Light Combat Aircraft

R.L.N.Sarma and Sunil Sainis

The Light Combat Aircraft (LCA) is India’s second attempt at designing and developing an indigenous fighter aircraft after the HF-24 Marut of the 1950s. Before going into the details of the LCA project, a brief insight into India’s first home-built aircraft project HF-24 is relevant. The Marut was conceived in the mid-1950s, after the Air Staff expressed the need for an indigenously built multi-role fighter. During the 1950s, Indian infrastructure in terms of design and manufacture of aircraft was quite rudimentary. The Indian aviation industry’s only aircraft design experience was limited to that of a turboprop trainer, HT-2. Manufacturing capabilities were limited to licensed-production of imported vintage aircraft. Considering these factors, it was an audacious decision to embark upon such a complex project. Though Marut finally entered service with the IAF, the search for a suitable power plant dragged on without any significant success and ultimately led to the demise of the project in the early 1970s. Acquisition of foreign aircraft also led to the withering away of any technical expertise gained during the Marut exercise. As a result, the LCA project was started virtually from scratch. The LCA project - like the Marut - was characterized by audacious thinking in terms of creating a world class fighter with state-of-the-art features.

LCA Chronicle

The Government of India first announced its intentions to start the LCA program in 1980. A feasibility study was conducted in 1983. And in 1984, the Aeronautical Development Agency (ADA) was established as the nodal agency to carry out the design and development of LCA. In 1986, a contract was signed with General Electric (GE) for the supply of 11 General Electric F-404 engines. These engines were meant to power the initial Technology Demonstrators (TD) and Prototype Vehicles (PV), pending their eventual replacement by the indigenous Kaveri, design work for which was sanctioned in 1988. The actual design and development work of LCA commenced in 1992 and the first aircraft TD-1 was rolled out at Bangalore three years later. Flight control software integration tests for TD-1 began in 1996, with help from Lockheed-Martin of US. However, this cooperation came to an abrupt halt in 1998 after the nuclear tests at Pokhran. This set back the first test flight by a couple of years. System integration efforts and taxi trials were prolonged till the end of 2000. Finally, on January 4 2001, the TD-1 (powered by the F-404 engine) made its maiden flight. The aircraft was flown by Wing Cdr Rajiv Kothiyal of the National Flight Test Center. 

The test flight lasted approximately twenty minutes. The aircraft was put through the following flight routines. After take-off, the aircraft climbed to an altitude of 3,000m (as a safety measure to recover from any flight contingency). During the flight the aircraft flew with its landing gear extended and carried out trials at low speed and stress. Maximum speed flown was under 450 km/hr and maneuvers of 2 G were executed in turns. The aircraft was also put into a stall from which it successfully recovered. Flaps were tested at an altitude of 3,000 m. The test flight was used to validate the aircraft’s flight characteristics and the structural integrity of composite materials used for its construction. The following technologies were also tested as part of flight: main communication system for air-to-air and air-to-ground communication, Standby communication system, radio altimeter for measuring the aircraft's altitude while in flight, audio management unit for giving different audio signals to the pilot, identification friend or foe (IFF) systems, electrical and engine monitoring system, digital hydraulic electronic unit, Starter engine control unit, Digital Flight Control System, Pilot Vehicle Interface (PVI), Heads Up Display(HUD) and Multi Function Display(MFD) units.

The Kaveri engine has reportedly completed 1000 hours of tests aboard a modified Russian Tu-16 aircraft. Further testing of 1000 hours is required before it is ready to be mated with PV-1. Performance tests at high inlet pressure and temperature corresponding to flight at Mach nos. up to 0.9 and altitude up to 11 km have been carried out. These tests indicated structural integrity and established flat rating concepts. Tests were also conducted successfully for generation of compressor characteristics, surge margins and performance at supercritical air entry conditions. Engine light-up trials at various altitudes and Flight Mach nos. were tried and found satisfactory. Air turbine starter tests at various altitudes were tried successfully. Combustion flame stability tests were conducted for altitudes of 12, 13.5 and l5 km at M=0.3,0.35 and O.4, respectively and were found to be satisfactory. It is expected that the first Kaveri will be mated with PV-1 before 2002. The two-seat LCA conversion trainer is expected to be ready by 2003.

Future developmental plans for the LCA are as follows. TD-2, which is currently undergoing system integration tests, is expected to fly in 3-4 months from now. Work on PV-1, 2 and 3 is underway and PV-1 is expected to make its maiden flight towards the end of 2001. The significance of PV-1 is that it will be a fully weapons-integrated version of LCA. Further, future spin-offs from the LCA project include a two-seater fighter and an Intermediate Jet Trainer (IJT). Estimates for its entry-into-service dates range from 2007-2015. However, top scientists involved with the project and independent aviation experts have strongly denied reports that LCA would be obsolete by the time of induction and have asserted that the LCA systems can remain contemporary for the next 45 years. 

Principal Players

The development effort for the LCA is spearheaded by Aeronautical Development Agency (ADA). The principal partner of ADA is Hindustan Aeronautics Limited (HAL). A number of Public Sector Units (PSUs), DRDO and CSIR labs, ordnance factories, IAF establishments, educational institutions like IITs and IISc and a large number (about 300) of private industries have contributed their mite to the project. Thus, the LCA programme is truly a national effort encompassing a wide spectrum of organisations, both public and private.

LCA Features

The LCA is billed to be the world’s smallest, lightweight, supersonic, multi-role, single-seat fighter designed to function as IAF’s frontline, multi-mission tactical aircraft. Although the term light can be misleading because the LCA will be able to deliver as much ordinance as the much larger MiG-27s. It is primarily intended to replace the aging fleet of IAF Mig-21s. Some of its characteristic design and functional features are as follows. It has a delta wing configuration with a single tail fin and no tailplanes or foreplanes. The airframe is made of aluminium-lithium alloys (30%), carbon-carbon composites (40%) and titanium (3%), that contribute to its lightweight. LCA incorporates modern design concepts and the state-of-art technologies such as relaxed static stability, fly-by-wire Flight Control System, Advanced Digital Cockpit, Multi-Mode Radar, Integrated Digital Avionics System, Advanced Composite Material Structures and a Flat Rated Engine. LCA’s pure delta-wing design implies that it is an inherently unstable platform, which - however - gives it improved aerodynamic efficiency, enhanced agility and maneuverability. Advanced on-board quadruplex computers ensure the stability of the aircraft while flying (called fly-by-wire). Other functional features of the LCA include short take off and landing, excellent maintainability and a wide range of weapon fits. The on-board avionics enhance the role of LCA as an effective weapons platform. The Integrated Digital Avionics Suite of LCA is characterized by its interface with all other aircraft systems such USMS, Propulsion System, Electrical System and Flight control System. The glass cockpit and hands on throttle and stick (HOTAS) controls reduce pilot workload. Accurate navigation and weapon aiming information on the HUD helps the pilot achieve his/her mission effectively. A ring laser gyro (RLG) based inertial navigation system (INS) provides accurate navigation guidance to the pilot. LCA has considerable weapons-carrying capability. There are a total of 7 hard points (3 below each wing and one below the fuselage) to carry a variety of missiles, bombs and rockets as per mission requirements. The advanced cockpit and the digital avionics give LCA a very good point and shoot capability with a quick turn around time. LCA has provisions for fuel drop-tanks and in-flight refueling that extend its range and endurance. Further, supersonic speeds at all altitudes and the availability of high performance radar give the LCA effective Beyond Visual Range (BVR) attack capabilities. 

 Notes

1. ‘Indigenous LCA makes its maiden flight’. Rediff. 4 January 2001. http://www.rediff.com/news/2001/jan/04lca1.htm
2. ‘Giant leap for Indian aviation’. Economic Times. 5 January 2001. http://www.economictimes.com/today/05econ04.htm
3. ‘LCA test flight successful’. The Hindu. 5 January 2001. http://www.indiaserver.com/thehindu/2001/01/05/stories/01050002.htm
4. Defence India http://www.defenceindia.com/test1/templ.php3?filename=chronology.html
5. ‘Will the LCA fly?’. Rediff. 5 December 2000. http://www.rediff.com/news/2000/dec/05spec.htm
6. ‘Making of the LCA’. India Today. 5 January 2001 http://www.india-today.com/itoday/20010115/defence2.shtml - fact
7. ‘LCA to undergo more ground runs’. Businessline. 27 December 2001. http://www.indiaserver.com/businessline/2000/12/27/stories/142704yb.htm
8. ‘Light combat craft takes India into club class’. Times of India. 5 January 2001. http://www.timesofindia.com/today/05home1.htm
9. ‘First operational LCA to be ready by 2007’. The Hindu. 5 January 2001. http://www.indiaserver.com/thehindu/2001/01/05/stories/0205000f.htm
10. ‘LCA far from acquiring combat worthiness’ The Hindu. 5 January 2001. http://www.indiaserver.com/thehindu/2001/01/05/stories/0205000e.htm
11. Light Combat Aircraft (LCA) http://iae.net/users/wbergmns/info/lca.htm
12. THE HF-24 Marut (part I) http://www.bharat-rakshak.com/IAF/Features/Marut1.html

All photos courtesy of NFTC and ADA