|An aircraft takes off from Patna airport amid cloudy skies on Wednesday afternoon. Picture by Jai Prakash
Runway visibility data is crucial for flight landing and take-off. But the Patna airport still follows an archaic method of determining it
Visibility at Patna airport is assessed manually, through human eyes:
• Weathermen at the airport meteorological office use precisely measured maps of the entire airport vicinity, including the approach path, using GPS devices
• Based on the visibility of various objects along the approach path from the airport, meteorological office and mathematical calculations, the final visibility is issued
• Interval between two reports is 30 minutes
• If visibility changes drastically between two reports, landing can be a risky affair
The city airport is set to get a modern gadget — transmissometer — for determining the runway visual range, crucial for flight operations.
India Meteorological Department (IMD) has recently sent an application to Airports Authority of India (AAI) for installing a transmissometer near the runaway of the airport. It would provide real-time visibility range digitally, replacing the existing manual process of calculating it.
“We have recently written a letter to the AAI, Patna, for installing the transmissometer. We have been informed that the application has been forwarded to the regional headquarters of AAI in Calcutta. It would be sent to the national headquarters in New Delhi from there. The transmissometer would be installed at one of the two ends of the single runway here. Once the equipment is in place, we would be able to provide precise details of the visibility condition on real-time basis to ensure smooth air operations,” said Ashish Sen, director, IMD, Patna.
Authorities at Patna airport claimed that the onus of installing the transmissometer was on the Met department. “IMD alone looks after the installation of transmissometer. We only provide the nod for installing the equipment,” said Sono Marandi, director (in- charge), Jayaprakash Narayan International Airport, Patna.
Like any other aerodrome, the Patna airport meteorological office provides weather related-information, including visibility, to the air traffic controller (ATC). The ATC at the source airport conveys the information to ATCs at other locations and all airlines operating from the airport.
The visibility has been of prime concern at the city airport because of short runway but it still lacks any digital machinery for calculating it. Even now, the visibility for operation of aircraft at this critical airport is assessed through human eyes — an unsafe and time-consuming process.
“Majority of the accidents in the aviation sector are linked to weather. The present system of assessment of visibility at Patna airport is a completely conventional method and does not give accurate information required in the modern aviation industry. Moreover, it is quite challenging for the pilots as well because they have to manually calibrate with the ATC on the visibility. The operating crew has to check with ATC the status of visibility before landing, which is not a globally accepted safe practice,” said Atul Singh, the executive director of Delhi-based Centre for Aviation, Policy, Safety and Research.
According to modern practices and guidelines of International Civil Aviation Organisation (ICAO), various state-of-the-art equipment, including transmissometer and instrument landing system, are used to calculate the available visibility. The city airport has a category-1 ILS but it lacks a transmissometer. As a result, the meteorological office issues the visibility condition using human eyes and a detailed scientific map made using Global Positioning System.
Sophisticated equipment like transmissometer gives a complete picture of the prevailing weather conditions in the entire airport area. Aviation experts hailed the decision of the Met department to install hi-tech gadget at the city airport.
“ICAO in its meeting in 2008 had issued instructions to all member countries to adhere to the standard visibility assessment norms, which is largely based on equipment based calculation. Such devices give automated and accurate information about visibility conditions and thus ensure smooth air operations,” said Atul.