NAL instrument to facilitate safety of civilian aircraft

An indigenous instrument that will guide pilots of commercial aircraft on runway visibility in dense fog conditions is likely to be installed at 70 airports across the country, saving crores of rupees in foreign exchange.

Developed by researchers at National Aerospace Laboratories, Bangalore, the “Drishti” system challenges the monopoly of a handful of foreign companies that charge exorbitantly to install similar systems in Indian airports.

Seven of these indigenous systems are working at Delhi, Kolkata and Lucknow international airports for the last three years. Delhi airport has five of these instruments that worked well in severe fog conditions.

“Our system costs one-third of the price of imported instruments,” V Shubha, chief scientist at the material science division of NAL, who spearheaded the project, told Deccan Herald.

NAL on Thursday signed an agreement with Indian Meteorological Department to install 70 such systems at Indian airports within the next three years. While NAL will produce the “Drishti” instruments, IMD's responsibility includes procuring and certifying the systems and arranging the communication links. Each indigenous system would cost approximately Rs 25 lakh.

Called “transmissometer”, the instrument will automatically check the runway visibility every 10 seconds and feed the information to the Air Traffic Control, which in turn will inform the pilots. It is suitable for all categories of airports with CAT I, II, III A and B instrument landing system.

Even though having this instrument is mandatory for all airports as per the International Civil Aviation Organisation and World Meteorological Organisation norms, there is no Indian system currently available in the market. Imported instruments from Finland and Australia cost much higher.

The NAL system operates within a broad range varying from the lowest (less than 25 mt) to the highest visibility (more than 2000 meters) aiding pilots for safe landing and take-off. In December 2011, the system worked perfectly for 10 consecutive days at Delhi airport, engulfed by a thick cover of fog.

“Drishti” uses a high-technology lamp and a photo-detector in its core. In case of fog, the light transmitted to the detector is cut off and the intensity of the light goes down. “From that information, it can calculate the runaway visibility range,” Shubha said.

“By this winter, the Airport Authority of India wants to make five more airport around Delhi CAT-IIIB compliant. They include Lucknow, Jaipur and Ahmedabad. All of them will have this instrument. For CAT-III landing system, each runway should have three Drishti systems, which we will produce,” NAL Director Shyam Chetty told Deccan Herald.