rafale-M and F-18E/F will be evaluated. IN won't take OEM word. It has learnt from Mig-29Ks which have severe deficiencies. There are fundamental structural issues which cannot be hidden after repeated take off and landings on ACs.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Kartik »

Image
While the Air force Version of Tejas has been the talk of town, the naval version continues with the flight test schedule leading to the ultimate goal. The common question has been on the date when is she going to land on deck. The effort required by the flight test crew even to attempt that is monumental, leave alone the development of the aircraft with the required technologies for that. The foremost thing one should keep in mind while being judgmental about the program is the difference between the two versions in terms of operation, operating envelope and the availability of required technology.
Jai Hind.
From LCA FB page
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Kartik »

Image
The Naval LCA continues to undergo the testing. Seen here is the NP-1 during one of the wave-off approach. The test pilots have to master that to achieve the desired sink rate to land on a deck. The task requires at least couple of hundreds of these approaches before the test pilots get and idea on how to achieve that.
From Tejas LCA FB page
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by ramana »

While the Air force Version of Tejas has been the talk of town, the naval version continues with the flight test schedule leading to the ultimate goal. The common question has been on the date when is she going to land on deck. The effort required by the flight test crew even to attempt that is monumental, leave alone the development of the aircraft with the required technologies for that. The foremost thing one should keep in mind while being judgmental about the program is the difference between the two versions in terms of operation, operating envelope and the availability of required technology.
Jai Hind.
Can some one decode this and how far along are they?
Is it TRL 2.0 or 5.0?

IOW are they ever going to do it and if so when?

Is it the designers or the test pilots who are wary?
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Kartik »

The way I see it- the N-LCA Mk1 still has the potential to become a good naval carrier fighter trainer. The Indian Navy could use it like the USN uses its Goshawks, with one key difference being that the N-LCA Mk1 is supersonic. Use the N-LCA Mk1 to learn and master the difficult skill of trapping a wire at INS Hansa's Shore Based Test Facility and then let those rookies practice it on a real carrier. A squadron of 18 such trainers would be a good way to bring in a dedicated supersonic carrier trainer whose operating costs will be much lower than either the MiG-29KUB or a Rafale M/Super Hornet twin seater.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Indranil »

Good point Kartik. As a trainer Mk1 is more than enough.

Ramana sir.
Earlier, they had got to within 1 m/sec of the desired sink rate with the fixed Levcon position. This last detachment, the Levcon was controlled by the pilots. They reached over half the sink rate desired. Every thing went really well. Now they are back in Bangalore to tweak the computer and allow higher sink rate.

This is really edgy stuff. Right at the pinnacle of aerodynamic control. Can't rush this. It is the capability to fly the aircraft accurately through a barn door. I am so jealous of people who get to do this.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by MeshaVishwas »

^^
Wow!
Pranaams to Team LCA.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by maitya »

Indranil wrote:<snip>
Earlier, they had got to within 1 m/sec of the desired sink rate with the fixed Levcon position. This last detachment, the Levcon was controlled by the pilots. They reached over half the sink rate desired. Every thing went really well. Now they are back in Bangalore to tweak the computer and allow higher sink rate.
<snip>
IIRC the, the aim/goal is to achieve 7.1 m/s sink rate - and 3.2m/s was achieved in SBTF in 2015-16 itself.

So in this detachment did they achieve ~6m/s sink rate is it?
Asking as, I think there's some typo in "They reached over half the sink rate desired" stmt - maybe Indranil wanted to say "... reached within half of a deg of the sink rate desired" etc. :twisted:
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by JayS »

I suppose usual sink rate for landing on a good day is ~3m/s while the LG is rated at max sink rate of 7.1m/s for hard landings especially in bad weather with deck pitching significantly. Achieving 7m/s sink rate at SBTF must be rather unnerving for the pilots as it would mean even steeper approach angle.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by chola »

JTull wrote:Our NLCA program will help device the specifications for ski jump and arrestor hook recovery by which Rafale-M and F-18E/F will be evaluated. IN won't take OEM word. It has learnt from Mig-29Ks which have severe deficiencies. There are fundamental structural issues which cannot be hidden after repeated take off and landings on ACs.
Big difference between the Rafale/F-18 and the MiG. We were the initial customer for the MiG-29K. We paid for the privilege of being guinea pigs. The Rafale M and F-18 especially are time-tested by other navies with many more cumulative takeoffs and landings from carriers than we could ever accumulate in the NLCA program. Of course, that data might never be passed on to us but I doubt we would see the kinds of deficiencies we saw/are seeing with the 29K.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Indranil »

Maitya ji,

You are right. I confused myself earlier. The goal is to get to 7.1 m/s. Actually, that is the max rate. At STBF, IIRC they are targeting 6.5 m/s. Right now they are at 75% of that value. Everything is going well. They will have to wait a little to go to full rate. At SBTF, the wind has to be in the right direction. It will happen before the end of this year for sure.

Kartik,
I heard your proposal is already a consideration within IN!
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by brar_w »

chola wrote:
JTull wrote:Our NLCA program will help device the specifications for ski jump and arrestor hook recovery by which Rafale-M and F-18E/F will be evaluated. IN won't take OEM word. It has learnt from Mig-29Ks which have severe deficiencies. There are fundamental structural issues which cannot be hidden after repeated take off and landings on ACs.
Big difference between the Rafale/F-18 and the MiG. We were the initial customer for the MiG-29K. We paid for the privilege of being guinea pigs. The Rafale M and F-18 especially are time-tested by other navies with many more cumulative takeoffs and landings from carriers than we could ever accumulate in the NLCA program. Of course, that data might never be passed on to us but I doubt we would see the kinds of deficiencies we saw/are seeing with the 29K.
During our trip aboard Enterprise (CVN 65) in April 1987, she took her 250,000th arrested landing, representing about a million individual settings...During heavy flight operations there may be anywhere from six hundred to a thousand settings of the engines in a single day. A typical deployment will have eight to ten thousand arrested landings ("traps"), involving thirty to forty thousand settings over a six-to-eight-month period.
https://fas.org/man/dod-101/sys/ship/docs/art7su98.htm

Using that as a baseline (and perhaps tweaking that down to say 6K landings given a smaller CAW) one can easily take the number of carrier deployments per year and get to an estimate of what a Hornet or Super Hornet number would be over the lifetime. Since the last decade or more the USN has been an all Hornet/SH fleet.

The Rafale is avaialble in relatively smaller quantities but even then the CDG does deploy and has a large number of deployments both during peacetime and conflict. Additionally, at least in the case of the SH, they have torn down aircraft that had reached their end of life to figure out and design a life extension program so quite a bit of data on lifetime durability is also available. Nothing remotely resembling real world testing was available on the MiG-29K as it was never put into service in any numbers over any prolonged extended deployments.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by sankum »

Indranil,
While landing the NLCA is on autotrottle just like Mig29k so that the pilot workload is reduced as he has to align the aircraft to just the centreline of runway and FCS takes care of the rest?
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by JTull »

Sea conditions matter too. I'm not sure how much automation of landing is possible.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Kartik »

Indranil wrote: Kartik,
I heard your proposal is already a consideration within IN!
Very glad to hear that all the effort that has been sunk into the program so far may likely bring about some really useful capability for the IN. the N-LCA Mk1 can emerge as the only dedicated supersonic carrier trainer in the world. All others are either twin seater variants of the fighter in service and far costlier to operate with greater maintenance requirements. Plus they use up valuable service life of the twin seaters (which are fully combat capable otherwise) in the training of rookies that could be easily handed to a trainer like the N-LCA Mk1.

Hope something positive emerges.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Indranil »

One exception. Nobody who lands on an AC is a rookie :wink:
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Indranil »

Sankum sirji,

Almost all modern deck landing aircrafts have that these days. The pilots focuses only on flight attitude to maintain glide path. The FC takes care of everything else.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by sankum »

Thanks Indranil ,Waiting for your article on NLCA mk2.
Understood that pilot input is on both axis. :rotfl:
Last edited by sankum on 22 May 2019 15:24, edited 1 time in total.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Kartik »

Indranil wrote:One exception. Nobody who lands on an AC is a rookie :wink:
I meant landings on the SBTF. Practiced till the rookie is qualified to do the same on the actual carrier. We were sending rookies to Kingsville in the US for training on Goshawks for carrier landing qualification. That entire training must now probably be done at INS Hansa itself with the MiG-29KUB. And that could be transferred to the N-LCA Mk1 trainer.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by JayS »

Indranil wrote:Sankum sirji,

Almost all modern deck landing aircrafts have that these days. The pilots focuses only on flight attitude to maintain glide path. The FC takes care of everything else.
For LCA at least, its the attitude i.e. AoA is what is controlled by Automatic AoA Hold Control AAHC, which is engaged once LG and Hook are down. Pilot controls the glide path through throttle control. Until there is no stick input, AAHC automatically holds AoA constant at optimum value. If Pilot gives stick input AAHC is disengaged and Pilot command is executed without any tweak in control law. Basically, up-down is controlled by Throttle. And I think, but I dont have confirmation, the left-right adjustment is still with stick.

F/A-18 are getting Magic carpet SW upgrade which simplifies the Carrier landing significantly. In this, they have designed Control laws in such a way that Stick forward-back gives no pitch but Aircraft up-down movement without pitch change. Stick become like a joystick for up-down, left-right adjustment of glide path.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by sankum »

Then NLCA is not on autothrottle like F18 magic carpet SW upgrade. May be in future SW upgrade is planned to give it autothrottle feature while landing. Though it is simple and safe with lighter load on pilot than older system with no such facility, the only drawback being that both hands of pilot will be tied down rather than one in with auto throttle feature.
Last edited by sankum on 23 May 2019 00:27, edited 1 time in total.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Indranil »

Jay,

Thanks for the correction.

Right now, they are evaluating/finalizing the "technique". Once that is fixed, throttle would be made automatic.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by JayS »

One step at a time.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by sankum »

Thanks JayS.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by JayS »

I was trying to find some details of Magic Carpet Control Law. It looks like prior to Magic carpet, F/A-18 had fully manual control of the glide slope, at least initially.
In a conventional carrier landing, the pilot follows an optical glideslope guidance from the
ship, with flaps deflected to a preset angle. If the aircraft descends
below the glideslope, the pilot has
to pull the stick back and pitch the
nose up to increase lift. This increases drag, so the pilot has to
add power to maintain speed, then
recover the original angle of attack
(alpha), and throttle back to avoid
over-speeding
Similarly, if the pilot wants to adjust the flight path towards left say, he would roll the jet towards left momentarily and then bing back the stick to centre again. But as Lift vector is tilted in this, there would be loss of altitude. The pilot would then have to adjust AoA to gain the altitude and for higher drag at higher AoA, he would also have to adjust throttle. Many many such small adjustments constantly for whole glide path and we are looking at some serious pilot work load.

I found mention of Direct lift control mode available for F/A-18 and F35C. So some work was done to reduce the pilot workload..

Compare this to Magic Carpet:
In a Magic Carpet approach,
the pilot can engage a “Delta
Path” law once the aircraft is on
the glideslope. The flight-control
system commands a reference
flightpath, in combination with pilot-entered ship speed, which corresponds to the optical signal from
the carrier. The aircraft will follow
this path automatically, with the
pilot correcting for any excursions.
A ship-relative velocity vector is
projected on the head-up display.
A major difference in the
Magic Carpet approach is that
the flaps are not fully deflected, and the flight control system uses them to add or reduce lift. If the aircraft falls below
the glideslope, the pilot still pulls
the stick back, but the control system deflects the flaps downward,
reducing descent rate at a constant alpha. Once the aircraft regains the glideslope, Magic Carpet
uses the flaps to readjust the vertical speed, again with no change
in alpha. The auto-throttle—which
on the Super Hornet is set to hold
a constant alpha at an airspeed
proportional to aircraft weight—will
make necessary adjustments.
Indranil is indicating that NLCA will have almost the same kind of automation level for Carrier Landing. Which would be at par with the state-of-the-art. Eventually we will have all the bells and whistles in the control system, including things like deck motion prediction and auto-correction of the Glide path accordingly, comparable to the best of the Naval figher in the world.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Rakesh »

Thank you JayS and Indranil for the above. This is awesome. You guys are fab! You made this jingo happy!!! :)
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by gaurav.p »

found this talk on magic carpet, might help. I think the magic carpet will also help in decreasing the structural stress on the ac and eventually leading to some increase in MTBFO. Hope it comes to fruition on the NLCA.



looking at bolter manoeuvres is scary itself.

Random idea = Is there is way to create a contraption on the tailhook which would warn the moment it realises that it will miss the last line. It will help in decreasing the reaction time for such bolter manoeuvres.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by JayS »

gaurav.p wrote:found this talk on magic carpet, might help. I think the magic carpet will also help in decreasing the structural stress on the ac and eventually leading to some increase in MTBFO. Hope it comes to fruition on the NLCA.



looking at bolter manoeuvres is scary itself.

Random idea = Is there is way to create a contraption on the tailhook which would warn the moment it realises that it will miss the last line. It will help in decreasing the reaction time for such bolter manoeuvres.
Ah. Thanks for the link. I was trying to locate this video. I had seen it a couple of years ago, but didnt bookmark it.

PS: Here is a nice, old USN training video which explains various operational factors that pilots need to keep in mind during carrier landing. This is from the days of A-8 which I suppose didn't have any automation of the landing, so all the basic flight characters are nicely explained. Good one to understand the nitty-gritty of carrier landing.

https://www.youtube.com/watch?v=SPlqoeaPUu4
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by Indranil »

The default assumption is that you are going to miss. They realize that they have trapped and make changes from bolter settings.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by MeshaVishwas »

Image
Image
With 2 of India's best; Naval Tejas & Navy test pilot Cmde Maolankar! Agile LCA matches best gen-4 fighters & is superb example of skills in design, flt testing & 'Make-in-India'. New govt MUST back LCA 100% & bring focus on a/c & engine design & production. We can match China.
https://twitter.com/arunp2810/status/11 ... 41513?s=19
Watershed event for Team LCA-N.
So happy to read this tweet from a legendary aviator.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by chola »

MeshaVishwas wrote: We can match China.
No, we don't want to match Cheen in this case. Their carrier fighter program had at least three crashes already.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by JayS »

MeshaVishwas wrote: https://twitter.com/arunp2810/status/11 ... 41513?s=19
Watershed event for Team LCA-N.
So happy to read this tweet from a legendary aviator.
He is been quite vocal in supporting NLCA.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by sajaym »

Recently while boarding a flight out of Goa Airport, I saw the NLCA takeoff from the runway and land back within 10 mins. While it was taking off and landing, other aircraft were waiting for it. I suppose the same thing happens the other way around too, when the NLCA has to wait for takeoff. Since the LCA has the HAL airport to itself, it doesn't face such a problem and testing can go on continuously.

That 10 min flight I saw might have been to check some minor setting. I guess dozens of such flights are required to test the NLCA till it becomes ready to starting testing on the carrier. But the problem is that while we have hundreds of airports and runways in our country, there is only one carrier! While it is afloat, the carrier has to perform it's regular duties as well. So how will the carrier be able to accommodate the testing of the NLCA also?

This brings me around to the view that we made a huge mistake with the INS Viraat while it was being retired. Instead of it being grouted (grounded, sealed to the seabed with concrete and moored) in Maharashtra, it could have been kept near the beach next to Goa Airport for easier and quicker testing cycle. Now I can only wonder what bike/scooter/cycle they will make after melting the Viraat.


https://economictimes.indiatimes.com/ne ... 474967.cms
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by yensoy »

There is a shore based test facility (SBTF) in Goa. It has its own "runway" to mimic a carrier. https://en.wikipedia.org/wiki/Shore_Based_Test_Facility
It's at the end of the southern taxiway, so shouldn't get in the way of normal taxiway movements; however as a precaution they might block active takeoff/landing during that time.

Goa is getting its own commercial airport at Mopa, freeing the current airport for exclusive Navy use. Google earth shows land being cleared for runway construction; actual status is probably a little further ahead.

Not dozens, hundreds of flights will be required to certify NLCA, as it should.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by sajaym »

X posting from the LCA pics thread...
gaurav.p wrote:drool over the LEVCONs.

Source

Image
The NLCA Mk1 will always be remembered for the LEVCONs. This device is a truly brilliant piece of innovation and I dare say it is India's own unique gift to the world of Naval Aviation. This thing looks like a canard, functions like a canard but after doing its function it goes back to being flush with the main wing thereby negating any impact on frontal RCS. Pranam to the designer who thought of this device.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by gaurav.p »

The NLCA Mk1 will always be remembered for the LEVCONs. This device is a truly brilliant piece of innovation and I dare say it is India's own unique gift to the world of Naval Aviation. This thing looks like a canard, functions like a canard but after doing its function it goes back to being flush with the main wing thereby negating any impact on frontal RCS. Pranam to the designer who thought of this device.
weren't LEVCONs first proposed in the Su-57?
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by JayS »

LEVCONs as a concept exists in Aero literature for decades. Nothing new. ADA might have proposed it for LCA ahead of Su57, not sure. But that doesn't really say much. Earliest reference to LEVCON I have found in any ADA publication is from 1995, IIRC.
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Re: Naval Tejas Mk1/Mk2: News & Discussion - 23 February 2019

Post by suryag »

Admiral Arun sir is retired when was this flight made ?
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