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Tejas
HAL Tejas
Role Multirole fighter
National origin India
Manufacturer Hindustan Aeronautics Limited (HAL)
Designer Aeronautical Development Agency
First flight 4 January 2001
Status In production
Primary users Indian Air Force
Indian Navy
Number built 13 (prototypes and LSP aircraft)[1]
Program cost US$1.2 billion[2]
Unit cost
US$31 million[3]
US$31.09 million (Naval version)[4]

The HAL Tejas (Hindi pronunciation: [t̪eːdʒəs] Hindi:तेजस) is a multirole light 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",[5][N 2] meaning "Radiance" by then Prime Minister Atal Bihari Vajpayee.[6]

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 (HAL) 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 its Sea Harrier FRS.51 and Harrier T.60.[7] The Tejas was cleared in January 2011 for use by Indian Air Force pilots. It is to reach the second of three levels of operational clearance in November 2013.[8]

Development[]

LCA programme[]

Hindustan LCA Tejas Krivchikov 2007

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,[9]

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-21fighters. 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.[10]

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.[11] 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.[12]

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 the Tejas 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.[13]

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.[14]

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).[14] 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.[15]

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.[13] 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 AeroIndia-2009

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.

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.[16]

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.[16]

Development history[]

HAL tejas,F-16,Eurofighter Typhoon

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.[17]

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.[14] 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 second nuclear tests in May of that year.[18]

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.[19]

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,[20] which was developed by Ericsson and Ferranti Defence Systems Integration for the Saab JAS-39Gripen.[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.[22]

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.[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."[23] 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.[22][24][25]

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.[26]

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.[7] 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.[27]

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[28] 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.[29] 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.[30]

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.[31][32]

Recent developments[]

HAL Tejas trainer version construction

Tejas trainer under construction

Tejas Trainer 62 New Delhi Parade

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

IAF Tejas Landing at Aero India 2013

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.[33][34][35] A 14 member "LCA Induction Team" was formed at Bangalore to prepare the Tejas for service and assist with its induction into service.[36][37]

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.[38] The Tejas achieved a speed of over 1,350 kilometres per hour (840 mph) during its sea level flight trials in 2009.[39]

In April 2010, the third production aircraft (LSP-3) flew with a hybrid version of the Elta EL/M-2032multi-mode radar,[40] and by June 2010, the fourth production aircraft took flight in the configuration it would be delivered to the Indian Air Force in.[41]

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.[42] The sea trials of the aircraft are also being carried out.[43] LSP-5 with IOC standard equipment took to skies on 19 November 2010.[44]

The trainer variant prototype took to the skies in November 2009.[45] In December 2009, the Indian government sanctioned INR8000 (US$1.3 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.[46] IAF ordered 20 additional Tejas fighters after the defence acquisition council cleared the plan.[47]

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.[48]

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.[34][35][49][50]

The weapon tests including bombing begun in September 2011 at Pokhran range, to be followed by missile firing tests at Goa.[51] RAFAEL’s Derby fire-and-forget missile will serve as the Tejas’ initial medium range air-air armament.[52]

Tejas' Final Operational Clearance (FOC) was reportedly delayed from December 2012 until mid-2013 or later.[53][54] The Tejas program has enlisted EADS to help expand the flight envelope to meet service requirements.[55]

The Naval LCA made its first flight, almost two years after being rolled out, on 27 April 2012.[56]

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 1,000 lb bombs and unguided bombs. The LCA had conducted similar bombing runs in the month of September 2011 at Pokhran.[57] The Tejas has completed 1,941 flights by July 2012.[58] Some defence sources indicate that it will not reach FOC and become fully combat capable until 2015.[59]

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.[60] LSP 8 had a successful maiden test flight on 31 March 2013 at Bangalore.[1] Tejas has completed 2,380 test flights by 30 October 2013.[61]

HAL has been instructed by the Indian government to strictly adhere to deadlines to ensure IOC-2 by end of 2013 and Final Operational Clearance (FOC) by the end of 2014. Tejas will be inducted after IOC-2.[62]

Design[]

Overview[]

Tejas air force grey

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.[63] The use of this platform also minimises the control surfaces needed (no tailplanes 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-alpha performance characteristics than comparable cruciform-wing designs.[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-fuselage centreline. An eighth offset station beneath the port-side intake trunk can carry a variety of pods like FLIR, IRST, laser rangefinder/designator for reconnaissance or training, as can the centreline under-fuselage station and inboard pairs of wing stations.[18][64][65]

Airframe[]

LCA Composites

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.[66]

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.[67]

AeroIndia-09 HAL Tejas

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.[68]

The naval Tejas will also have a strengthened spine, a longer and stronger undercarriage, and powered nose wheel steering for deck manoeuvrability.[69][70] The Tejas trainer variant will have "aerodynamic commonality" with the two-seat naval aircraft design.[71]

Flight controls[]

Tejas inverted pass

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.[72] The Tejas aerodynamic configuration is based on a pure delta-wing layout with shoulder-mounted wings. 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-segment elevons to provide pitch and roll control. The only empennage-mounted control surfaces are the single-piece rudder and two airbrakes located in the upper rear part of the fuselage, one each on either side of the fin.[citation needed]

Propulsion[]

GE F404 engine

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]

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]

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.[18] This provides accurate target information to enhance kill probabilities. GPS and a ring laser gyro basedinertial navigation system provides accurate navigation guidance to the pilot.[64][65] The LCA also has secure and jam-resistant communication systems such as the IFF transponder/interrogator, VHF/ 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.[64]

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]

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-2032radar for use with the Tejas.[40] 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)[73]

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.[74]

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.[75]

The ADA claims that a degree of stealth has been designed into the Tejas.[citation needed]

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.[76]

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.[77]

Variants[]

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.[78] NP-1 made its first flight on 27 April 2012.[56]
  • NP-2 – Single-seat LCA MK 1 Naval variant for carrier operations. Both NP-1 & NP-2 are powered by GE-404 engine.[56]
  • 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.[56]
  • NP-5 – Another Single-seat LCA MK 1 Naval variant is planned so as to enhance the pace of certification process for Naval LCA.[56]
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.[79]
  • LSP-2 (KH2012) – 16 June 2008. This is the first LCA fitted with F404-IN20 engine.[79]
  • LSP-3 23 April 2010. The first aircraft to have the Hybrid MMR radar[40] 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.[41] In addition to the Hybrid MMR, the aircraft flew with a Countermeasure Dispensing System and an identify friend or foe electronic system.[80]
  • LSP-5 (KH2015) – 19 November 2010. IOC standard, with all sensors including night lighting in the cockpit, and an auto-pilot.[81]
  • LSP-6 – Will be used to increase the Angle of Attack.[82] As well as develop better (Experimental) RAM coating to further reduce its radar signature.[83]
  • LSP-7 (KH2017) – 9 March 2012. APU intake has been aerodynamically reshaped.
  • LSP-8 – First flight trial completed in March 2013. LSP 8 is the version that will go for production.[1]
  • SP-1 to SP-40 – Planned to fly by late 2013. The SP-1 and SP-2 will be part of No. 45 Squadron (Flying Daggers) that will be based initially in Bangalore, Karnataka.[83]

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 the Vikrant class aircraft carrier.[84] 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.[85]

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 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).[33][86][87]

Operators[]

Flag of India 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.[88][89]
  • Indian Navy – Signed an order for six Naval LCAs at an approximate cost of US$31.09 million per aircraft.[4] The Indian Navy has a requirement for 50 Tejas aircraft.[46]

Specifications (HAL Tejas Mk.1)[]

Data from tejas.gov.in[90] DRDO Techfocus,[91] Aero India 2011,[92]

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[93] (12,100 lbf)
    • Thrust with afterburner: 85 kN[94][95][96] (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 1.8[97] (1,920 km/h) ; (CAS) at high altitude
  • Range: 850 km[98] (459 nmi, 528 mi)
  • Combat radius: 300 km[98] (162 nmi, 186 mi)
  • Ferry range: 3,000 km[64](1,840 mi)
  • Service ceiling: 15,250 m[97] (50,000 ft)
  • Wing loading: 247 kg/m² (50.7 lb/ft²)
  • Thrust/weight: 1.07[90]
  • g-limits: +8/−3.5 g[90]

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

HAL Tejas carrying R-73 missile and Drop Tank.

File:Tejas weapon display Aero India 2011.JPG

Tejas weapon display Aero India 2011

See also[]

References[]

Notes[]

  1. The term "tailless" here means that the aircraft lacks horizontal tailplanes; there is still a single vertical tailfin.
  2. According to then Scientific Advisor to Defence Minister, Dr. Vasudev K. Aatre, "Tejas" (Sanskrit, meaning "Radiance" or "Radiant Energy") was selected from a list of 20 names considered for the LCA; the other alternate name would have beenSarang.
  3. Note: The LRDE is sometimes mis-abbreviated as "ERDE". To distinguish between "electrical" and "electronic", the latter is abbreviated with the first letter of its Latin root (lektra). The same approach is used with for the DLRL.
  4. Ericsson Microwave Systems was bought by Saab in June 2006;Ferranti Defence Systems Integration was acquired by GEC-Marconi in 1990, which in turn merged with British Aerospace (BAe) to form BAE Systems in November 1999.
  5. The Westinghouse — now Northrop Grumman — AN/APG-66, which is carried on the F-16, was among the radars evaluated by the ADA in 1992.[21]
  6. Since India does not possess suitable aircraft, the high-altitude testing of the Kaveri is contracted to Russia, which uses a Tu-16 bomber for the purpose. Another Kaveri engine was delivered to Russia for further flight testing from June to September 2006, but on an Il-76 testbed instead of a Tu-16.

Citations[]

  1. 1.0 1.1 1.2 "Tejas LSP-8 makes its maiden flight." The New Indian Express, 1 April 2013. Retrieved: 1 April 2013.
  2. Govindasamy, Siva."India rules out foreign help for Tejas LCA." Flight International, 7 March 2008. Retrieved: 29 May 2012.
  3. Majumdar, Bappa."India's light combat aircraft to phase out Russian jets." Reuters, 28 April 2009. Retrieved: 29 May 2012.
  4. 4.0 4.1 Shukla, Ajai. "Navy places INR 900-cr order for 6 Tejas LCA." news.rediff.com, 21 September 2009. Retrieved: 29 May 2012.
  5. "PM to select Sanskrit name for LCA on May 4."indiainfo.com, 27 April 2003. Retrieved: 29 May 2012.
  6. "LCA first prototype vehicle to fly next month." Indiainfo.com, 21 August 2003. Retrieved: 29 May 2012.
  7. 7.0 7.1 Jackson, et al. 2005, p. 195.
  8. "Induction of LCA Tejas postponed to November."
  9. Chatterjee, K. "Hindustan Fighter HF-24 Marut; Part I: Building India's Jet Fighter." bharat-rakshak.com. Retrieved: 23 August 2006.
  10. "Tejas Light Combat Aircraft (LCA)." Global Security, 2012. Retrieved: 29 May 2012.
  11. Iyer, Sukumar R. "LCA: Impact on Indian Defense." Bharat Rakshak Monitor, March–April 2001. Retrieved: 30 May 2012.
  12. "Remembrance of Aeronautical Matters Past." Vayu Aerospace & Defence Review, 2004. Retrieved: 7 March 2009.
  13. 13.0 13.1 "Light Combat Aircraft (LCA) Test-Flown Successfully." DRDO, January 2001. Retrieved: 29 May 2012.
  14. 14.0 14.1 14.2 Reddy, C. Manmohan."LCA economics." The Hindu, 16 September 2002. Retrieved: 29 May 2012.
  15. "Indigenous production of LCA soon." The Hindu, (Chennai, India), 4 August 2008. Retrieved: 29 May 2012.
  16. 16.0 16.1 "Tejas LCA exports likely after operational induction." Domain-b.com Retrieved: 16 January 2013.
  17. " Aircraft Museum: Tejas / Light Combat Aircraft (LCA)." Aerospaceweb. Retrieved: 29 May 2012.
  18. 18.0 18.1 18.2 "Tejas / Light Combat Aircraft (LCA) Light Multi-Role Fighter|." Aerospaceweb. Retrieved: 26 July 2013.
  19. "Interview with Mr. Shyam Shetty, head of the National Control Law team: NAL and LCA-1: Flight Control Laws." National Aerospace Laboratories (NAL) Information Pasteboard, 25 June – 1 July 2001.
  20. Taylor et al. 2005 p. 104.
  21. Sharma, Ravi."The LCA puzzle." Frontline, 16–29 July 2005. Retrieved: 30 May 2012.
  22. 22.0 22.1 Aroor, Shiv."Indigenous' aircraft needs foreign lift, for its radar."The Sunday Express, 8 April 2006. Retrieved: 30 May 2012.
  23. Mudur, Nirad. "Glitches in LCA radar." Vijay Times, 1 May 2006. Retrieved: 30 May 2012.
  24. "AESA Programme For Tejas Scans For Development Partner." Indian-military.org. Retrieved: 30 May 2012.
  25. Sharma, Ravi. "LCA to be fitted with Israeli multi-mode radar." The Hindu, (Chennai, India), 3 October 2008. Retrieved: 30 May 2012.
  26. "GE Receives $100+M Order for Tejas Fighter Engines." Defense Industry Daily. Retrieved: 30 May 2012.
  27. Shukla, Ajai. "Air Force says DRDO stalling Tejas fighter engine." Bharat-Rakshak.com, 28 June 2010. Retrieved: 30 May 2012.
  28. Sharma, Ravi."Kaveri engine programme delinked from the Tejas." The Hindu, (Chennai, India), 27 September 2008. Retrieved: 29 May 2012.
  29. Raghuvanshi, Vivek."Eurojet Bolsters Engine Offer for India's LCA."Defense News, 4 January 2010. Retrieved: 29 May 2012.
  30. "Defence Ministry plans to revive Tejas." Hindustan Times. Retrieved: 30 May 2012.
  31. Shukla, Ajai."American engine to power LCA." Bharat-Rakshak.com, 1 October 2010. Retrieved: 30 May 2012.
  32. "India picks GE's F414 for Tejas MkII fighter." Flight International, 1 October 2010. Retrieved: 30 May 2012.
  33. 33.0 33.1 Sharma, Ravi."IAF insists on changes to Tejas." The Hindu, 5 December 2008. Retrieved: 30 May 2012.
  34. 34.0 34.1 "Tejas soon to be inducted into IAF." The Economic Times, 8 January 2011. Retrieved: 30 May 2012.
  35. 35.0 35.1 "Light combat aircraft flies with near-full gear." Daily News and Analysis, 23 April 2010. Retrieved: 30 May 2012.
  36. "IAF team to oversee LCA induction and operation." The Hindu, 12 December 2006. Retrieved: 30 May 2012.
  37. "Fighter project on fast track mode." newindpress.com, 6 April 2008. Retrieved: 30 May 2012.
  38. "India’s very own ‘Tejas’ takes to the skies; first squadron by 2013." Zeenews, 11 January 2011. Retrieved: 30 May 2012.
  39. "Fighter aircraft Tejas clocks fastest speed during testing."The Indian Express, 8 December 2009. Retrieved: 22 August 2011.
  40. 40.0 40.1 40.2 "LCA Set To Fly With Israeli Radar."Aviation Week, 22 April 2010. Retrieved: 30 May 2012.
  41. 41.0 41.1 "First flight of Tejas aircraft LSP-4." The Times of India, 2 June 2010. Retrieved: 30 May 2012.
  42. "Light combat aircraft Tejas undergoes second phase of hot weather trails." Daily News and Analysis. Retrieved: 30 May 2012.
  43. "Indian LCA Undergoing Sea Trials."Aviation Week, 15 September 2010. Retrieved: 30 May 2012.
  44. "Tejas debut flight operational configuration." Deccan Herald, 19 November 2010. Retrieved: 15 February 2011.
  45. "Tejas Trainer makes successful maiden flight." ada.gov.in. Retrieved: 30 May 2012.
  46. 46.0 46.1 Krishnan M., Anantha."Indian Navy fastens its seatbelt for Light Combat Aircraft Tejas." dnaindia.com, 23 June 2010. Retrieved: 30 May 2012.
  47. "Air force to get 20 more Tejas fighter aircraft, says Antony – Home." livemint.com. Retrieved: 30 May 2012.
  48. "LCA Tejas Mk-1." sawfnews.com. Retrieved: 30 May 2012.
  49. Krishnan M., Anantha."Tejas Gets Initial Operational Clearance." Aviation Week, 11 January 2011. Retrieved: 30 May 2012.
  50. Prasad, K. V. "Tejas gets Initial Operational Clearance." The Hindu, (Chennai, India), 10 January 2011. Retrieved: 30 May 2012.
  51. Anandan, S. "Key Tejas weapon trials begin in Jaisalmer." The Hindu (Kochi, India), 20 September 2011. Retrieved: 30 May 2012.
  52. "LCA Tejas: An Indian Fighter – With Foreign Help." Defense Industry Daily, 30 April 2012. Retrieved: 30 May 2012.
  53. Pandit, Rajat. "Tejas won't become fully operational before 2013." The Times of India, 5 October 2011. Retrieved: 30 May 2012.
  54. Rajat, Pandit."UPA's major goof up: Tejas inducted." The Economic Times, 24 May 2012. Retrieved: 30 May 2012.
  55. "Failure of Indian LCA Tejas." Daily Mail, 2010. Retrieved: 30 May 2012.
  56. 56.0 56.1 56.2 56.3 56.4 Kumar, Chethan. "LCA naval variant’s first flight on Friday." Deccan Herald, 25 April 2012. Retrieved: 30 May 2012.
  57. "Defence News: LCA Completes Successful Bombing Runs." Defencenews.in.Retrieved: 17 September 2012.
  58. "Flight Test News." Aeronautical Development Agency (Bangalore, India), 16 April 2012. Retrieved: 30 May 2012.
  59. "Rs 25k cr Tejas won’t be ready before 2015." The Times of India, 22 July 2012.
  60. Shukla, Ajai. "After three months on ground, combat aircraft Tejas resumes test flight." Business Standard, 27 November 2012. Retrieved: 29 November 2012.
  61. http://www.ada.gov.in/archives.htm
  62. "Press Releases." Press Information Bureau, Government of India. Retrieved: 5 August 2013.
  63. "LCA and its Features." ada.gov. Retrieved: 24 September 2006.
  64. 64.0 64.1 64.2 64.3 " Tejas Light Combat Supersonic Fighter, India". Air force Technology. Retrieved: 26 July 2013.
  65. 65.0 65.1 "Tejas given Initial Operational Clearance." Facenfacts.com, 10 January 2011. Retrieved: 26 July 2013.
  66. Harry, B. "Radiance of the Tejas (2 Parts)." Vayu Aerospace & Defence Review, Vol. I, February 2005; Vol. II, April 2005.
  67. Prakash, Sqn. Ldr. B.G. "Dreams lighten in LCA." Strategic Affairs: Technology, 16 February 2001, p. 3.
  68. "Aircraft: LCA." Space Transport, 19 August 2002. Retrieved: 30 May 2012.
  69. "India: LCA Tejas by 2010 – But Foreign Help Sought With Engine." Defense Industry Daily, 17 February 2006. Retrieved 30 May 2012.
  70. Wollen, M. S. D., Air Marshal (Retd.) "The Light Combat Aircraft Story." Bharat Rakshak Monitor, March–April 2001. Retrieved: 30 May 2012.
  71. "KH T 2009."Aeronautical Development Agency. Retrieved: 24 September 2006.
  72. Iype, George.rediff.com "Will the LCA fly?" Rediff.com, 5 December 2000. Retrieved: 30 May 2012.
  73. "EL/M-2032." Deagel.com. Retrieved: 29 May 2012.
  74. Pubby, Manu."Israel, EU in contention to co-develop radars for Tejas." The Indian Express, 14 July 2010. Retrieved: 29 May 2012.
  75. Raghuvanshi, Vivek."India, Israel Propose Joint Electronic Warfare Venture." Rantburg, 24 July 2006. Retrieved: 30 May 2012.
  76. Harry, B. "Report from DEFEXPO-2004." ACIG.org. Retrieved: 30 May 2012.
  77. "IAF begins establishing first LCA squadron." Deccan Herald. Retrieved: 30 May 2012.
  78. "PIBNaval Version of Light Combat Aircraft Rolls out a Defining and Memorable Occasion for the Nation -Antony." pib.nic.in. Retrieved: 30 May 2012.
  79. 79.0 79.1 "India flies another Tejas." aviationweek.com. Retrieved: 15 February 2011.
  80. Shukla, Ajai. "Tejas boosts test programme." Business Standard. Retrieved: 22 November 2011.
  81. "India To Fly Tejas LSP-5 Soon." aviationweek.com. Retrieved: 15 February 2011.
  82. "HAL Tejas Multirole Aircraft – History, Specs and Pictures – Military Aircraft." militaryfactory.com. Retrieved: 15 February 2011.
  83. 83.0 83.1 "Tejas LSP-7 & 8 in air by end of this year: ADA." idrw.org. Retrieved: 15 June 2011.
  84. Unnithan, Sandeep."First indigenous aircraft carrier to be launched next year: Navy chief." indiatoday, 2 December 2009.
  85. "India test flies naval variant of Light Combat Aircraft: IANS." ibnlive.in.com, 28 April 2012. Retrieved: 29 May 2012.
  86. Shetty, Vinayak. "Tejas Mk-2 will incorporate 5 gen fighter elements." Security Magazine, October 2010. Retrieved: 30 May 2012.
  87. "Engines History." lca-tejas.org. Retrieved: 29 May 2012.
  88. "Tejas handed over to IAF."frontierindia.net. Retrieved: 30 May 2012.
  89. "IAF inducts indigenous LCA Tejas." indiavoice.info. Retrieved: 30 May 2012.
  90. 90.0 90.1 90.2 "Leading particulars and performance." tejas.gov.in. Retrieved: 10 December 2012.
  91. "DRDO TechFocus." DRDO, February 2011. Retrieved 10 December 2012.
  92. "HAL Tejas spec board image." blogspot.com. Retrieved: 30 May 2012.
  93. "Tejas, India".naval-technology.com. Retrieved: 24 July 2012.
  94. "Specifications, Powerplant". tejas.gov.in. Retrieved 16 September 2012.
  95. "India seeks proposals for Tejas 2 fighter engine". Flight International, 30 July 2009.
  96. "F404-GE-IN20." Deagel.com. Retrieved: 17 September 2012.
  97. 97.0 97.1 "Light Combat Aircraft (LCA) (Tejas)." lca-tejas.org. Retrieved: 20 November 2012.
  98. 98.0 98.1 "HAL Tejas". Jane's Information Group, 11 September 2012.
  99. 99.0 99.1 Harry, B. "Aero India 2003 – Part 1." Acig.org. Retrieved: 30 May 2012.
  100. "Israeli Rafael To Deliver Litening Targeting Pods For HAL Tejas LCA Fighter Jet Programme." India Defence. Retrieved: 30 May 2012.
  101. "Litening pod tested on LCA Tejas." Frontier India– News, Analysis, Opinion. Retrieved: 30 May 2012.
  102. "Derby Missiles Selected to Arm India's Tejas Fighters." defense-update.com. Retrieved: 15 February 2011.

Bibliography[]

  • Jackson, Paul, Kenneth Munson and Lindsay Peacock, eds. "ADA Tejas." Jane’s All The World’s Aircraft 2005–06. Coulsdon, Surrey, UK: Jane's Information Group Limited, 2005. ISBN 0-7106-2684-3.
  • Taylor, John W. R., Kenneth Munson and Michael J. H. Taylor, eds. "HAL Light Combat Aircraft." Jane's All The World's Aircraft 1989–1990. Coulsdon, Surrey, UK: Jane's Information Group Limited, 2005. ISBN 0-7106-0896-9.

External links[]

Features and analysis:

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