Tuesday, August 29, 2006

Group Capt Suranjan Das 1920-1970

After Maiden flight of HF-24
Group Captain Das sitting in the cockpit of a Folland Gnat

Maiden flight of the HJT-16 Kiran on September 4th 1964

Suranjan Das - the man and the professional
By Gp Capt Kapil Bhargava (Retd)

Group Captain Suranjan Das was one of the two pioneer test pilots in the Indian Air Force (IAF). Born on February 22, 1920, he grew up to be a boy whose gaze was forever skyward. However, dissuaded by parents who did not consider their boy good enough to be a pilot, he joined an engineering college. But then came World War II. The young man volunteered and was selected as a trainee pilot for the Royal Indian Air Force (RIAF). He learnt to fly in Canada, earned his wings as a pilot and was commissioned into the RIAF in 1943. His parents, and assorted aunts in the joint family, declared that if he could get his wings, they could not be very difficult for anybody to get. He joined No 8 Fighter-Bomber Squadron. A colleague from his early days remembers that he was a bit “ropey”, especially in close formation. But he was a wizard with solving technical problems, which the squadron’s engineering staff could not handle. In 1947-48 he participated in operations in Kashmir. He grew into flying and went on to take his place firmly in the history of flight testing and development of new aircraft types.

The year 1949 was a watershed for the aviation industry in India. In that year Dr VM Ghatage started design work in Hindustan Aircraft Limited (HAL) on the Hindustan Trainer-2 (HT-2). At the same time, IAF felt the need of test pilots and sent two brilliant pilots to Empire Test Pilots School (ETPS) in the UK. They were Flight Lieutenants Roshan Lal Suri and Suranjan Das. Flt Lt Das, popularly known in the IAF as Dasu, was deputed to HAL to accept license produced Vampire jets on behalf of IAF. HAL realised that it needed a qualified test pilot to assist the development of the HT-2 and Dasu was earmarked for the job. On August 5, 1952, Mr Jamshed K Munshi, HAL’s Chief Test Pilot (CTP), while taxying the HT-2, got airborne in it and flew it for about 45 minutes. After he landed, he pronounced the aircraft fit for the IAF. Dr Ghatage asked him if he had spun the aircraft. Captain Munshi confirmed that the aircraft had given him no trouble in the spin. He left HAL soon afterwards.

For meeting Service requirements, full-scale spinning trials were planned. Dasu demanded that an anti-spin parachute be installed - that is what he had learnt at ETPS. He was told that this was not necessary, as Mr Munshi had already spun the aircraft. Dasu then negotiated his briefing. He said that he would do two turns after entering a spin and then take standard recovery action. If the aircraft did not recover after four turns, he would bail out. That is exactly what he did, Southwest of Yelahanka village. During debriefing Dr Ghatage alleged that Dasu had bailed out only to prove his point. This was perhaps the only known occasion when Dasu lost his temper. It took many flight trials to clear spinning on the HT-2. Even till the end of its service, spinning the aircraft remained somewhat critical. Full down elevator was usually needed to recover if the instructor in the back was heavy, with a light cadet in front - a natural result of their age difference.

The IAF acquired Ouragans, named Toofani in India, from France. The first 75 dismantled aircraft were brought to Bombay on a French aircraft carrier. These were unloaded and taken to an allotted area at Santa Cruz airfield, which was the home of the Aircraft Erection Unit (AEU) – the first such venture by IAF. In 1953-54 Dasu commanded this unit and proceeded to flight test and clear each aircraft as it got ready. Other pilots of AEU to assist in the flying effort remember Dasu as always being full of fun and yet conducting and ensuring flight tests to very exacting standards. The Ouragans were ferried to Kanpur to await raising of Toofani squadrons. At Kanpur, Dasu hit a blue-bull on the runway during a take-off, killing it. The Toofani also suffered considerable damage but was repaired for flying. Fortunately, Dasu was not injured.

In 1954, Air Cdre PC Lal (Later Chief of Air Staff), led a team to select aircraft to supplement and then replace Vampires and Toofanis. The team had both Suri and Das as its members. Sqn Ldr Bhupinder Singh who had qualified as a test pilot a little earlier replaced Dasu as the CO of the AEU. While in France, Dasu took up a well-instrumented Mystére IV to put it through its paces. At about 500 knots at low level, the aircraft got into violent longitudinal oscillations during which it exceeded its limit of 7G by a big margin. Flt Lt Jacob Chacko, an eminent engineer, was a technical member of the evaluation team. He had also earned his wings in IAF. He suggested the solution to this behaviour. A damper, called a dashpot, was put on the longitudinal control circuit to reduce the chances of a pilot inducing the oscillations. This worked well and made the aircraft acceptable. In France Dasu also flew the Vautour fighter-bomber aircraft. After moving to England he evaluated, along with Roshan Suri and the technical team, the Swift, Hunter, Canberra and Midge. The latter was the forerunner of the Gnat. In Sweden the two test pilots evaluated the SAAB Lansen. The IAF eventually acquired four of the aircraft types recommended by the team.

When IAF decided to go in for the Gnat, evolved from the Midge, Sqn Ldr Das was attached to Follands at Chilbolton in England. During his tenure at Follands, Dasu took very active part in the development of the aircraft. He also became the first Indian to demonstrate any aircraft at the Farnborough Air Show. Once while practising for it, he was doing an eight-point roll in the Gnat close to the ground. He suddenly felt a restriction in the aileron control. His first reaction was to start talking on the radio. He asked the Air Traffic Control to ensure that his comments were recorded just in case he could not recover. He said that these could help prevent a recurrence of the problem. The Orpheus engine, which powered the Gnat, had a strong tendency to flame out due to surge at high altitudes and the associated low temperatures. This behaviour also had to be cured. Dasu used to say only half jokingly that he had more gliding hours on the Gnat than with its engine running. At Chilbolton, he met Veronica Loveless. They eventually got married in Bangalore in November 1961.

Dasu returned to India and took over command of the Aircraft & Armament Testing Unit (A&ATU). A special handling flight was raised at A&ATU to ensure the safe induction of Gnats into the IAF. The Gnats still had many problems which were eliminated only after A&ATU found the solutions to them under Dasu's leadership. Prominent among these were the engine flaming out on gun firing at medium and high altitudes and empty shells striking the tailplane. The flight control system was over-sensitive and made it impossible to fly the aircraft in formation. This problem was solved after the gear ratio of the stick to the elevator was reduced substantially. After the war with Pakistan in 1965, Gnats came to be known as Sabre Killers.

In 1954-55 Willy Messerschmitt and Kurt W. Tank offered to develop a fighter aircraft in India. HAL chose Prof. Tank as the more able designer for a multi-role aircraft. He came to Bangalore with a seventeen-man team which soon dwindled to thirteen. His aircraft was allotted 24 as its design study number and was named Hindustan Fighter-24 (HF-24). Tank had great faith in gliders and decided to make a full-scale plywood flying model of the aircraft. Wg Cdr Roshan Lal Suri as the senior most Indian test pilot came and took over as Chief Test Pilot (CTP) of HAL in time for the project. He did 83 successful launches in the glider. (See Indian Aviation August 10-16, 2001). Unfortunately, Roshan Suri did not plan the first take off on the HF-24 fighter aircraft adequately and aborted it with undercarriage up on the ground. Wg Cdr Suranjan Das replaced him and carried out its successful maiden flight on June 24, 1961.He also did many of the subsequent development flights on the aircraft. The aircraft served in the IAF, including during the 1971 Bangladesh War. It was retired mainly due to its very complex production procedures and the inability to ensure prompt supply of spares which were also difficult to produce.

In the summer of 1961, Wg Cdr Das and Flt Lt PK (Babi) Dey evaluated several aircraft types for induction into IAF. These included English Electric Lightning, Mirage IIIC and MiG-21 FL. The Russians did not expect Indian pilots to fly the aircraft before selection. Dasu told them informally that if the aircraft was too difficult to fly, perhaps it was not suitable for the IAF. Russian attitudes changed immediately and the aircraft was tested by both the Indians and chosen for import and indigenous manufacture. Hundreds of these were manufactured at HAL's Nasik Division and even today are the backbone of the IAF. Dasu also did the first flight of the HJT-16 (Kiran) on September 4, 1964. The Kiran is the mainstay of IAF's intermediate level training of new pilots. Wg Cdr IM Chopra, who joined HAL as a test pilot and retired as its Chairman, remembers him with fondness. According to him Dasu was an excellent boss to work for. He was easily approachable and would listen to a subordinate’s ideas with attention and due respect. If they were worthwhile, he would ensure that they would be implemented, and credit given where due.

Dasu the man was as accomplished as the professional. He was never one to let a day pass bye without extracting some joy out of it. This, for him, meant involving himself in some pet project. He would add an engine to a cycle and call it the 'Mighty Mouse' and explore the countryside in the UK astride it. An abandoned heap of a car was turned into a brightly painted racing car in his expert hands. Guns were his passion, which he would rarely use but polish lovingly and put on display. He fashioned the wooden butts of his guns in his own home workshop. They were works of art. He was very fond of cooking and was really good at it. He could have easily bagged a job as a chef in a good hotel if ever he felt like it. Dasu was a keen aero modeller. He participated actively in the HAL Aeromodellers' Club. Even so, the most remarkable aspect of this obviously accomplished man was his unassuming manner and amiability, which earned him respect, both as a man and as a professional.

Gp Capt Das as the CTP of HAL was the driving force for follow-up versions of the HF-24, named Marut in IAF. He did extensive flight testing of the HF-24 Mk1R with reheated Orpheus engines on it. Equipped with modern avionics. this would have been a strong competitor to the SEPECAT Jaguar. On January 10, 1970, the brilliant career of Gp Capt Suranjan Das came to an untimely and tragic end in the fatal crash of the HF-24 Mk 1R prototype. On take-off, the canopy opened and probably the right engine lost power. Unfortunately, he could not have ejected out of the aircraft unless the canopy flew off, which it didn't. At that time his father, the ex-Chief Justice of India, was the Vice Chancellor of Vishwa Bharati at Shantiniketan. He was naturally very sad at the irreparable loss and yet very proud of his son. Dasu’s death killed the 1R project.

For his invaluable contribution to the country in its quest for indigenous production of aircraft, Gp Capt Suranjan Das was awarded the Padma Vibhushan posthumously. A road in Bangalore connecting HAL’s main Complex to the Engine Division also commemorates him. HAL instituted a trophy in his name for the best test pilot trainee graduating in India each year. The graduation dinner is also named after him. Mrs Veronica (Twinx) Das has been an honoured guest at each of these dinners so far. She is eminent in her own right as a social worker. As a volunteer, she served on the Executive Committees of the Deaf Aid Society and Bangalore’s Cheshire Home for many years. She is now the head of the Cheshire Home, a part of the Leonard Cheshire International. She was awarded the Order of the British Empire in 1997 for dedication to charitable work in India.

Gp Capt Suranjan Das' name stands for excellence in the profession of test flying and is an inspiration to all those who aspire to contribute to India's development in aeronautics.