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Saras Light Transport Aircraft (LTA)

Named Saras, after the Indian crane known for its grace and beauty in flight, the Light Transport Aircraft (LTA) has the design objective of being able to carry between eight and 14 passengers and extendable to an 18-passenger variant, in multiple modes of operation.

The flight-testing expertise and resources in India have matured adequately to undertake prototype flight-testing. The Light Transport Aircraft (LTA) program, SARAS a turboprop aircraft being developed indigenously by National Aerospace Laboratories (NAL) of Government of India, is the first civil aircraft program aimed at certification standard, FAR 25. The program is unique in that the propeller configuration of SARAS is pusher type and it is the first indigenously designed civil transport aircraft in India. In light of its unique configuration and in absence of any precedence for certification of an indigenously designed and developed aircraft against a FAR airworthiness standard in India, the prototype flight-testing of SARAS aircraft becomes critical.

The SARAS programme is a NAL initiative to create a vibrant Indian civil aviation industry. The programme was the outcome of a series of studies in the late 1980's which pointed to the requirement of a fourth level ("feeder) airline for India.

SARAS is a twin turbo-prop multi-role aircraft with air taxi and commuter services as its primary roles. SARAS will have a seating capacity of up to 14 passengers in the high density version. With a large and pressurised cabin, the aircraft will have a level of comfort comparable to regional aircraft. SARAS will be well-suited to fulfil a variety of other roles such as executive transport, light package carrier, remote sensing and aerial research service, coast guard, border patrol, air ambulance and other community services.

SARAS is powered by two Pratt and Whitney Canada PT6A-66 engines driving 2.16m diameter 5 bladed propellers at 2000 rpm in a pusher configuration. The engines are mounted on stub wings locate at aft fuselage resulting in quieter cabin and undisturbed flow on the wing.

Attention has been given right from the beginning for easy maintenance and thus to increase aircraft availability. Equipment needing inspection / maintenance are provided easy access. The PT6A-66 engine is of modular construction and thus easy to maintain. Furthermore, the cowling is designed in such a way that the front and rear ends are removable and centre section has swinging doors and panels to have full access to servicing points on engine and aircraft accessories. Hot section inspection which is usually carried at mid time between overhauls can be done in-situ by removing rear end of nacelle. The avionics equipment, hydraulic system and the air conditioning system bays, all have large doors for easy access.

In mid 1980s, Research Council recommended that NAL should study the civil aviation requirements of India and recommended ways and means of establishing a viable civil aviation industry. It further recommended that NAL should carryout a formal techno economical feasibility study of a multi role Light Transport Aircraft (LTA - renamed SARAS in October 1993). The feasibility study (November 1989) showed that there was a significant demand for a 9-14 seat multi-role LTA in the country and estimated a market potential of about 250-350 aircraft in the next 10 years. NAL submitted the feasibility study report to RC in November 1990 and started its search for an industrial partner. Though two organisations expressed their interest to be the industrial partners, none of these risk-sharing partnerships materialised, as these organisations backed out. In August 1995, RC recommended to put up the proposal to the competent financial authority (CFA) after identifying the industrial partner and the project cost was estimated at Rs.126 crore. The project was initially conceived in the 1990s as a joint project between India and Russia. However, India's National Aeronautics Ltd (NAL) decided to go solo with the 14-seater civil aircraft program when the Myasischev Design Bureau, the Russian state agency for civilian planes, backed out due to a financial crisis.

The first test flight of multirole light transport aircraft 'Saras' was scheduled for December 2002. The project of 'Saras' was sanctioned on September, 24 1999 with initial schedule of its maiden flight by March 2001. The delay was attributed to technology embargoes and technological complexities. As against the target of January 2001, the Prototype-I flew in May 2004, i.e. after a delay of more than three years. Prototype-II undertook its first flight in April 2007, after a delay of more than five years. Due to the above time overrun, the cost of the project increased by Rs.22.53 crore i.e. a cost escalation of almost 17 percent.

The flight-testing expertise and resources in India have matured adequately to undertake prototype flight-testing. The Light Transport Aircraft (LTA) program, SARAS a turboprop aircraft being developed indigenously by National Aerospace Laboratories (NAL) of Government of India, is the first civil aircraft program aimed at certification standard, FAR 25 [1]. The program is unique in that the propeller configuration of SARAS is pusher type and it is the first indigenously designed civil transport aircraft in India. In light of its unique configuration and in absence of any precedence for certification of an indigenously designed and developed aircraft against a FAR airworthiness standard in India, the prototype flight-testing of SARAS aircraft becomes critical. The first flight of SARAS aircraft was flown on 29 May 2004 and the prototype flight-testing was progressing satisfactorily.

Development of SARAS suffered from delays and deficient project management. Even after a lapse of eight years and cost overrun of Rs.22.53 crore, NAL is awaiting certification of airworthiness for SARAS aircraft from Director General of Civil Aviation (DGCA) as NAL failed to bring down its weight within the permissible limit and is yet to carry out various tests and generate documentation. As of 2008, flight certification was expected only after 2010 and NAL may have to make a third prototype as well.

The project was dumped by the previous government, after an accident during a test flight in 2009. It was revived more than five years later by the Narendra Modi government. The aircraft has since undergone several design modifications and improvements, like 2x1200 hp engines and 104-inch diameter propeller, assembles to cater to the second segment climb gradient requirements, improved flight control system, rudder area, and indigenously developed stall warning system, etc. India needs 120-160 aircraft of this genre both civilian and military versions in the next 10 years.

A modified prototype of the 14-seater transport aircraft started making low-speed taxi trials in early August 2017. Air Force pilots have completed five runs of around 45 minutes each and will next move on to high-speed taxi tests, according to Jitendra Jadhav, Director, National Aerospace Laboratories, under the Council for Scientific & Industrial Research (CSIR). Dr. Jadhav said, We plan to fly the aircraft in the first week of October after the high speed taxi trials are completed. We made more than 10 modifications since the accident. The performance of the planes systems after the modification will be evaluated during the flights.

  1. The control forces have been significantly reduced.
  2. The nacelle design (for engine mount) has been made optimal.
  3. Environmental control systems, cabin pressurization systems have been modified.
  4. Automatic avionics stall warning system included.
  5. Linear flap track and trim taps on elevator modified.
  6. Rudder area enhanced for better controllability.
  7. Flight test instrumentation modified.
  8. Electrical systems modified to reduce voltage losses.
  9. Air data system has been provided with the nose boom for redundancy.
  10. Complete borosopic inspection of the aircraft to eliminate any doubts about corrosion.
  11. Computer-based failure analysis of engine, elevator jamming and ailerons power adequacy.
  12. Simulator upgraded to the high-fidelity.

About 25 flights were planned in the first set of the modified prototype, the PT1N. By the end of 2019, NAL planned to fly a production-standard version for air-worthiness certification. Except for minimum maintenance engine runs, the 14-seater aircraft has not taxied or flown since one aircraft version crashed near Bengaluru in 2009 killing all three crew members. In February 2017, the Minister of Science & Technology in whose purview NAL and other CSIR labs fall said the government was intent on completing the planes development and making it flight worthy. The revival activities started with five ground-runs of its two Pratt & Whitney engines followed by the taxi trials. A few more LSTTs [low speed taxi trials] are due.

The 10-odd modifications were made to make it more pilot-friendly, agile, or easy to control; and to enable it to fly higher. The final Saras is planned to be able to cover 1,600 km at a maximum speed of 425 kmph, have a service ceiling of 9-10 km and fly continuously for five hours.

SARAS-MK2 will be the first indigenous light transport aircraft. According to NAL estimates, there is a demand for such aircraft with the requirement going up from 30-40 aircraft initially to 200 aircraft over the next 10-15 years. The aircraft was successfully test flown for the second time on 22 February 2018. This was the first of 20 test flights planned for the SARAS PT1N, before freezing the production version. India is looking to begin mass production of the indigenously developed multi-purpose light transport aircraft SARAS by the second half of this year. "The unit cost of the aircraft, with more than 70 percent indigenous content, will be around INR 40-45 crore ($6.25-7 million) as against INR 60-70 crore ($9.3-11 million) for imported ones and has far more benefits than what the imported aircraft offer," Harsh Vardhan, India's Minister for Science & Technology said 22 February 2018. India needs 120 to 160 civil and military versions of the aircraft in this genre in the next 10 years, Mr Vardhan said.

CSIR-NAL proposed to get the SARAS-Mk 2 version certified initially for military and subsequently for civil version. The NAL claims that the upgraded SARAS Mk2 version (19 seaters) will be at least 500 kilograms lighter than the current version which weighs around 7100 kilograms. It will have unique features, like high cruise speed, lower fuel consumption, short landing and take-off distances, low cabin noise, operable from high-altitude and hot airfields, with a pressurized cabin, operable from semi-prepared airfield and low acquisition and maintenance cost.

SARAS-MK1 SARAS-MK1 SARAS-MK1 SARAS-MK1 SARAS-MK1 SARAS-MK1

SARAS-MK2 SARAS-MK2 SARAS-MK2




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