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Preamble:
Recent Iran war has shown how vulnerable we are as an economy, when oil prices go up. Even the Rupee has to depreciate considerably against the dollar and the PM had to advice public to cut on various imports. Civil Aviation is one sector, where we import both the aircraft and the oil, perpetually. Look at the projections of the planned aircraft imports over the next decade, which is of the order of a whopping Ninety Billion Dollars. Hence, there is a definite need to review this sector, for necessary tweaks.
Aatmanirbhar Bharat:
In the changed geopolitics, Aatmanirbhar Bharat has become a necessity. Can a country with ever increasing air travel afford to completely depend on imported aircraft even for internal travel, leave aside international travel? Against this background, can we do something to have an indigenous civil aircraft, at least for internal travel?
Technology:
With successful development of a 4.5+ generation fighter aircraft ‘Tejas’, we do have the requisite technology in the country, to develop a civil aircraft.
What are the Challenges?
The most challenging aspect in the case of a civil aircraft is its commercial viability. In this context, it is foolhardy to think that we can ever develop a narrow body aircraft, which can compete with well-established aircraft such as A320 Or Boeing 737. Since, ours is a very cost conscious ecosystem, our aircraft has to be fuel efficient by at least 15-20%, against these aircraft, for it to succeed even for our internal travel.
How do we achieve such a significant saving in fuel burn?
Post superannuation from ADA, I happened to be part of the feasibility studies conducted at NAL, for a Regional Transport Aircraft of size 90-110 seats, under a High Powered Committee headed by Dr Madhavan Nair. In addition to my technical role, I was focusing on Business Model for the aircraft. Post feasibility studied & submission of the report, I did continue my research to figure out what is really the best aircraft spec, for Indian ecosystem, with a capability to pinch at least some established market share, for internal travel. My studies indicated that the narrow body aircraft currently in use are not really fuel efficient, when it comes to sector distances below 450NM, such as Bangalore-Mumbai and lower. Most of the flying time is spent in take-off, climbing to the requisite altitude of 33,000ft and come back for landing, with hardly any cruise at the rated speed of 0.78M. Hence, in reality they are not apt for such sectors, where their rated fuel efficiency is not properly exploited. Hence, any aircraft developed by us should target such shorter sectors.
It is a well-established aerodynamic fact that the drag (in turn fuel burn) would be minimum for an aircraft designed to suit the speed range of 0.5 to 0.6M. If we choose such a rated speed, the aircraft configuration also becomes simpler (without a Wing Sweep and the need for Slats), making it economical for manufacture. The time penalty in using such a low speed aircraft will not exceed fifteen minutes, for a typical Bangalore-Mumbai sector. It should not be a concern, against a cheaper air-fare, particularly in Indian context. Such an aircraft will be even more attractive in shorter sectors such as Bangalore-Hyderabad, Bangalore-Chennai and etc. Such an aircraft will be apt for about 70% of the currently established internal sectors/routes in India, making it commercially viable.
What should be the size of such an aircraft?
Based on the literature survey on fuel consumption per seat, the requisite savings in per seat fuel consumption can be achieved only with a minimum capacity of 130 -150 seats. Such a capacity calls for a five-abreast seating, leading to an ideal circular cross section for the fuselage, while meeting the standard height requirements for the passenger and luggage cabins. Also, circular section is strength efficient, from structural weight point of view.
Type of aircraft:
Typically, low speed aircraft of 0.55M are Turbo-props, operating at about 22,000 ft altitude. Till a decade back, with only ground based navigation in vogue, clearly demarcated the routes were in place for aircrafts to fly, between any two places. Accordingly, only 0.78M rated speed jet aircraft were permitted to fly at 33,000ft and 0.5M rated turbo-props at 22,000ft. However, with the introduction of satellite navigation in India, such a restriction can be removed and the same was confirmed by the Airport Authority of India reps, in one of our interactions. Which effectively means that they can have more than one lane at 33,000ft, to permit aircraft of different speeds. They can also give altitude spacing. Hence, a low speed aircraft of 0.55M can in principle fly both at 22,000ft as a turboprop or at 33,000ft as a turbojet, opening up more options for aircraft specification.
New-generation turboprop engines, offering the requisite fuel efficiency for such an aircraft, are not yet available in the international market. However, one can find several new generation turbo-fan jet engines, which are extensively used in international market for regional jets. Also, during our studies, engine manufacturer Pratt & Whitney reps did confirm that the existing Turbo-fan engines can be comfortably used for lower cruise speeds, compared to designed spec of 0.78M. Which effectively means that getting a Turbo-fan engine for the proposed aircraft is just a matter of selection among the available, maximizing the size. Developing a new generation turboprop engine specific to us can cost enormously, adding to the project costs and development risks. Hence, while the conventional wisdom points towards a turbo-prop, we may be better off in going for a turbo-fan, as a way forward. But, it would be an out of box solution just meeting the Indian domestic travel requirements, until the satellite navigation is adopted universally. The positive side is that the attendant risks of structure specific noise & vibration due to propellers of a turboprop is altogether avoided.
Recommend Specifications for Indian Civil Aircraft:
While what is presented here may look simple, it is well neigh impossible to find a better alternative, for Indian market & its ecosystem. It is arrived after extensive literature studies & thought process on civil aircraft and the economics which drive it for a success, in Indian market. The challenge is more like a new car entering into market for success, with very few achieving it.
A civil aircraft with Rated Speed of 0.55M, Range of 450NM, with a minimum seating capacity of 130-150 (the higher it is better), Five-abreast circular fuselage, Wings without Sweep & Slats and with an available turbo-fan engine maximizing seats.
How do we go about with the project?
It is suggested that leading private enterprises, such as Tata, L&T, M&M etc, with requisite technology back ground can be encouraged to explore the possibility of initiating such a project. They can easily get a Delta Feasibility studies done by IAI, Israel, who had earlier conducted a parallel study for CSIR-NAL, at that time. The study can be initially limited to engine choice for maximizing seat capacity, aircraft configuration broadly meeting the objectives, estimation of the aerodynamic performance and in turn the fuel burn per seat, for 200-450NM range sectors. IAI may also give a spec for a turbo-prop engine and the corresponding fuel burns, if an engine has to be ever developed. Commercial viability studies can follow, with involvement of existing civil aircraft operators in the country.
Creation of a Joint Venture for the project:
The whole exercise of development and production can be in a joint venture mode. Since it helps Aatmanirbhar Bharat goals, government can create a joint venture with private sector (having 51%) and offer an R&D grant twice the equity, incentivizing the private sector to come forward, for such a development. Only condition, that the grant should be spent proportionate to equity, to ensure responsible spending.
A 2,000Cr equity plus 4000Cr R&D grant could be sufficient. It is a ballpark figure and someone like TATAs can even achieve the goal at a lesser outlay, given their established infrastructure in aircraft related manufacture and also experience from running a huge commercial airline such as Air-India. They can easily employ a foreign design house, being a one-time exercise, with an experienced design specialist team of theirs monitoring. The Government of India is also expected to form an expert team to review the project, from time to time, involving expertise at NAL, ADA & HAL, as an oversight body, for constructive criticism and advice if any.
When this project succeeds, it is expected to be a money spinner, in addition to saving enormous foreign exchange. It will be another feather in the cap of the country, on lines of Tejas.
Dr K Sham Sunder
Outstanding Scientist & a former Project Director of ADA
These pieces are being published as they have been received – they have not been edited/fact-checked by ThePrint.