Reaching for the Skies

  • 14/11/1994

Reaching for the Skies THE Indian skies are not as generous and capacious as they appear to be in the rosy light of touristy optimism when it comes to accommodating the steadily increasing domestic and international aircraft flights. The "airport stress syndrome" has come to roost in India, following its establishment as the hub of burgeoning air traffic in the newly open Asian market. To cope with the attendant problems that congested airways engender, the Union government has launched an ambitious Rs 1,350 crore plan to modernise the country"s air traffic management capabilities.

On the horizon is a fascinating mix of space, electronics and computer technologies before which the current machinery and practices of the National Airports Authority (NAA), responsible for all civil air traffic control in India, appear stodgy, if not superannuated. Says NAA chairperson A M Bharadwaj, "By the time our plans are fully operational, air navigation in the country will have undergone a major metamorphosis."

The current year has seen much low-key, yet urgent, activity towards initiating this change. Beginning this February, the NAA in collaboration with the International Civil Aviation Organisation (ICAO), has been conducting a trial project for the detailed surveillance of inbound flights from the Southeast, using information generated by the International Maritime Satellite Organisation (INMARSAT).

Then, in September, various national and international civil aviations sent high level delegations to India to get information about the initial findings of this project. Its apparent success led the Union civil aviation ministry to send a hardheaded delegation to Montreal last fortnight, where talks were being held under ICAO"s auspices for the augmented sharing of aviation-related satellite information. High-powered groups of aviation experts and technocrats have been putting the finishing touches to other elements of the comprehensive plan, which has come to be known as the Future Air Navigation System (FANS), to be operational by AD 2010.

Experts point out that this broadbased effort could not have come too early. Air navigation arrangements in India have been under stress since the "80s due to increasing traffic as well as growing obsolescence of its technological and managerial systems.

Overall air traffic over India has shown a 5 per cent annual growth rate since the beginning of this decade, and the NAA estimates that the rate will climb to 8 per cent from 1996. In actual numbers, the increase in projected flights through India may be even more astounding.

The reasons for heavier air traffic are both national and international. IATA spokespersons stress the latter, explaining that "India is strategically based at the confluence of the East and West air corridors". Most aircraft commuting between Europe, Africa and West Asia, on the one hand, and Southeast Asian countries such as Korea, Singapore or Malaysia, on the other, fly over India. Since the mid-"80s, this category of air traffic has increased remarkably, mainly propelled by the strong economic growth of the so called Asian Tiger Group of countries.

Operations extended
Within India, a marked extension of operations network by Indian Airlines and the proliferation of other domestic airlines has contributed significantly to the number of domestic flights. NAA projections put the number of civil aviation planes deployed by Indian companies by AD 2010 at 338, up from 152 at present.

Moreover, the increase in numbers is not evenly spread over the entire available daily flying time. International traffic, in particular, tends to be bunched in a few choice hours at night. The most important reason for this crowding, ironically, is enhanced environmental consciousness about international traffic over India in several countries of origin or destination (typically, the United Kingdom and France in Europe, and Hong Kong, Singapore or Australia in the East), which has manifested in green laws prohibiting noise pollution from rising above specified ambient levels at night. Most air travel and transport in these countries is conducted during the day, inevitably transiting through India at night.

Says Director General Civil Aviation H S Khola, "All aviation traffic exercises in India have to take note and accommodate these night curfews in developed countries in the West as well as in the East." Even NAA authorities share this assumptive attitude. "Do you think there is anybody to protest about noise here?" asks Bharadwaj jocularly.

In the face of this increased load, there are several manifestations of the operational limitations of the country"s air traffic systems and procedures. The first is the comparably inefficient handling of air traffic. Pilots of international airlines charge that they have to adopt unnecessarily slow approaches over the last 150 nautical miles (nm: 1nm = 1.8 statute miles) as they prepare to land in India. Says a British Airways pilot, "In comparison with airports in Europe or North America, we take as much as 15 minutes longer in landing in Delhi or Bombay."

The delays imply higher fuel consumption costs. The problem recurs when the planes do not receive permission for optimum flying levels. For example, the Boeing 747, favoured by most airlines for long distance passenger flights, needs to travel between 37,000 to 42,000 feet for optimum fuel efficiency at its cruising speed. Pilots reveal that they have often traversed 300 nm after takeoff before obtaining permission to enter such levels. The problem often cascades. Due to placement in suboptimal levels, most aircraft maintain slower speeds, and takeoffs form airports are, therefore, slower.

That this is due to higher traffic hardly evokes any sympathy from international aviation operators. They argue that many countries all over the world have begun to manage far denser air traffic much more efficiently. True. The Indian air traffic control system aims to maintain a time difference of 15 minutes between any 2 aircraft on the same flight level while superior air space programmes elsewhere have lowered this to 5 to 3 minutes.

Controlling traffic
On their part, the air traffic controllers (ATCs), trained and employed by the NAA insist that they have to maintain much larger buffers of time and space between aircraft because of a crucial characteristic of the systems they use. Says H M Shahul, member (operations), NAA, "Currently, our traffic controllers operate with reasonable approximations of aircraft positions, speed and direction, which, while normally very close to actuality, do call for much wider safety margins." He points out that a traffic system for much denser, high speed air traffic would call for a more precise generation and exchange of relevant data.

In contrast to popular imagination, large bits of civilian air space in India are outside radar surveillance. The minor airports, typically those catering only to domestic traffic, are equipped with radars that have a range of 60 nm. Other than Nagpur, only the international airports are equipped with more powerful radars having a range upto 200 nm.

As even the latter ones only display positions of various planes as uniform blips, even the most experienced of ATCs do not rely upon them during peak hours. "When you see 20 to 30 spots of light moving all over the screen, without any other identification, it is easy to get confused," says a senior ATC at Delhi"s Indira Gandhi International Airport. Like other ATCs, he prefers to guide in aircraft through communication with the pilot and manual computations of their positions and speed, and using these to even resolve "conflict" situations. Through training and experience, the ATCs have become rather good at this but they admit that the current traffic loads are already taxing their capabilities to the limit. "On busy nights at peak hours, the tension is almost asphyxiating," says J S Ahuja, Deputy Director (Aerodrome), at IGIA.

Away from the airport
Further away from the approach area of the airports, the degree of approximation in various navigation and surveillance operations increases. Other than messages from ground-based controllers (who basically check off the aircraft against the speed and direction parameters filed in flight plans), the aircraft rely principally on directional beacons sent up by 60 Very High Frequency Omni Range (VOR) transmitters, located throughout the country. In real terms, high performance aircraft hop from beacon to beacon. Thus, all traffic between Delhi and Bombay swings over to Udaipur because a connecting VOR is located there. And because geographical features around the VORs can affect the VOR transmissions, air routes between them are necessarily very narrow, a feature which amplifies the problems of increasing traffic.

Says Khola, "Only a multi-pronged systematic initiative can offer a solution to the range of problems." He points that the first element of the concerted action plan, finalised this year, consists of increasing the number of VOR sites in the country to 80 by 1994. By itself, the measure would enable shorter routes in a number of sectors.

Besides, major airports as well as select groundstations are to be equipped with a contemporary generation of radars called the Monopulse Secondary Surveillance Radar (MSSR). G M Apte, Member (Planning and Engineering) of NAA reveals that the these "sites are being chosen with a view to enable the surveillance of all aircraft flying above 12,000 ft." The MSSR equipment also enables generation of more user friendly information. For one, it automatically generates an identification tag on every target it is tracking, a facility which may go a long way in encouraging the ATCs to depend on the system. A very high frequency communications network is to be established between the MSSR sites.

Equally important, a large range of operations currently carried out manually by the ATCs are to be computerised. To facilitate this exchange, the NAA plans to introduce 2 softwares -- the Flight Data Processing System and the Radar Data Processing System. Says K V N Murthy, executive director (planning), NAA, and a key member of the multi-agency team considering air traffic modernisation, "Linked to the VORs and the radars, these will enable the ATCs to have much more detailed information of all aircraft in the region." The 2 softwares would enable ATCs to constantly update flight monitoring, predict points on routes, and solutions to all airspace conflict problems that may arise.

Aviation experts feel that these features will enable air traffic controllers to halve the time and space separations that are currently the standard. "It is reasonable that these measures will enable us to match air traffic norms that are prevalent worldwide," says Apte.

But this is not going to be all. Aviation planners in the country are looking for even more futuristic technologies. "Only satellites can provide the basis to any approach to air traffic control that will remain valid late into the next century," says Bharadwaj.

A satellite-based solution has been found to be attractive on a number of counts. According to Khola, the first of these is that modelling of desirable and adequate coverage of the numerous "thin traffic regions in the country" through ground-based systems is cost ineffective. Hilly and mountainous terrain is considered to be particularly problematic. Also, more than 50 per cent of the Indian airspace is over oceans which are much better covered by satellite-based surveillance.

With this conviction, Indian civil aviation authorities plan to begin next year the installation of equipment, valued at over Rs 950 crore, which would enable ATCs to tap directly into the global satellite navigation infrastructure being currently created under FANS.

There are 2 key elements of FANS. A constellation of observation and communication satellites, called the Global Satellite navigation System, will offer instantaneously updated positional information of all aircraft in the air anywhere in the world. This information can be relayed to any aircraft as well as air traffic control stations through the Aeronautical Mobile Satcom System (AMSS).

Using information processing systems being installed by the NAA, the aircraft and ATCs will be able to resolve all conflict situations, have a range of flight track options with the ability to choose the one that is the most fuel efficient. A detailed report prepared by the NAA concludes that it would be possible to improve fuel efficiency of domestic operations by as much as 5 per cent using satellite based navigation. Air safety is estimated to increase by a factor of 10.

On the negative side, the FANS scheme will render VORs and much other equipment exclusive to ground-based navigation obsolete, on which nearly Rs 200 crore is to be spent by 1996. Even so, the national aviation authorities have made up their mind that this expenditure would be worth it. They feel that the domestic operators must be given time to install satellite compatible equipment and till then would have to be provided with adequate navigation and surveillance services. Says former civil aviation secretary Sovan Kanungo, "These are the constant dilemmas of technology in a developing country." He headed the committee which opted for this 2-track approach.

Other issues are not so easily taken care of. Programmes to upgrade training of ATCs to enable them to deal with high-tech systems of global capability are yet to be worked out. Many airline managers are not certain whether they would be able to afford the required satellite capable equipment, or of its advantages to their fixed operations. And, just by the way, Indian authorities have not bothered to be as zealous about a less glamorous international proposal to consider the environmental aspects of large airports. For the time being, they are flying high on plans for airways of the future.

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