The objective of an aviation meteorological service is the safety, regularity and efficiency of international air navigation by the provision of timely and accurate weather information. An aircrew must be able to access accurate weather information when planning their flight, given the changing nature of the earth’s weather patterns. The information needs to be regularly updated to ensure safety for every planned flight. This is achieved by providing necessary meteorological information to aircraft operators, flight crew, air traffic services units and airport management through a network of international communication systems that underlines a close liaison between those supplying meteorological information and those using it.
In order to ensure the safety, economy, regularity and efficiency of global air navigation, national meteorological services throughout the world make meteorological observations and forecasts through sustained monitoring and warning systems in their respective countries, as per the standards and guidelines provided by the World Meteorological Organisation (WMO) and the International Civil Aviation Organisation (ICAO). India Meteorological Department (IMD), under the Ministry of Earth Sciences (MoES) is the national agency in India responsible in all matters related to aviation meteorological services that are provided for national and international flights for safe and efficient operations in terms of take off, landing and en-route forecasts. These services are provided through a network of meteorological watch offices (MWOs) in the four international airports at Chennai, Kolkata, Mumbai and New Delhi and 68 other aviation meteorological offices.
The aviation meteorological offices provide airport-specific current weather reports, forecasts and warnings for safety, economy and efficiency of aircraft operations. In view of this, there is a continuous need to upgrade and augment instrumentation through state-of-the-art observation systems and decision support systems in tune with the pace of modernisation of various airports throughout the country.
Aviation being a technology-intensive sector, meteorological services needs to be primarily driven by technology. The instrumentation requirements for Aeronautical services involve:
- Sensors capable of continuous recording of basic meteorological parameters like wind, temperature and pressure.
- Instruments for assessment of other parameters like visibility and run visual range.
- Integrated instrument system for detection of low level wind shear and microburst along the glide path and departure corridor.
- Radar facility for detection and early warning of thunderstorms.
- Elaborate communication facilities for processing, visualisation and dissemination of data and messages on real-time basis during various stages of flight.
Initiatives to Improve Aviation Services
Integrated technological upgradation during 2007-2008 involved the observation and reporting of meteorological facilities at airports. This necessitates an array of sensors to be placed at specific locations at airports to measure meteorological parameters. The first set of automated instruments called the Integrated Aviation Meteorological System (IAMS) were imported and installed at major international airports like Delhi, Mumbai, Hyderabad, Bangalore, Amritsar Guwahati and Chennai. During this phase, airports susceptible to fog were also equipped with dual base line transmissometers.
In 2013-14, two Heliport Automated Weather Observing System (AWOS) were installed at Juhu airport in Mumbai and Sanjhi Chhat in Vaishno Devi, Jammu. Meant primarily for helicopter operations, these fuly-automated systems record weather parameters and broadcasts the same at pre-assigned frequencies to overflying helicopters and aircraft. Voice synthesisers are used to convert text messages into audio messages for VHF broadcast. Around ten such systems are in the pipeline for different locations in the Himalayan region for helicopter operations in difficult and inhospitable terrain.
An online briefing system, a web based briefing and documentation platform meant for pilots and flight dispatch officers was also set up in 2006. This was a paradigm shift from what was prevalent under the conventional system wherein officers were required to visit the concerned aeronautical meteorological office to receive the mandatory briefing and weather updates, without which no flight is permitted to take off. Under the web based system, they could log in to the briefing system, enter requisite parameters such as the origin and destination airport, alternate airport, flight level at which the particular flight was to fly and generate all the necessary weather information, warning and charts required to operate the flight safely and efficiently. The online briefing system has since been upgraded into an advanced version in 2012-13, and this facility is now extensively being used and patronised by the aviation community. Apart from the civil aviation sector, this briefing system is also used in equal measure by the Indian Air Force, Indian Navy, Coast Guard, Border Security Force and other government agencies for flight operations.
In 2014, MoES-IMD and Council of Scientific and Industrial Research-National Aerospace Laboratories (CSIR-NAL) entered a long term partnership agreement for design, development, operation and maintenance of instruments required for aeronautical met purposes. Under the aegis of this path breaking agreement, around 25 runway visual range measuring instruments called Drishti-transmissometers have been installed and made operational at different airports. Drishti is a glittering example of the ‘make in India’ initiative of the present government. Drishti takes into account the runway visual range value, which is an integral part of the instrumental landing system (ILS) for its operations.
In yet another technological advancement attained in association with Airports Authority of India, a facility has been developed for reception of aircraft data from Indian airspace at the IMD. The upcoming Air Traffic Management System at Chatrapati Shivaji International (CSI) Airport, Mumbai is equipped with the facility to segregate and disseminate the aircraft based meteorological observation on-real time basis to the IMD system. Utilising the navigational facility called Automatic Dependent Surveillance (ADS), aircraft periodically transmit their location, altitude, course and other navigational data to the ground station. The data packet also contains meteorological parameters like wind speed, direction, air temperature and, if encountered, a report on turbulence and icing. Once fully implemented across the country, aircraft observation will become the single largest source of high altitude real time data and significantly help improve the forecasting and forewarning capabilities over the Indian region.
Another ambitious project is an integrated Decision Support System for Aviation. Under this project, real time observation and forecasts from different source like automatic weather stations (AWS) data, aircraft data, radar observations, satellite data, and NWP products are assimilated to generate high resolution products of different temporal and spatial scales. These tailor made products and warnings are meant for tactical and planning requirements of different users involved in ATS operations, flight planning and airport operations.
Recognising the importance of fog forecasting for the aviation sector, an observational campaign was launched by the MoES in 2015, to understand the physical features of fog and factors responsible for its genesis, intensity and generation at the Indira Gandhi International Airport (IGI), New Delhi.
The IMD, on its part, implemented the augmentation of aviation meteorological services in 2015. This involved upgradation of airport meteorological instruments (AMI) at runways of major airports by commissioning airport weather observing systems, transmissometers, aviation weather decision and support systems. For this, the services of meteorological centres at Delhi, Srinagar, Mumbai, Jaipur, Shimla, Dehradun, Lucknow, Kolkata, Chennai, Guwahati, Nagpur, Pune, Chandigarh were put to use.
Challenges and way forward
The major challenges in providing information to the aviation sector could be summed up thus:
- Information is not always on time, especially in severe weather conditions;
- Accurate information is generally not available in case of turbulence or zero visibility for smaller airports;
- Information on runway visibility range not always timely for small airports; and,
- Persistent problems related to internet and telephone connections during severe weather at small airports.
Global aviation is poised to make a quantum jump in terms of optimisation of airport operation, globally interoperable system and data, efficient flight path and optimum capacity, and flexible and efficient flight path. The road map for this has already been defined by ICAO in its Aviation System Block Upgrade (ASBU) from 2013 to 2028. ASBU provides both an opportunity and a challenge to the MoES to upgrade and sustain capabilities in the area of:
- Enhanced operational decisions through integrated meteorological information (planning and near-term service); and
- Increased reliance on automated relay of meteorological data to and from aircraft, including enhanced aircraft based meteorological data reporting capabilities.
The challenge lies in developing state-of-the- art aviation support systems with advanced meteorological instruments and forecasting tools for all domestic airports. Besides, aviation meteorology being a very specialised sub domain of meteorological science, there is a urgent requirement of adequate qualified manpower. The training, competency assessment and certification of such manpower is another major challenge, which the MoES is currently assiduously working towards.
The impetus given by the MoES to this sector during the past decade has resulted in significant improvements in the level of service, enhanced user satisfaction and confidence in aeronautical met services. Cumulatively, it has gone on to significantly contribute towards overall improvement in the safety and efficiency of India’s aviation sector.