New taxiway for faster take-offs

KOLKATA: Amitava Basu was booked on Jet Airways morning flight to Mumbai on December 2008. Bad weather forced authorities to suspend operation at the airport for three hours that morning. Finally, Basu managed to board his flight and the aircraft door closed 2 hours behind schedule. But congestion at the runway led to a further delay of over 30 minutes.
Basu's travails are set to end with Airports Authority of India planning to inaugurate a new taxiway that will reduce runway congestion and hasten takeoff by 20-45 minutes."Once this new taxiway is opened, the runway occupancy time will come down from 4 minutes to 2 minutes," said Kolkata airport GM (operations) Mahesh Kaul.
The new taxiway, christened kilo-taxiway, will connect the end of the secondary runway to the primary runway just ahead of takeoff run at the Madhyamgram end. "We will commission the new taxiway in two days. It will save nearly Rs 3 crore per month in operational and fuel cost," said airport director R Srinivasan.
Currently, the airport has four taxiways A, B, C and D (see graphic). To take off from the Madhyamgram side (19L) of the 11,900 feet primary runway, an aircraft has to taxi from the parking bay through taxiway A. The take off distance from taxiway A to the Rajarhat end of the primary runway is 7,100 feet which is enough only for ATRs, other small aircraft and narrow body planes that weigh less. Wide body and fully-loaded narrow body aircraft have to backtrack and taxi another 3,000 feet till the Madhyamgram end of the runway, do a U-turn and then start the takeoff run.
Airline officials said narrow body aircraft with full load need over 8,000 feet for comfortable take off. The new kilo taxiway is so located that it will allow aircraft a 10,000-ft free take-off run without having to back-track.
"This will reduce the runway occupancy time by almost 50%. The time will fall further if a narrow body aircraft is followed by an ATR. Then the separation time will be a minute and the ATR can take off from the intersection of taxiway A," said an ATC official.
However, fully loaded wide body aircraft will still have to backtrack. "Kolkata airport doesn't have a cluster of wide body aircraft operating at the same time. So, we don't expect a major problem as of now," said Airline Operators' Committee vice-chairman (operations) Sudipto Chandra.
Even when only the secondary runway is in use, the new taxiway will expedite departures. At present, departing aircraft cannot taxi into position till the runway is clear. Once the new taxiway is in operation, departing aircraft can quickly move to primary runway and take up position at the kilo-taxiway that is at the far end of the secondary runway.