Suranjan Das, one of IAF’s first Experimental Test Pilots who evaluated all jets for 20 years

Suranjan Das trod a road not travelled by any IAF pilot. His contribution to HF-24 Marut, India’s first homegrown fighter aircraft, was immense.

Suranjan Das getting into the cockpit of the Kiran prototype before the test flight.

As India’s defence aviation gets more atmanirbhar, we must reflect on the pioneer who paved the way for the special band of men who now test-fly the aircraft that are designed and manufactured in the country. Suranjan “Dasu” Das was not only one of the first two Experimental Test Pilots of the Indian Air Force but also the evaluator of every fighter/bomber/trainer acquired by it between 1950 and his untimely death in 1970.

Dasu was born on 22 February 1920 to Sudhi Ranjan Das, who himself was a public servant of distinction, being the fifth Chief Justice of India. Belonging to a family with an illustrious history in the making of India, Dasu graduated in Physics from St Xavier’s College in Calcutta. However, his yearnings for mechanical and aviation work was more. The family tried to dissuade him, and he was told that ‘if he could fly, a goat could too’. This silly metaphor proved prophetic — he join the IAF and went on to be, in the Experimental Test Pilots (ETP) community, considered the greatest of all time (GOAT).

Training in Canada and the UK

Sent to Canada for his initial flying training as part of the 19th course in 1943, Dasu was commissioned in the Indian Air Force (IAF) on his return in June 1945. He earned his operational spurs with the 8 Squadron and his technical bent of mind helped its engineers recover unserviceable vehicles or repair aircraft.

Dasu’s flying and mechanical skills led him to be selected for the 8th course at Empire Test Pilots School (ETPS) in the United Kingdom. Accompanying him on this trip in 1949, was Flight Lieutenant Roshan Lal Suri. On his return, Dasu was assigned the task of flight testing the licence-produced Vampire aircraft at Hindustan Aeronautics Limited (HAL). Deputed to HAL in 1951 and entrusted with the experimental flight testing of the HT-2 trainer, Dasu flew the machine to its limits to ensure that it was safe enough for trainees to fly and even had to bale out from the HT-2 when it did not recover from a spin during the trials, joining the caterpillar club. This experience added to India’s aviation learning curve as well, evident from Dasu’s remark: “Much knowledge was gained through development flying, but there had been a number of failures too, very common in this game, as each failure adds to the knowledge of both the ‘boffin’ and the ‘airframe driver’ which are there for keeps.” HT-2 would serve the IAF for over three decades and train thousands of pilots.

Armed with this experience in 1953, Dasu assumed command of the Aircraft Erection Unit at Bombay and got down to testing and certifying the ‘Toofani’ (Dassault Ouragan) aircraft as they were being assembled on arrival. He was one of the four pilots who ferried the first lot in from France. His experience also proved instrumental during the IAF’s hunt for its next fighter jet aircraft. Later that year, the IAF brass led by then Air Commodore Pratap Chandra Lal visited Europe to view various new fighter aircraft, a trip that subsequently led to the acquisitions of the Gnat, the Canberra, the Hunter, and the Mystere at the IAF. Dasu was the test flyer on all these evaluations.

Left to Right: Unidentified Indian Official, Sqn Ldr Suranjan Das, Sqn Ldr Roshan Suri, REAF Officer, Gp Capt H S Moolgavkar, REAF Officer, Flt Lt P V S Ram – Ferry of the first Toofani aircraft in the IAF on October 1953.

Laurels with HAL

While the Folland Gnat was still under development, Dasu had just been given command of 3 Squadron at Ambala and was asked to join the Folland star team of Mike Oliver, Ted Tennant, Maurice Carlisle and Dick Whittington. His critical inputs, especially in adapting to tropical flying, subsequently helped the aircraft earn its moniker of Sabre-Slayer. He also became the first Indian to demonstrate an aircraft at the Farnborough Air Show, the Gnat itself. After returning to India in 1958, Dasu took charge of the Aircraft and Armament Testing Unit (A&ATU) at Kanpur (now called  Aircraft & Systems Testing Establishment, the premier experimental testing establishment of IAF), overseeing the development and operational induction of the Gnat into the IAF. With the job done, Dasu’s expertise was again sought by HAL, and to where he moved as the Chief Test Pilot in 1961, by this time he had amassed 1,000 plus flying hours on more than 35 aircraft types.

It was his flight testing with HAL that went on to earn him laurels. He was also travelling the road not travelled by any IAF pilot before him. During his stint with the HAL, Dasu’s most historic flights included the maiden sorties of the Indian designed and manufactured HF-24 Marut on 17 June 1961 and the HJT-16 Kiran, on 4 September 1964. While the Marut went on to play a role in the 1971 War, the Kiran trainer continues to fly in the IAF even today. As the IAF sought to graduate to the supersonic era, Dasu was involved in evaluating the English Electric Lightning, Mirage IIIC and MiG-21 FL aircraft. After being involved in the selection and development of the famous Gnat, Dasu gave a thumbs up to the IAF’s next iconic fighter aircraft – the MiG-21 FL.

After the second flight, 24 June 1961, U/K, MD-HAL, Dr Bhagwanthan, Suranjan Das, VKK Menon (Defence Minister) Mr Iyengar, Prof Kurt Tank, Air Mshl AM Engineer (CAS), Homi Bhaba, and Mr Das (Chief Aerodynamicist).

‘The mighty mouse’ and slow-cooked salmon

Like all brilliant minds, Dasu liked to potter around too, be it in his garage, workshop or in his kitchen. A keen and accomplished aero-modeller, Dasu had created a 2-stroke engine in his home workshop called “The Mighty Mouse” and had also souped-up his two-seater MG car. He also had a special fondness for guns, carefully maintaining and polishing each of his firearms before putting them on display. His displays also included various hunting trophies including those of a tiger, a crocodile and a bison. Dasu was also a keen angler, having cast his fishing rod in some of the most popular rivers and streams of the country. Always keen to share the bounties of the wild, Dasu used to cook the game himself, mostly on a reappropriated oil drum rigged with a blow torch to control the flame. It is said that a slow-cooked bhekti or salmon, served with a buttery lemon sauce, was one of his most famous dishes. Between all these hobbies and test flying, he also found time for some philanthropy.  His contributions to the Cheshire Home in Bengaluru have been commemorated in the form of a special wing that has been named after him.

Married in 1947 to Binita Das and divorced later, he would find love during his time in Chilbolton, UK, when he met Veronica Loveless MBE (Member of the Order of the British Empire). His sense of humour and easy-going attitude endeared him to colleagues, contributing to a very close-knit brotherhood of test fliers in the 1950s and 60s.

Suranjan Das after fishing.

Dasu will always be remembered the most for his contribution to the development of the HF-24 Marut – India’s first homegrown fighter aircraft.  Designed to be a supersonic fighter, the Marut was powered with two non-afterburning Bristol Siddeley Orpheus 703 turbojets – the same engines as on the Gnat. However, the aircraft could not reach its true potential for want of more powerful engines. It saw service with the 10, 31, 220 Squadrons and Air Defence Flight. The aircraft had some modest successes in 71 war and flew 127 sorties, attacking airfields, railway routes and even a claimed shooting of a Pakistan Air Force Sabre, earning its pilots three Vir Chakras.

But before its disappointing phase-out, the Marut claimed the life of Group Captain Suranjan Das – the man who had been awarded the Ati Vishisht Seva Medal for his contribution to the development of the aircraft.  On 9 January 1970, just shy of his fiftieth birthday, Dasu lost his life during the first test flight of the after-burning variant of the aircraft’s Orpheus engines as the canopy unlatched during take-off and prevented the aircraft from gathering sufficient speed, crashing shortly after. Awarded the Padma Vibhushan posthumously, Group Captain Suranjan Das remains the paragon that all Flight Test crew of the IAF aspire to be.  Every year, the trainee adjudged the best in the IAF’s Test Pilots School is awarded the Suranjan Das Trophy. He and his fellow graduates then endeavoured to tread on the path of ‘precision and excellence’ (motto of the Test Pilot School) – one which had been so well travelled by Dasu.

This is part of a series on military biographies.

Anchit is an aviation historian and tweets at @anchitgupta9. Views are personal.

(Edited by Srinjoy Dey)