The HAL Tejas (Hindi pronunciation: [t�eːdʒəs]) is a lightweight multirole fighter developed by India. It is a

tailless,[N 1] compound delta-wing design powered by a single engine. It came from the Light Combat

Aircraft (LCA) programme, which began in the 1980s to replace India's ageing MiG-21 fighters. Later,

the LCA was officially named "Tejas",[4][N 2] meaning "Radiance" by then Prime Minister Atal Bihari

Vajpayee.[5]

The Tejas has a pure delta wing configuration, with no tailplanes or foreplanes, and a single dorsal fin. It

integrates technologies such as relaxed static stability, fly-by-wire flight control system, multi-mode radar,

integrated digital avionics system, composite material structures, and a flat rated engine.

The Tejas is the second supersonic fighter developed indigenously by Hindustan Aeronautics Limited

after the HAL Marut. The Indian Air Force (IAF) is reported to have a requirement for 200 single-seat and

20 two-seat conversion trainers, while the Indian Navy may order up to 40 single-seaters to replace itsSea Harrier FRS.51 and Harrier T.60.[6] The Tejas was cleared in January 2011 for use by Indian Air Force pilots. It is to reach final operational clearance in 2013.

[edit]Development

See also: Timeline of HAL Tejas

[edit]LCA programme

HAL Tejas at Aero India 2007

In 1969, the Indian government accepted the recommendation by its Aeronautics Committee

that Hindustan Aeronautics Limited (HAL) should design and develop an advanced technology fighter

aircraft around a proven engine. Based on a 'Tactical Air Support Aircraft' ASR markedly similar to that for

the Marut,[7] HAL completed design studies in 1975, but the project fell through due to inability to procure

the selected "proven engine" from a foreign manufacturer and the IAF's requirement for an air superiority

fighter with secondary air support and interdiction capability remained unfulfilled.[citation needed]

In 1983 IAF realized the need of an indigenous combat aircraft for two primary purposes. The principal

and most obvious goal was the development of a replacement aircraft for India's ageing MiG-21 fighters.

The MiG-21 has been the mainstay of the Indian Air Force since the 1970s. The "Long Term Re-

Equipment Plan 1981" noted that the MiG-21s would be approaching the end of their service lives by the

mid-1990s, and that by 1995 the IAF would lack 40% of the aircraft needed to fill its projected force

structure requirements.[8]

The LCA programme's other main objective was to serve as the vehicle for an across-the-board

advancement of India's domestic aerospace industry.[9] The value of the aerospace "self-reliance"

initiative is not simply the production of an aircraft, but also the building of a local industry capable of

creating state-of-the-art products with commercial spin-offs for a global market. The LCA program was

intended in part to further expand and advance India's indigenous aerospace capabilities.[10]

To better accomplish these goals, the government chose to take a different management approach, and

in 1984 established the Aeronautical Development Agency (ADA) to manage the LCA

programme.Although theTejas is most often described as a product of Hindustan Aeronautics

Limited (HAL), responsibility for the development of the Tejas actually belongs to ADA, a national

consortium of over 100 defence laboratories, industrial organisations, and academic institutions with HAL

being the principal contractor.[11]

The Indian government's "self-reliance" goals for the LCA include indigenous development of the three

most sophisticated — and hence most challenging — systems: the fly-by-wire (FBW) flight control

system(FCS), multi-mode pulse-doppler radar, and afterburning turbofan engine.[12] Although India has

had a policy of strictly limiting foreign participation in the LCA programme, these are the only major LCA

systems on which the ADA has had to invite significant foreign technological assistance and consultancy.

Moreover, the engine and radar are also the only major systems for which the ADA has seriously

considered substituting foreign equipment.[citation needed]

Of the five critical technologies the ADA identified at the beginning of the LCA programme as needing to

be mastered for India to be able to design and build a "completely indigenous" fighter, two have been

entirely successful: the development and manufacture of advanced carbon-fibre composite (CFC)

structures and skins and a modern "glass cockpit." In fact, ADA has had a profitable commercial spin-off

in its Autolay integrated automated software system for the design and development of 3-D laminated

composite elements (which has been licensed to both Airbus and Infosys).[12] These successes have gone

mostly unnoticed in the shadow of the problems encountered with the other three key technology

initiatives. Nonetheless, as a result of the accomplishments of India's domestic industries, presently about

70% of the components in LCA are manufactured in India and the dependence on imported components

used would be progressively reduced in the coming years.[13]

HAL serves as the prime contractor and has leading responsibility for LCA design, systems integration,

airframe manufacturing, aircraft final assembly, flight testing, and service support.[11] The ADA itself has

primary responsibility for the design and development of the LCA's avionics suite and its integration with

the flight controls, environmental controls, aircraft utilities systems management, stores management

system, etc.

HAL Tejas at Aero India 2009.

Of particular importance are the initiatives to develop an indigenous flight control system, radar, and

engine for the LCA. The National Aeronautics Laboratory (NAL)—now called the National Aerospace

Laboratories—was selected to lead the development of the flight control laws, supported by

the Aeronautical Development Establishment(ADE). HAL and the Electronics and Radar Development

Establishment (LRDE)[N 3] are jointly developing the Tejas' Multi-Mode Radar (MMR). The GTRE is

responsible for the design and parallel development of the GTX-35VS   Kaveri  afterburning turbofan engine

for the Tejas.

The IAF's Air Staff Requirement for the LCA were not finalised until October 1985. This delay rendered

moot the original schedule which called for first flight in April 1990 and service entry in 1995; however, it

also proved a boon as it is gave the ADA time to better marshal national R&D and industrial resources,

recruit personnel, create infrastructure, and to gain a clearer perspective of which advanced technologies

could be developed indigenously and which would need to be imported.[citation needed]

Project definition commenced in October 1987 and was completed in September 1988. Dassault

Aviation of France was hired as a consultant to review the PD and provide advice based on its extensive

aviation expertise. The PD phase is a critical early element in the aircraft design and development

process because from this flow key elements of the detailed design, manufacturing approach, and

maintenance requirements.[14]

The ambitiousness of the LCA programme in terms of pursuing self-reliance in aviation technologies is

illustrated by the fact that out of a total of 35 major avionics components and line-replaceable

units (LRUs), only three involve foreign systems. These are the multi-function displays (MFDs) by Sextant

(France) and Elbit (Israel), the helmet-mounted display and sight (HMDS) cueing system by Elbit, and the

laser pod supplied by Rafael (Israel). However, even among these three, when the LCA reaches the

production stage, the MFDs are expected to be supplied by Indian companies. A few other important

items of equipment (such as the Martin-Baker ejection seat) have been imported. As a consequence of

the embargo imposed on India after its nuclear weapons tests in May 1998, many items originally planned

to be imported were instead developed indigenously. The nuclear test sanctions delayed the development

of technologies that were already many years behind schedule.[14]

[edit]Development history

HAL Tejas parked next to F-16 Fighting Falcon and Eurofighter at 2009 Aero India.

The LCA design was finalised in 1990 as a small tail-less delta winged machine with relaxed static

stability (RSS) to enhance manoeuvrability performance. The sophisticated avionics and advanced

composite structure specified caused some concern almost immediately, and the IAF expressed doubt

that India possessed sufficient technological infrastructure to support such an ambitious project.[citation

needed] A governmental review committee was formed in May 1989 which reported out a general view that

Indian infrastructure, facilities and technology had advanced sufficiently in most areas to undertake the

project. As a measure of prudence, though, it was decided that the full-scale engineering development

(FSED) stage of the programme would proceed in two stages.[citation needed]

Phase 1 would focus on "proof of concept" and would comprise the design, development and testing

(DDT) of two technology demonstrator aircraft (TD-1 and TD-2) and fabrication of a structural test

specimen (STS) airframe; only after successful testing of the TD aircraft would the Indian government

give its full support to the LCA design. This would be followed by the production of two prototype vehicles

(PV-1 and PV-2), and creation of the necessary basic infrastructure and test facilities for the aircraft would

begin.[citation needed]

Phase 2 would consist of the manufacturing of three more prototype vehicles (PV-3 as the production

variant, PV-4 as the naval variant, and PV-5 as the trainer variant) and a fatigue test specimen, and the

construction of further development and test facilities at various work centres.[citation needed]

Phase 1 commenced in 1990 and HAL started work on the technology demonstrators in mid-1991;

however, a financial crunch resulted in full-scale funding not being authorised until April 1993, with

significant work on FSED Phase 1 commencing in June. The first technology demonstrator, TD-1, was

rolled out on 17 November 1995 and was followed by TD-2 in 1998, but they were kept grounded for

several years due to structural concerns and trouble with the development of the flight control system.[15]

One of the most ambitious requirements for the LCA was the specification that it would have "relaxed

static stability" (RSS). Although Dassault had offered an analogue FCS system in 1988, the ADA

recognised that digital flight control technology would soon supplant it.[12] RSS technology was introduced

in 1974 on the General Dynamics YF-16, which was the world's first production aircraft to be slightly

aerodynamically unstable by design. Most aircraft are designed with "positive" static stability, which

means they have a natural tendency to return to level and controlled flight in the absence of control

inputs; however, this quality tends to oppose the pilot's efforts to manoeuvre. An aircraft with "negative"

static stability (i.e., RSS), on the other hand, will quickly depart from level and controlled flight unless the

pilot constantly works to keep it in trim; while this enhances manoeuvrability, it is very wearing on a pilot

relying on a mechanical flight control system.[citation needed]

Development of a FBW flight control system requires extensive knowledge of flight control laws and the

expensive writing of a considerable amount of software code for the flight control computers, as well as its

integration with the avionics and other electronic systems. When the LCA programme was launched,

FBW was a state-of-the-art technology and such a sensitive one that India could find no nation willing to

export it. Therefore, in 1992 the LCA National Control Law (CLAW) team was set up by the National

Aeronautics Laboratory to develop India's own version.[citation needed] The CLAW team's scientists and

mathematicians were successful in developing their control laws, but could not test them since India did

not possess advanced real-time ground simulators at that time. Accordingly, British Aerospace (BAe)

and Lockheed Martin were brought in to help in 1993, but the effort required for the Aeronautical

Development Establishment to code the control laws into the FCS software proved a much larger job than

originally anticipated.[citation needed]

Specific control law problems were tested on BAE's simulators (and on HAL's, once theirs became

available). As it was being developed, progressive elements of the coding were checked out on the

"Minibird" and "Ironbird" test rigs at the ADE and HAL, respectively. A second series of inflight simulation

tests of the integrated flight control software were conducted on the F-16 VISTA (Variable In-flight

Stability Test Aircraft) simulator in the U.S. in July 1996, with 33 test flights being carried out. However,

Lockheed Martin's involvement was terminated in 1998 as part of an embargo enacted by the U.S. in

response to India's secondnuclear tests in May of that year.[citation needed]

The NAL's CLAW team eventually managed to successfully complete integration of the flight control laws

indigenously, with the FCS software performing flawlessly for over 50 hours of pilot testing on TD-1,

resulting in the aircraft being cleared for flight in early 2001. The LCA's maiden flight was made by TD-1

from National Flight Test Centre (NFTC), near Bangalore, on 4 January 2001, and its first successful

supersonic flight followed on 1 August 2003. TD-2 made its first flight on 6 June 2002. The automatic

flight control system (AFCS) of the Tejas has been highly praised by all of its test pilots, one of whom said

that he found it easier to take off with the LCA than in a Mirage 2000.[16]

Another critical technology area tackled for indigenous development by the ADA team is the Multi-Mode

Radar (MMR). It was initially planned for the LCA to use the Ericsson Microwave Systems PS-05/A I/J-

band multi-function radar,[17] which was developed by Ericsson and Ferranti Defence Systems

Integration for the Saab JAS-39   Gripen .[N 4] However, after examining other radars in the early 1990s,[N

5] the DRDO became confident that indigenous development was possible. HAL's Hyderabad division and

the LRDE were selected to jointly lead the MMR program and the radar development effort began in

1997.[19]

The DRDO's Centre for Airborne System (CABS) is responsible for running the test programme for the

MMR. Between 1996 and 1997, CABS converted the surviving HAL/HS-748M Airborne Surveillance Post

(ASP) testbed into a testbed for the avionics and radar of the LCA. Known as the 'Hack', the only major

structural modification besides the removal of the rotodome assembly was the addition of the LCA's nose

cone in order to accommodate the MMR.[citation needed]

By mid-2002, development of the MMR was reported to be experiencing major delays and cost

escalations. By early 2005 only the air-to-air look-up and look-down modes — two very basic modes —

were confirmed to have been successfully tested. In May 2006 it was revealed that the performance of

several modes being tested still "fell short of expectations."[20] As a result, the ADA was reduced to

running weaponisation tests with a weapon delivery pod, which is not a primary sensor, leaving critical

tests on hold. According to test reports, the crux of the problem is a serious compatibility issue between

the radar and the advanced signal processor module (SPM) built by the LRDE. Acquisition of an "off-the-

shelf" foreign radar is an interim option being seriously considered.[19][21][22]

[edit]Engine and propulsion

Initially, it was decided to equip the prototype aircraft with the General Electric F404-GE-

F2J3 afterburning turbofan engine. Simultaneously, in 1986, a parallel programme to develop an

indigenous powerplant was also launched. Led by the Gas Turbine Research Establishment, the GTRE

GTX-35VS, named "Kaveri", was expected to replace the F404 on all production aircraft. However,

progress in the Kaveri development programme was slowed by technical difficulties.

Development snags with the Kaveri resulted in the 2003 decision to procure the uprated F404-GE-IN20

engine for the eight pre-production LSP aircraft and two naval prototypes. General Electric was awarded

a US$105 million contract in 2004 for development engineering and production of 17 -IN20 engines,

delivery of which began in 2006. The F404-GE-IN20 was trial-installed on the Tejas and the engine

generated more than 19,000 pounds (85 kN) uninstalled thrust and completed 330 hours of Accelerated

Mission testing, equivalent of 1,000 hours of flight operation. In 2007, an additional 24 F404-IN20

afterburning engines were ordered to power the first operational squadron of Tejas fighters.[23]

In mid-2004, the Kaveri failed its high-altitude tests in Russia, ending the last hopes of introducing it with

the first production Tejas aircraft.[N 6] In February 2006, the ADA awarded a contract to the French aircraft

engine company Snecma for technical assistance in working out the Kaveri's problems.[6] The Kaveri

engine based on Snecma’s new core, an uprated derivative of the M88-2 engine that powers the French

Rafale fighter, providing 83–85 kilonewtons (kN) of maximum thrust was being considered a third option

by DRDO. This led the IAF to object that since Snecma had already developed the core of the engine, the

DRDO will not be participating in any joint development but merely providing Snecma with an indigenous

stamp.[24]

In 2008, it was announced that the Kaveri would not be ready in time for the Tejas, and that an in-

production powerplant would have to be selected[25] in the 95 to 100 kilonewton (kN) (21,000–23,000 lbf)

range to allow the aircraft to perform combat maneuvers with optimal weapons load. The contenders were

the Eurojet EJ200 and the General Electric F414.[26] IAF sources said that the airframe will have to be

redesigned to accommodate the heavier engine, which is to take up to three-four years.[27]

After evaluation and acceptance of the technical offer provided by both Eurojet and GE Aviation, the

commercial quotes were compared in detail and GE Aviation was declared as the lowest bidder. The deal

will cover purchase of 99 GE F414 engines. The initial batch will be supplied by GE and the remainder will

be manufactured in India under a transfer of technology arrangement.[28][29]

[edit]Recent development

Tejas trainer under construction

Tejas Trainer at 62nd Republic Day of India Parade, New Delhi

IAF Tejas Landing during Aero India 2013

In March 2005, the IAF placed an order for 20 aircraft, with a similar purchase of another 20 aircraft to

follow. All 40 will be equipped with the F404-GE-IN20 engine.[30][31][32]A 14 member "LCA Induction Team"

was formed at Bangalore to prepare the Tejas for service and assist with its induction into service.[33][34]

The first production variant of the Tejas (LSP-1) flew on June 2008. The Tejas completed 1,000 test

flights by January 2009 with more than 530 hours of inflight testing. By February 2009 officials of

the Aeronautical Development Agency stated that the Tejas had started flying with weapons and

integration of radars would be completed by March 2009. In addition, they stated that nearly all system

development activity would be completed by that time.[35] The Tejas achieved a speed of over 1,350

kilometres per hour (840 mph) during its sea level flight trials in 2009.[36]

In April 2010, the third production aircraft (LSP-3) flew with a hybrid version of the Elta EL/M-2032 multi-

mode radar,[37] and by June 2010, the fourth production aircraft took flight in the configuration it would be

delivered to the Indian Air Force in.[38]

By June 2010, the Tejas had also completed the second phase of hot weather trials. The objective of the

hot weather trials was to prove that the aircraft was in an IOC configuration with the weapon system and

sensors integrated.[39] The sea trials of the aircraft are also being carried out.[40] LSP-5 with IOC standard

equipment took to skies on 19 November 2010.[41]

The trainer variant prototype took to the skies in November 2009.[42] In December 2009, the Indian

government sanctioned  8,000 crore (US$1.46 billion) to begin production of the fighter jet for the Indian

Air Force and Indian Navy. The Indian Navy has a requirement of 50 Tejas aircraft and the first prototype,

NP-1 was rolled out in July 2010.[43]IAF ordered 20 additional Tejas fighters after the defence acquisition

council cleared the plan.[44]

In November 2010, it was reported that the Tejas Mk1 reportedly fell short of the relaxed Air Staff

Requirements stipulated for limited series production (LSP) aircraft. The areas that did not meet

requirements were power to weight ratio, sustained turning rate, maximum speeds at low altitudes, AoA

range, and weapon delivery profiles. The extent of the deficiencies was classified.[45]

Initial Operating Clearance (IOC) for the Tejas was awarded on 10 January 2011 by Defence Minister A K

Antony to Chief of Air Staff Air Chief Marshal P V Naik. IOC allows IAF pilots to use the aircraft.

The IAF plans to raise the first squadron in Bengaluru to iron out issues with ADA and HAL, and

eventually base these fighters at Sulur Air Force Base, Coimbatore in the southern state of Tamil Nadu.

The first squadron is expected to be established by 2013.[31][32][46][47]

The IAF officially accepted its first Tejas fighter on 21 March 2011. The Tejas is planned to be cleared for

operational service by late 2012. The weapon tests including bombing begun in September 2011 at

Pokhran range, to be followed by missile firing tests at Goa.[48]

Tejas' Final Operational Clearance (FOC) has reportedly been delayed until mid-2013 or later.[49]

[50] The Tejas program has enlisted EADS to help expand the flight envelope to meet service

requirements.[51] RAFAEL’s Derby fire-and-forget missile will serve as the Tejas’ initial medium range air-

air armament.[52]

The Tejas has completed 1,828 test flights by 16 April 2012.[53] The Naval LCA made its first flight, almost

two years after being rolled out, on 27 April 2012.[54]

On 27 June 2012, three HAL Tejas (LSP 2, 3 and 5) completed precision bombing runs in the desert of

Rajasthan, where they deployed a series of weapons, including laser-guided 1000-lbs bombs and

unguided bombs. The LCA had conducted similar bombing runs in the month of September 2011 at

Pokhran.[55] The Tejas has completed almost 2,000 flights by July 2012. Some defence sources indicate

that it will not reach final operational clearance (FOC) and become fully combat capable until 2015.[56]

The Tejas was grounded for over three months because of the new pilot’s helmets extended above the

ejection seats. The helmets could have prevented a smooth ejection by hitting the canopy before it was

blown off. This represented a serious safety issue and flight testing was stopped in August 2012. The

ejection systems have been modified to rectify this issue. Flight tests resumed in November with seven

successfully completed.[57]

LSP 8 is ready for flight trials after recent ground tests [58]

[edit]Design

[edit]Overview

PV-3 in Indian Air Force grey camouflage pattern

The Tejas is single-engined multirole fighter which features a tailless, compound delta planform and is

designed with "relaxed static stability" for enhanced manoeuvrability. Originally intended to serve as an air

superiority aircraft with a secondary "dumb bomb" ground-attack role, the flexibility of this design

approach has permitted a variety of guided air-to-surface and anti-shipping weapons to be integrated for

more well-rounded multirole and multimission capabilities.[citation needed]

The tailless, compound-delta planform is designed to keep the Tejas small and lightweight.[59] The use of

this platform also minimises the control surfaces needed (notailplanes or foreplanes, just a single vertical

tailfin), permits carriage of a wider range of external stores, and confers better close-combat, high-speed,

and high-alphaperformance characteristics than comparable cruciform-wing designs. Extensive wind

tunnel testing on scale models and complex computational fluid dynamics analyses have optimised the

aerodynamic configuration of the LCA, giving it minimum supersonic drag, a low wing-loading, and high

rates of roll and pitch.[citation needed]

All weapons are carried on one or more of seven hardpoints with total capacity of greater than 4,000 kg:

three stations under each wing and one on the under-fuselagecentreline. There is also an eighth, offset

station beneath the port-side intake trunk which can carry a variety of pods (FLIR, IRST, laser

rangefinder/designator, orreconnaissance), as can the centreline under-fuselage station and inboard pairs

of wing stations.[citation needed]

The Tejas has integral internal fuel tanks to carry 3,000 kg of fuel in the fuselage and wing, and a

fixed inflight refuelling probe on the starboard side of the forward fuselage. Externally, there are "wet"

hardpoint provisions for up to three 1,200- or five 800-litre (320- or 210-US gallon; 260- or 180-Imp gallon)

fuel tanks on the inboard and mid-board wing stations and the centreline fuselage station.[citation needed]

[edit]Airframe

Composites in the LCA

The LCA is constructed of aluminium-lithium alloys, carbon-fibre composites (C-FC), and titanium-alloy

steels. The Tejas employs C-FC materials for up to 45% of its airframe by weight, including in

the fuselage (doors and skins), wings (skin, spars and ribs), elevons, tailfin, rudder, air

brakes and landing gear doors. Composites are used to make an aircraft both lighter and stronger at the

same time compared to an all-metal design, and the LCA's percentage employment of C-FCs is one of

the highest among contemporary aircraft of its class.[60] Apart from making the plane much lighter, there

are also fewer joints or rivets, which increases the aircraft's reliability and lowers its susceptibility to

structural fatigue cracks.[citation needed]

The tailfin for the LCA is a monolithic honeycomb piece, an approach which reduced its manufacturing

cost by 80% compared to the customary "subtractive" or "deductive" method, whereby the shaft is carved

out of a block of titanium alloy by a computerised numerically controlled machine. No other manufacturer

is known to have made fins out of a single piece.[61] A "nose" for the rudder is added by "squeeze" riveting.[citation needed]

Tejas at Aero-India 09

The use of composites in the LCA resulted in a 40% reduction in the total number of parts compared to

using a metallic frame. Furthermore, the number of fasteners has been reduced by half in the composite

structure from the 10,000 that would have been required in a metallic frame design. The composite

design also helped to avoid about 2,000 holes being drilled into the airframe. Overall, the aircraft's weight

is lowered by 21%. While each of these factors can reduce production costs, an additional benefit — and

significant cost savings — is realised in the shorter time required to assemble the aircraft — seven

months for the LCA as opposed to 11 months using an all-metal airframe.[62]

The airframe of the naval variant of the Tejas will be modified with a nose droop to provide improved view

during landing approach, and wing leading edge vortex controllers(LEVCON) to increase lift during

approach. The LEVCONs are control surfaces that extend from the wing-root leading edge and thus

afford better low-speed handling for the LCA, which would otherwise be slightly hampered due to the

increased drag that results from its delta-wing design. As an added benefit, the LEVCONs will also

increase controllability at high angles of attack (AoA).[citation needed]

The naval Tejas will also have a strengthened spine, a longer and stronger undercarriage, and powered

nose wheel steering for deck manoeuvrability.[63][64] The Tejastrainer variant will have "aerodynamic

commonality" with the two-seat naval aircraft design.[65]

[edit]Landing gear

Hydraulically retractable tricycle-typelanding gear

The Tejas has a hydraulically retractable tricycle-type landing gear with a pair of single inward-retracting

mainwheels and a steerable, twin-wheel forward-retracting nose gear. The landing gear was originally to

have been imported, but following the imposition of trade sanctions, HAL developed the entire system

independently.[citation needed]

[edit]Flight controls

The HAL Tejas conducting an inverted pass shown here is an example of fly-by-wire controls.

Since the Tejas is a relaxed static stability design, it is equipped with a quadruplex digital fly-by-wire flight

control system to ease handling by the pilot.[66] The Tejas aerodynamic configuration is based on a pure

delta-wing layout with shoulder-mountedwings. Its control surfaces are all hydraulically actuated. The

wing's outer leading edge incorporates three-section slats, while the inboard sections have additional

slats to generate vortex lift over the inner wing and high-energy air-flow along the tail fin to enhance high-

AoA stability and prevent departure from controlled flight. The wing trailing edge is occupied by two-

segmentelevons to provide pitch and roll control. The only empennage-mounted control surfaces are the

single-piece rudder and twoairbrakes located in the upper rear part of the fuselage, one each on either

side of the fin.[citation needed]

The digital FBW system of the Tejas employs a powerful digital flight control computer (DFCC) made by

Aeronautical Development Establishment (ADE) comprising four computing channels, each with its own

independent power supply and all housed in a single LRU. The DFCC receives signals from a variety of

sensors and pilot control stick inputs, and processes these through the appropriate channels to excite and

control the elevons, rudder and leading edge slat hydraulic actuators. The DFCC channels are built

around 32-bit microprocessors and use a subset of the Ada programming language for software

implementation. The computer interfaces with pilot display elements like the MFDs through MIL-STD-

1553B multiplex avionics data buses and RS-422 serial links.[citation needed]

[edit]Propulsion

General Electric F404-IN20 engine for the eight pre-production LSP aircraft and two naval prototypes

The wing-shielded, side-mounted bifurcated, fixed-geometry Y-duct air intakes have an optimised diverter

configuration to ensure buzz-free air supply to the engine at acceptable distortion levels, even at high

AoA.[citation needed]

The original plan was for the LCA prototype aircraft to be equipped with the General Electric F404-GE-

F2J3 afterburning turbofan engine, while the production aircraft would be fitted with the indigenous GTRE

GTX-35VS   Kaveri  turbofan being developed in a parallel.[citation needed] Continued development snags with

the Kaveri resulted in a 2003 decision to procure the upgraded GE F404-IN20 engine for the eight pre-

production LSP aircraft and two naval prototypes and after accelerated trials an order was placed for 24

more IN20 engines for installation on the first 20 production aircraft. The Tejas Mark II will be equipped

with the more powerful GE F414 engine.[citation needed]

[edit]Avionics

The Tejas has a night vision goggles (NVG)-compatible "glass cockpit" that is dominated by an CSIR-

CSIO developed indigenous head-up display (HUD), three 5 in x 5 in multi-function displays, two Smart

Standby Display Units (SSDU), and a "get-you-home" panel providing the pilot with essential flight

information in case of an emergency. The CSIO-developed HUD, Elbit-furnished DASH helmet-mounted

display and sight (HMDS), and hands-on-throttle-and-stick (HOTAS) controls reduce pilot workload and

increase situation awareness by allowing the pilot to access navigation and weapon-aiming information

with minimal need to spend time "head down" in the cockpit.[citation needed] Navigation is via both GPS and an

inertial navigation system. Instrument Landing System (ILS) is used for landing in poor weather. The

aircraft also features a ground proximity warning system based on the Terrain Referenced Navigation

(TRN) system. Threat detection methods include a Radar Warning Receiver (RWR). Missile Approach

Warning (MAW) and a Laser Warning Receiver (LWR). Protection is provided by Chaff, Jaff and Flares,

Electronic Counter Measures (ECM) and a Towed Radar Decoy (TRD). DVI system utilises a speech

recognition module.[citation needed]

The multi-function displays provide information on the engine, hydraulics, electrical, flight control, and

environmental control systems on a need-to-know basis, along with basic flight and tactical information.

Dual redundant display processors produce computer-generated imagery on these displays. The pilot

interacts with the complex avionics systems through a simple multifunction keyboard and function and

sensor selection panels.[citation needed]

Target acquisition is accomplished through a state-of-the-art radar and is potentially supplemented by

a laser designator pod Forward looking infrared (FLIR) or other opto-electronic sensors. This provides

accurate target information to enhance kill probabilities.GPS and a ring laser gyro based inertial

navigation system provides accurate navigation guidance to the pilot.[citation needed] The LCA also has secure

and jam-resistant communication systems such as the IFF transponder/interrogator, VHF/UHF radios,

and air-to-air/air-to-ground datalinks. The ADA Systems Directorate's Integrated Digital Avionics Suite

(IDAS) integrates the flight controls, environmental controls, aircraft utilities systems management, stores

management system (SMS), etc. on three 1553B buses by a centralised 32-bit, high-throughput mission

computer.[citation needed]

[edit]Radar

The coherent pulse-Doppler Multi-Mode Radar in development is designed to keep track of a maximum of

10 targets and allows simultaneous multiple-target engagement. Jointly developed by the LRDE and HAL

Hyderabad, the MMR is being designed to perform multi-target search, track-while-scan (TWS), and

ground-mapping functions.[citation needed] It features look-up/look-down modes, low/medium/high pulse

repetition frequencies (PRF), platform motion compensation, doppler beam-sharpening, moving target

indication (MTI), Doppler filtering, constant false alarm rate (CFAR) detection, range-Doppler ambiguity

resolution, scan conversion, and online diagnostics to identify faulty processor modules.[citation needed]

While originally planned to be fitted on production aircraft, delays in the development of MMR prompted

the DRDO to co-operate with Israel Aerospace Industries to integrate a Hybrid version of the EL/M-

2032 radar for use with the Tejas.[37] The EL/M-2032 radar used in LSP-3 has a detection and tracking

range of up to 150 km in air-to-air mode, the air-to-ground mode generates high resolution radar imagery

of locations at up to 150 km, and air-to-sea mode can detect and classify naval targets at ranges of up to

300 km.Another track System is an infrared search and track system (IRST)[67]

The development of an AESA radar for the Tejas is expected to begin pending the selection of a

developmental partner. The contenders for the contract are the European Consortium EADS and the

Israel's Elta. The initial contract will see the co-development of 10 prototypes.[68]

[edit]Self-protection

The electronic warfare suite is designed to enhance the survivability during deep penetration and combat.

The LCA's EW suite is developed by the Defence Avionics Research Establishment (DARE) with support

from the Defence Electronics Research Laboratory (DLRL). This EW suite, known as Mayavi, includes

a radar warning receiver (RWR), Missile Approach Warning (MAW) and a Laser warning receiver (LWR)

system, self-protection jammer, laser warning system, and chaff/flare dispenser. In the interim, the Indian

Ministry of Defense has revealed that an unspecified number of EW suites had been purchased from

Israel's Elisra for the LCA prototypes.[69]

The ADA claims that a degree of stealth has been designed into the Tejas. Being very small, there is an

inherent degree of visual stealth, but the airframe's use of a high degree of composites (which do not

reflect radar waves), a Y-duct inlet which shields the engine compressor face from probing radar waves,

and the application of radar-absorbent material (RAM) coatings are intended to minimise its susceptibility

to detection and tracking by the radars of enemy fighters.[citation needed]

[edit]Escape systems

Although two-seat variants of the LCA are planned, the examples built to date are crewed by a single pilot

on a Martin-Baker zero-zero ejection seat. The British Martin-Baker ejection seat is planned to be

replaced with a locally developed alternative.[70] To improve pilot safety during ejection, the Armament

Research and Development Establishment (ARDE) created a new line-charged canopy severance

system, which has been certified by Martin-Baker.[citation needed]

[edit]Flight simulator

To support the aircraft, a dome-based mission simulator has been developed by the Aeronautical

Development Establishment (ADE), Bangalore. It has been used to provide design support during the

initial phase of LCA development, in particular handling quality evaluation and planning and practising

mission profiles.[citation needed]

[edit]Operational history

The work to raise the first squadron started in July 2011. The Tejas will be inducted into the 45th

squadron, the Flying Daggers and will be based in Bangalore before being moved to Sulur.[71]

According to the Director General of the DRDO V. K. Saraswat, HAL Tejas is to be inducted into

the Indian Air Force in 2012.[72]

[edit]Variants

[edit]Prototypes

Aircraft already built and projected models to be built. Model designations, tail numbers and dates of first

flight are shown.

Technology Demonstrators (TD)

TD-1 (KH2001) – 4 Jan 2001

TD-2 (KH2002) – 6 June 2002

Prototype Vehicles (PV)

PV-1 (KH2003) – 25 November 2003

PV-2 (KH2004) – 1 December 2005

PV-3 (KH2005) – 1 December 2006. This is the production variant.

PV-4

PV-5 (KH-T2009) – 26 November 2009 – Fighter/Trainer Variant

Naval Prototypes (NP)

NP-1 – Two-seat Naval variant for carrier operations. Rolled out in July 2010.[73] It was planned to

make first flight by mid-July 2011.[74] NP-1 made its first flight on 27 April 2012.[54]

NP-2 – Single-seat LCA MK 1 Naval variant for carrier operations. Both NP-1 & NP-2 are

powered by GE-404 engine. NP-2 is in advanced stage of completion and is expected to fly by end of

2012.[54]

NP-3 & NP-4 – Single-seat LCA MK 2 Naval variant for carrier operations to be powered by the

GE-414 engines. The design work on the two aircraft is nearly complete.[54]

NP-5 – Another Single-seat LCA MK 1 Naval variant is planned so as to enhance the pace of

certification process for Naval LCA.[54]

Limited Series Production (LSP) aircraft

Currently, 8 LSP series aircraft plus 40 aircraft are on order.

LSP-1 (KH2011) – 25 April 2007. This LCA is powered by F404-F2J3 Engine.[75]

LSP-2 (KH2012) – 16 June 2008. This is the first LCA fitted with F404-IN20 engine.[75]

LSP-3 23 April 2010. The first aircraft to have the Hybrid MMR radar[37] and will be close to the

IOC standard.

LSP-4 (KH2014) – 2 June 2010. The first aircraft that was flown in the configuration that will be

delivered to the Indian Air Force.[38] In addition to the Hybrid MMR, the aircraft flew with

a CountermeasureDispensing System and an identify friend or foe electronic system.[76]

LSP-5 (KH2015) – 19 November 2010. IOC standard, with all sensors including night lighting in

the cockpit, and an auto-pilot.[77]

LSP-6 – Will be used to increase the Angle of Attack.[78] As well as develop better (Experimental)

RAM coating to further reduce its radar signature.[74]

LSP-7 (KH2017) – 9 March 2012. APU intake has been aerodynamically reshaped.

LSP-8 – Ground tests completed and is ready for user trials.[58]

SP-1 to SP-40 – Planned to fly by late 2013. The SP-1 and SP-2 were to be delivered by March

2012 and handed over to No. 45 Squadron (Flying Daggers) that will be based initially in Bangalore,

Karnataka.[74]

[edit]Planned production variants

Tejas Trainer – Two-seat operational conversion trainer for the Indian Air Force.

Tejas Navy – Twin- and single-seat carrier-capable variants for the Indian Navy. The LCA's naval

variant is to be ready for carrier trials by 2013 and is slated for deployment on the INS

Vikramaditya as well as theVikrant class aircraft carrier.[79] It will be equipped for carrier operation with

ski-jump take-off and arrested landing. It will include strengthened airframe and landing gear and the

nose is drooped for better cockpit vision.[80]

[edit]Tejas Mark 2

Featuring the more powerful General Electric F414-GE-INS6 engine with 98 kN of thrust and refined

aerodynamics, the Mark 2 is being developed to meet the Indian Air Force requirements and will

incorporate 5th generation fighter elements which are intended to make way into the FGFA and AMCA.

The Tejas Mk 2 will now have a length of 14.2 metres (1-metre more than that of the Tejas Mk 1, for

incorporating a stretched nose section and a modified fuselage section aft of the cockpit for housing an

expanded complement of mission avionics LRUs), height of 4.6 metres (as opposed to 4.4 metres of

the Tejas Mk 1, to accommodate an enlarged vertical tail-section) and a wingspan of 8.2 metres, same as

that of the Tejas Mk 1, that, however with an increased wing area. External stores capacity will be

boosted to 5,000 kg (as opposed to 4,000 kg for the Tejas Mk1), while the twin internal air-intake ducts

will be minimally enlarged to cater to the increased airflow requirements of the 98 kN thrust F414-GE-

INS6 turbofan built by GE Aero Engines. The Ministry of Defence had, last January, sanctioned

US$542.44 million (Rs2,431.55-crore) for ADA to develop the IAF’s Tejas Mk 2 variant and the Indian

Navy’s LCA Mk 2 (Navy) variant. The first Tejas Mk 2 prototype will fly by December 2013. The IAF is

committed to procuring an initial 83 Tejas Mk 2s and the Indian Navy has expressed its firm requirement

for 46 LCA Mk2 (Navy).[30][81][82]

[edit]Operators

 India

Indian Air Force  – 40 LCA Mk 1 aircraft on order. Plans to order LCA Mk 2 aircraft for 10 more

squadrons (about 180 total aircraft) after completing production of LCA Mk 1.[83][84]

Indian Navy  – Signed an order for six Naval LCAs at an approximate cost of US$ 31.09 million

per aircraft.[3] The Indian Navy has a requirement for 50 Tejas aircraft.[43]

[edit]Specifications (HAL Tejas Mk.1)

Data from tejas.gov.in[85] DRDO Techfocus,[86] Aero India 2011,[87]

General characteristics

Crew: 1

Length: 13.20 m (43 ft 4 in)

Wingspan : 8.20 m (26 ft 11 in)

Height: 4.40 m (14 ft 9 in)

Wing area: 38.4 m² (413 ft²)

Empty weight : 6,500 kg (14,300 lb)

Loaded weight: 9,500 kg (20,944 lb)

Max. takeoff weight : 13,300 kg (29,100 lb)

Powerplant : 1 × F404-GE-IN20 turbofan

Dry thrust: 53.9 kN[88] (12,100 lbf)

Thrust with afterburner: 85 kN[89][90][91] (19,000 lbf)

Internal fuel capacity: 2,458 kg

External fuel capacity: 2 x 1,200 litre drop tank at inboard, 1 x 725-litre drop tank under fuselage

Performance

Maximum speed : Mach 1.6[85] (1,350 km/h) ; (CAS) at high altitude

Range : 850 km[citation needed] (530 mi) without refuelling

Combat radius : 300 km[citation needed] (186 miles)

Ferry range : 3,000 km[92] (1,840 mi)

Service ceiling : 15,250 m[93] (50,000 ft)

Wing loading : 247 kg/m² (50.7 lb/ft²)

Thrust/weight : 1.07[85]

g-limits: +8/−3.5 g[85]

Armament

Guns: 1× mounted 23 mm twin-barrel GSh-23 cannon with 220 rounds of ammunition.

Hardpoints : 8 total: 1× beneath the port-side intake trunk for targeting pods, 6× under-wing, and

1× under-fuselage with a capacity of 4,000 kg external fuel and ordnance

Missiles:

HAL Tejas carrying R-73 missile and Drop Tank.

Tejas weapon display Aero India 2011

Air-to-air missiles :

Python 5

Derby [97]

Astra  Beyond Visual Range missile

Vympel R-77

Vympel R-73

Air-to-surface missiles :

Kh-59 ME (TV guided standoff Missile)

Kh-59 MK (Laser guided standoff Missile)

Anti-ship missiles

Kh-35

Kh-31

Bombs:[94]

KAB-1500L laser-guided bombs

GBU-16 Paveway II

FAB-250

ODAB-500PM fuel-air explosives

ZAB-250/350 incendiary bombs

BetAB-500Shp powered concrete-piercing bombs

FAB-500T dumb bombs

OFAB-250-270 dumb bombs

OFAB-100-120 dumb bombs

RBK-500 cluster bomb stake

Others:[94]

S-8 rocket pods

Bofors 135 mm rocket

Drop tanks  for ferry flight/extended range/loitering time.

LITENING targeting pod