New 'bird' in sky to help reduce flight time

By 2010, a flight from Delhi to Chennai could take just two hours, a full 45 minutes less than the current duration. And a Mumbai-Delhi flight could be only an hour.

This anticipated saving in time and money (in terms of fuel costs and airport charges for carriers) will be possible with the launch of GAGAN, or the satellite-aided geo-augmented navigation project being jointly implemented by the Airports Authority of India (AAI) and the Indian Space Research Organisation (ISRO).

A Rs 644-crore project to implant navigation software in existing satellites, GAGAN, which is currently undergoing feasibility tests, will do away with the need for aircraft to be navigated through ground navigation stations, which now send position signals to the aircraft.

When the project is implemented, the signals will come from the satellite to reference stations across the country, get corrected by them and uplinked to the satellite, which will then transfer the accurate signals to the aircraft. Apart from accuracy in position, the aircraft will be able to plot its way through much shorter routes.

In the current system, routes are determined by the location of the ground stations or aids, which are usually 150 km apart. So a Delhi-Chennai flight currently takes a zig-zag route over Farukhabad-Secundrabad-Banaras-Bhopal-Nagpur-Hyderabad-Chennai.

In time, the 80 air control towers across the country will be replaced with eight reference stations at Delhi, Kolkata, Guwahati, Port Blair,

Ahmedabad, Bangalore, Jammu and Thiruvananthapuram, with a master control centre in Bangalore. Later, eight more stations and two more control centres might be set up in Bangalore and Delhi.

Civil Aviation Minister Praful Patel hopes to introduce GAGAN in a limited way next year and the full system by 2010.

Importantly, shorter flying time will maximise the use of air-space, allowing more flights to take off and land at airports.

The current specified gap between two airborne aircraft is 80 nautical miles in length and 10 nautical miles on both sides in width as a safety measure to account for a margin of error in air traffic control information.

For instance, an aircraft receiving signals that it is near Jamshedpur may actually be 50 miles behind or ahead. With GAGAN, positional accuracy improves to 95 per cent, allowing the gap to be reduced and making room for more aircraft.

"Due to the decrease in width, one airspace lane may be divided into two or even three. Also, in regions with heavy traffic, we may divide the space into several speed lanes for different aircraft with different speed capabilities," said an AAI official.

Shorter flying time will also reduce fuel costs. The average fuel burnout for a flight per hour is 3.3 kl. Saving around one hour of flying time will shave off more than Rs 1,20,000 per flight considering jet fuel in India is priced at Rs 37,800 per kl.

Airport charges will also fall. "Due to all these changes, the route navigation facility costs for airports will fall. Consequently, the route navigation facility charges for airlines will also come down significantly," AAI officials said.

These are major gains, given that India has the second-highest airport charges in Asia. The charges are also several-fold higher than American and European airports.

The system will also mean major savings for AAI. Operating and maintaining these ground stations costs it Rs 40 lakh a year. With GAGAN, around 60 air traffic control centres will be phased out, which translates into a saving of Rs 24 crore annually.

But airlines have reservations about installing GAGAN-compatible equipment. "Most new aircraft are equipped with the retro-fitted global navigation satellite system (GNSS) avionics, which is necessary to receive the accurate GAGAN signals. But aircraft that are more than 10 years old do not come equipped with the system," said an airline official.

For aircraft like the old Airbus A-320, retro fitting the system will cost around Rs 15 crore. This will particularly impact the government-owned Indian Airlines.

"Many airlines will not be able to shift to the new system so easily, which is why the transition will be in phases and take two or three years to be fully operational," said an AAI official.