Fog-beater on second runway too

KOLKATA: Thursday turned out to be a lucky day for the city airport. While the integrated terminal finally got a date on Thursday for its inauguration, the category I instrument landing system (ILS) too became operational on the same day, 19 months after it was installed in June 2011. It means planes can now land on the secondary runway when the fog isn't too thick.

The primary runway at the airport does have a more advanced CAT-II ILS version, which allows flight operations till visibility drops to 300 metre, at both ends. But airport management had a tough time shutting down the runway for maintenance during winter as absence of ILS on the secondary runway would paralyze operations if visibility dropped.

The ILS on the secondary runway can be used by aircraft approaching from the Madhyamgram-end to the north of the airport. While flights are allowed to operate without ILS till there is clear visibility up to 2,000 metre, the visibility requirement is reduced to 800 metre if the landing strip has CAT-I ILS.

Sources said the delay had been caused by the mismatch between the report from the calibration aircraft and that of the ATC landing chart that led to a perceived error in the glide path of aircraft approaching the airport. The calibration was done three times, the latest on August 30, 2012.

The ILS comprises a localizer that provides information on horizontal deviation from the runway and glide-path that gives data on vertical deviation of the aircraft from the glide angle for landing.

It electronically guides planes to enable a perfect touchdown. This reduces human error as the pilot does not have to depend on visual landing alone.

The project, conceived over six years ago and scheduled to be completed by 2008, encountered a spate of delays following extension of the runway from 2,800 to 3,200 metre. On a couple of occasions, landings and takeoffs had to be suspended at night because the primary runway was under maintenance and the secondary runway was not equipped to handle night operations.

"Both runways now have ILS facility that will make operations at the airport more reliable and less prone to disruption due to emergency repair work on primary runway or bad weather. Also, if evening and night traffic increases manifold, the two runways can be pressed into operation," an airport official said.

However, the presence of a 120-year-old mosque 100 feet north of the runway continues to be an obstacle. Another design flaw which Kolkata airport suffers is the proximity between the two parallel runways. The distance between the two is less than what is required for parallel operations. If that were possible, it would have doubled the aircraft movements and reduced congestion during peak hours.

Source:    http://timesofindia.indiatimes.com