Light Combat Aircraft:Technical Specifications, Indian Airforce
Light Combat Aircraft:Technical Specifications


Type: Light Combat Aircraft(LCA)
Country: India
Function: fighter
Crew: 1
Engines: 1(83.4 kN GTRE GTX-35VS augmented turbofan)
Wing Span: 8.20 m
Length: 13.20 m
Empty Weight: 5500 kg
Ceiling: 16400 m
Armament: GSh-23 twin-barrel 23mm cannon(220 rounds);
7 hardpoints, max external load over 4000 kg

The Indian Light Combat Aircraft(LCA) is the world's smallest, light weight, multi-role combat aircraft designed to meet the requirements of Indian Air Force as its frontline multi-mission single-seat tactical aircraft to replace the MiG-21 series of aircraft. It is configured to carry indigenous ASTRA medium range air-to-air missile, close combat missiles and an integral 23 mm cannon. It has also been equipped with electronic counter-counter measure(ECCM) devices developed by the Advanced System Integration and Evaluation Organisation.

The delta wing configuration , with no tailplanes or foreplanes, features a single vertical fin. The LCA is constructed of aluminium-lithium alloys, carbon-fibre composites, and titanium. LCA integrates 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.

The LCA design has been configured to match the demands of modern combat scenario such as speed, acceleration, maneuverability and agility. Short takeoff and landing, excellent flight performance, safety, reliability and maintainability, are salient features of LCA design. The LCA integrates modern design concepts like static instability, digital fly-by-wire flight control system, integrated avionics, glass cockpit, primary composite structure, multi-mode radar, microprocessor based utility and brake management systems.

The avionics system enhances the role of Light Combat Aircraft as an effective weapon platform. The glass cockpit and hands on throttle and stick(HOTAS) controls reduce pilot workload. Accurate navigation and weapon aiming information on the head up display helps the pilot achieve his mission effectively. The multifunction displays provide information on engine, hydraulics, electrical, flight control and environmental control system on a need-to-know basis along with basic flight and tactical information. Dual redundant display processors(DP) generate 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.

A state-of-the-art multi-mode radar(MMR), laser designator pod(LDP), forward looking infra-red(FLIR) and other opto-electronic sensors provide accurate target information to enhance kill probabilities. A ring laser gyro(RLG)-based inertial navigation system(INS), provides accurate navigation guidance to the pilot. An advanced electronic warfare(EW) suite enhances the aircraft survivability during deep penetration and combat. Secure and jam-resistant communication systems, such as IFF, VHF/UHF and air-to-air/air-to-ground data link are provided as a part of the avionics suite. All these systems are integrated on three 1553B buses by a centralised 32-bit mission computer(MC) with high throughput which performs weapon computations and flight management, and reconfiguration/redundancy management. Reversionary mission functions are provided by a control and coding unit(CCU). Most of these subsystems have been developed indigenously.

The digital FBW system of the LCA is built around a quadruplex redundant architecture to give it a fail op-fail op-fail safe capability. It employs a powerful digital flight control computer(DFCC) comprising four computing channels, each powered by an independent power supply and all housed in a single line replaceable unit(LRU). The system is designed to meet a probability of loss of control of better than 1x10-7 per flight hour. The DFCC channels are built around 32-bit microprocessors and use a safe subset of Ada language for the implementation of software. The DFCC receives signals from quad rate, acceleration sensors, pilot control stick, rudder pedal, triplex air data system, dual air flow angle sensors, etc. The DFCC channels excite and control the elevon, rudder and leading edge slat hydraulic actuators.

The computer interfaces with pilot display elements like multifunction displays through MIL-STD-1553B avionics bus and RS 422 serial link. The digital FBW system of the LCA is built around a quadruplex redundant architecture to give it a fail op-fail op-fail safe capability. It employs a powerful digital flight control computer(DFCC) comprising four computing channels, each powered by an independent power supply and all housed in a single line replaceable unit(LRU). The system is designed to meet a probability of loss of control of better than 1x107 per flight hour. The DFCC channels are built around 32-bit microprocessors and use a safe subset of Ada language for the implementation of software. The DFCC receives signals from quad rate, acceleration sensors, pilot control stick, rudder pedal, triplex air data system, dual air flow angle sensors, etc. The DFCC channels excite and control the elevon, rudder and leading edge slat hydraulic actuators. The computer interfaces with pilot display elements like multifunction displays through MIL-STD-1553B avionics bus and RS 422 serial link.

Multi-mode radar(MMR), the primary mission sensor of the LCA in its air defence role, will be a key determinant of the operational effectiveness of the fighter. This is an X-band, pulse Doppler radar with air-to-air, air-to-ground and air-to-sea modes. Its track-while-scan capability caters to radar functions under multiple target environment. The antenna is a light weight(<5 kg), low profile slotted waveguide array with a multilayer feed network for broad band operation. The salient technical features are: two plane monopulse signals, low side lobe levels and integrated IFF, and GUARD and BITE channels. The heart of MMR is the signal processor, which is built around VLSI-ASICs and i960 processors to meet the functional needs of MMR in different modes of its operation. Its role is to process the radar receiver output, detect and locate targets, create ground map, and provide contour map when selected. Post-detection processor resolves range and Doppler ambiguities and forms plots for subsequent data processor. The special feature of signal processor is its real-time configurability to adapt to requirements depending on selected mode of operation.

Seven weapon stations provided on LCA offer flexibility in the choice of weapons LCA can carry in various mission roles. Provision of drop tanks and inflight refueling probe ensure extended range and flight endurance of demanding missions. Provisions for the growth of hardware and software in the avionics and flight control system, available in LCA, ensure to maintain its effectiveness and advantages as a frontline fighter throughout its service life. For maintenance the aircraft has more than five hundred Line Replaceable Units(LRSs), each tested for performance and capability to meet the severe operational conditions to be encountered.

Hindustan Aeronautics Limited(HAL) is the Principal Partner in the design and fabrication of LCA and its integration leading to flight testing. The LCA has been designed and developed by a consortium of five aircraft research, design, production and product support organizations pooled by the Bangalore-based Aeronautical Development Agency(ADA), under Department of Defense Research and Development Organization(DRDO). Various international aircraft and system manufacturers are also participating in the program with supply of specific equipment, design consultancy and support. For example, GE Aircraft Engines provides the propulsion. Two aircraft technology demonstrators are powered by single GE F404/F2J3 augmented turbofan engines. Regular flights with the state-of-the-art "Kaveri" engine, being developed by the Gas Turbine Research Establishment(GTRE) in Bangalore, are planned by 2002, although by mid-1999 the Kaveri engine had yet to achieve the required thrust-to-weight ratio.

Indigenous HUD

India replicated classified technology used by advanced nations using a state-of-the-art head-up display system for its Light Combat Aircraft. This helps a pilot view both vital information and outside world without changing his line of sight. The Indian HUD, claimed to be superior to similar systems in the international market, can also be used in aiming missiles and guns during combat.

The indigenous HUD, developed at the Central Scientific Instruments Organisation in Chandigarh, has been handed over to the Aeronautics Development Establishment, Bangalore. The technology is now being modified for the Sukhoi, Jaguar and MIG-27 aircraft, CSIO director R P Bajpai said. Senior army officers have watched demonstrations of the technology.

CSIO scientists said they had initiated the HUD project in 1992 and developed their unit "from scratch, with no reverse engineering involved". In laymen's terms this means they made it all themselves. Vital information about the aircraft, and information about altitude, pressure etc, are superimposed on the pilot's viewing window. This means the pilot does not have switch from watching a bank of instruments to the outside world. The time taken to adjust is often crucial in extreme situations.

So the pilot can fly the aircraft "head up", reducing his workload and enhancing his fighting capacity. "HUD is a contemporary, state-of-the-art technology in international market," says V M L Narasimham, head of CSIO's Applied Optics division, whose scientists developed the vital technology. For example, compared to Israel's HUD, the CSIO equipment is noiseless, silent, and offers a better field of view, he says, adding that it is compact, reliable, non-reflective and designed for high-performance aircraft. The HUD will be displayed at the coming air show in Bangalore later this year.

The team has delivered three HUDs to ADE. One unit has been tested for environmental stress specifications and is ready for integration with the LCA. The second is being readied for flight safety tests under simulated conditions, while the third has undergone form fit and function testing. A fourth HUD unit, currently undergoing tests at CSIO, will be handed over to ADE within 10 days. In two to three months, two airworthy units would be ready, Narasimhan said.

The Bharat Electronics Limited at Panchkula near Chandigarh has placed an order for five HUDs which will cost Rs six million a piece. BEL will begin HUD production later. CSIO scientists will next work on a helmet-mounted display, specifications for which are being worked out by the ADA. The institute is also working fire safety sensors for LCA.

ARDE develops safe ejector system for LCA

In a significant achievement, the Pune-based premier Armament Research and Development Establishment has developed an innovative high-tech line-charged Canopy Severance System for the Light Combat Aircraft, for safe ejection of the pilot. Earlier, the ARDE had successfully produced the 'Pinaka' Multi Barrel Rocket Launcher System for the Indian armed forces, to give it concentrated high volume firepower to destroy enemy targets as demanded by the top brass of the Indian army.

After nearly 40 test trials, Martin Baker AIC Co, London, arguably the top organisation in the world to certify the safety pilot ejection system, has certified commercial production of canopy severance system. The sophisticated system is technologically so advanced that it requires mere milliseconds to eject the pilot to safety in case of a crash.

"While in the conventional system, the entire canopy flies off and can result in an injury to the pilot, in the newly indigenously developed system, only a certain portion of the canopy which is line-charged, gets severed. This absolutely minimises injury to the pilot," scientist Dr Sudharshan Kumar Salwan, director, ARDE, said He stressed that no aircraft in the world had this kind of live system which could be operated from outside the aircraft, especially when the pilot was unconscious due to some injuries or in the event of crash-landing.

According to scientist Dr K S Rajgopal, head of the weapons system, ARDE, the Canopy Severance System could be operated by an external initiator. "The initiator generates a detonation wave which is transmitted in a totally contained manner to a line charger pasted along the canopy and thus cutting it peripherally. This helps in rescuing the pilot," he explained. Salwan said after the new system was tested at Martin Bakers, UK, recently, it had been approved for use in the LCA.

Two LCAs fitted with the system were already in operation for the Indian Army, he disclosed, adding that army authorities were satisfied with its functional operation. Pointing out that the minimum time in the range of milliseconds should be used in saving the pilot in distress, he pointed out that while the conventional ejection system was 95 per cent successful, the new system would take it to 99.9 per cent.

Salwan said the system was fitted with sophisticated sensors to achieve the expected results as successfully demonstrated in the UK. He said the army chief, General Ved Prakash Malik, during his recent visit to the ARDE was fully satisfied with the new system. With the green signal obtained from the Defence Research and Development Organisation, which sets the target and supervises the working of ARDE and 40 other armament group of labs servicing the Army, Navy and Air Force, commercial production of the new canopy system for the use of the Indian armed forces will commence shortly, Salwan said.

Asked if it will also be sold in the international market, he said after meeting the requirements of the Indian armed forces, its business potential in the world market will be considered. In another achievement, the ARDE has also successfully developed an 'air launch rescue' system, christened "Rakshak"(Saviour) for rescuing marooned sailors. After successful field trials at sea, this system has been approved and accepted by the Indian Navy. "Rescue of marooned sailors is always an emergency operation. Though a search aircraft may be able to locate the sailors, it has to call a ship or helicopter to rescue them. But often it is too late for the help to arrive," Salwan said.

The rescue system is a simple dinghy, inflated with carbon dioxide that can be dropped from an aircraft. An impact sophisticated sensor is fitted in its nose and has a parachute at its other end. On release from the aircraft, the parachute opens after three to four seconds and the dinghy descends. The impact sensor senses impact on water and opens out the shell and also operates a valve to inflate the dinghy. The dinghy with emergency rations, water and pyrosignals is ready in just about 60 seconds, Salwan pointed out.

Established in 1958, the ARDE, largest lab among the 40 armament group of labs in the country under the DRDO, employs over 1,700 scientists, engineers, officers in uniform, technical, industrial staff and support services. The ARDE is involved in research, development, prototyping, test and evaluation and transfer of technology activities, including limited scale of pilot plant production of crucial items in the complex, multi-disciplinary field of conventional armament technology for the army, navy and air force.