Flight Inspection Unit Flying it safe
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The calibrations are required to be done on a regular basis, so that the equipment may be certified for use. Considering the vast geographical reach of the country and the range of installed CNS equipment to be tested, the FIU is an important service to ensure flight safety. The need for expanded FIU operations is critical given the increase in the number of airports and the expansion of existing facilities, e.g, extended or new runways.
The services provided by Flight Inspection Unit (FIU) ensure the integrity of instrument approaches and airway procedures that constitute our national airspace infrastructure and the Airports Authority of India’s (AAI) international commitments as Air Navigation Service Provider (ANSP). This is accomplished through the airborne inspection of all space and ground-based instrument flight procedures and the validation of electronic signals in space transmitted from ground navigation systems.
Airborne inspection of navigational aids is a two-part operation, requiring the skills of highly trained flight crews. The first part is an evaluation of the “signal in space” - the radiation pattern of the navigational aid. The second part is to certify the instrument approach procedures that are designed to allow pilots to safely use airport runways in adverse weather.
Every contracting state to the International Civil Aviation Organization (ICAO) is required in terms of the Convention on International Civil Aviation, commonly known as the Chicago Convention, and its Annexes, to ensure the safety of navigational aids at airports. Consequently, each contracting state is obliged to provide in its territory airports, radio services, meteorological services and other air navigation facilities to facilitate international air navigation, in accordance with the standards and recommended practices (SARPS) established from time to time pursuant to the Convention.
In general, monitoring equipment design is based on the principle of continuously monitoring the radiate signals-in-space at specific points within the coverage volume to ensure their compliance with the specified standards. Although, such monitoring provides to some extent, an indication that the signal-in-space at all other points in the coverage volume is similarly within tolerance, this is largely inferred. It is therefore essential to carry out rigorous inspections at periodic intervals to ensure the integrity of the signal-in-space throughout the coverage volume.
Flight Inspection function is carried out by the Flight Inspection Unit (FIU) ofthe Airports Authority of India, located at Safdarjung Airport, New Delhi. It ensures that navigational aids in India are safe, by focusing on two distinct areas: It carries out precision certification for the commissioning of newly installed air navigation systems. It periodically checks the technical and operational parameters of existing surveillance and navigational aid instruments.
HISTORY AND DEVELOPMENT
Flight inspection has long been a vital part of providing a safer air transportation
system. Flight inspection began functioning with the development of an airway system in the early 1920s. The concept is almost as old as the airways themselves. The first flight inspectors flew war surplus open-cockpit biplanes, bouncing around with airmail pilots and watching over a steadily growing airway system predicated on airway light beacons to provide navigational guidance. The advent of radio navigation brought an increased importance to the flight inspector, as this was the only platform in the air that could evaluate the radio transmitters from where they were used.
With the development of the Instrument Landing System (ILS1) and the Very High Frequency Omni-directional Range (VOR2), flight inspection became an essential element to verify the accuracy of the system. Flight inspection has been there all along, quiet and meticulous, changing and developing through various government agencies charged with air safety. With continued growth of air transportation, and new technologies to support that growth, the essential means of flight inspection also changed, but its foundation, that of ensuring aviation safety, still remains the same.
The requirement of Flight Inspection of Navigational Aids (Nav-aids) in India was felt by the Director General of Civil Aviation (DGCA), the Indian Civil Aviation Authority in the year 1959. Customized aircraft were used for flight inspection, with dedicated receivers and sensors to collect data from the navigational aids being inspected. India started with Flight Inspection activity from Allahabad in 1959 with Dakota aircraft fitted with necessary receivers, signal generators, deflection meters, Ink recorders, manual theodolites etc. The initial Nav-aids which were inspected include AD200 VHF Direction Finder and Lorenz VOR /Wilcox (Distance Measuring Equipment) DMES.
The system had lot of shortcomings like, clumsy ink recorder, totally manual positioning system, low repeatability and long Flight testing Hours. With technological advancement in the Electronics field, improved systems were available and DGCA immediately upgraded its system.
Later, the Flight Inspection Unit (FIU) base was shifted to Delhi and in the year 1981-82 the system was replaced by flight inspection system from M/s Sierra Research Corporation, USA installed in HS748 AVRO aircraft. This system was using UV (Ultraviolet) recorder and Radio Telemetry Theodolite (RTT). The system sufficed for the time being, but had its own shortcomings. Still the result had to be manually calculated and positioning accuracy dependent on manual tracking accuracy. Repeatability was still an issue and Archiving of Inspection records was cumbersome. To improve the system performance, the Flight Inspection system was replaced in the year 1988-89 by a new (Flight Inspection System) FIS from M/s Normarc.
This system was built with Single Board Computer cards, worked under a computerized data acquisition and processing environment. The systems were installed in newly acquired Dornier 228 aircrafts to reduce operational cost of flying HS -748. It was a semi-automatic system from M/s Normarc using Laser auto tracker, Bubble memory cassettes, dot matrix printer and a thermal printer as well. Flight Inspection results could be generated automatically with graphical printouts. It was provided with EHSI (Electronic Horizontal Situation Indicator) display for situational awareness. This system was a jump in technology for flight inspection from a manual environment to an automated computerized environment. It was having better repeatability, data archival in digital form, automated results, absence of error, lesser hours for flight Inspection, better situational awareness for the flight inspector during inspection, less workload for flight Inspector and resulting in ample time for scrutinizing the collected data during Flight Inspection.
The Normarc system was meeting most of AAI’S requirements but it was not certified for Cat III ILS Inspection and high altitude requirements for Leh Airport. The Bubble memory cassettes used in the system became obsolete. In 2004, the system was replaced by AFIS -Aerodata. 200 systems from M/s Aerodata.
AAI also got one such system installed in a newly acquired B -350 King Air aircraft to meet high altitude requirements. Fully Automatic Flight Inspection System-afis-200 system uses GPS
Dornier DO-228 Aircrafts with AFIS-200
DGPS and LT Ground position reference System