This article has been divided into the following 8 parts:

  1. Definitions
  2. The Background
  3. Flight Information Regions (FIRs)
  4. Airspace Classification is as follows
  5. Technologies (AIDs) to Facilitate Air traffic movement and Airspace Management
  6. Airspace Charges
  7. Barriers to bring the change
  8. Conclusion

1. Definitions:

Airspace: A 3-D volume of the earth’s atmosphere in which aircraft and aerial objects fly.

Air Traffic Management: All system that assist aircraft to depart from an aerodrome, transit into airspace and land at a destination aerodrome which includes:

  • ATS (Air Traffic Services)
  • ASM (Airspace Management)
  • ATFCM (Air Traffic Flow and Capacity Management)

2. The Background

  1. In the year 1909, the first attempt to regulate the air space happened.
  2. In the year 1919, (Paris Convention), the right to individual countries to claim the sovereignty over their aerial airspace was formally formed.
  3. In the year 1944, (Chicago Convention), provided the first definitive delimitation of the physical boundaries of national airspace.
  4. In the year 1982, (UN Convention) the above laws were strengthened and named as UNCLOS (UN Convention on the Laws of Seas).
  5. All states were broadly separated by these criterion 22 km laterally and 100 km vertically (KARMAN line)

NOTE: Beyond the above two limits( 22 km laterally and 100 km vertically (KARMAN line)) the airspace available is international airspace.

3. Flight Information Regions (FIRs)

  1. All Sovereign airspace that is used by commercial air traffic is divided into number of FIRs (Flight Information Regions).
  2. ICAO (International Civil Aviation Organisation) has divided airspace into 7 categories from A – G. A being most controlled and G being least controlled. (F & G airspace are uncontrolled).
  3. Airspace A to E are known as controlled airspaces, F airspace known as advisory airspace and G airspace known as Flight information service airspace.
  4. Each FIRs may have many controlled areas and controlled zones.
  5. FIRs are extended vertically upward from the ground to a predetermined upper limit or Flight Level (FL). 
  6. The airspace above FIRs is called Upper Airspace or UIRs (Upper Flight Information Region).

NOTE: VFR (Visual Flight Rules) and IFR (Instrument Flight Rules)

VFR: These are set instruction or regulations under which a pilot operates an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. Flights under these conditions are called VFR flights.

IFR: Rules which allow a properly equipped aircraft with all instruments to be flown under Instrument Metrological Conditions (IMC).

4. Airspace Classification is as follows

Class A. IFR flights only are permitted, all flights are provided with air traffic control service and are separated from each other. 

Class B. IFR and VFR flights are permitted, all flights are provided with air traffic control service and are separated from each other. 

Class C. IFR and VFR flights are permitted, all flights are provided with air traffic control service and IFR flights are separated from other IFR flights and from VFR flights. VFR flights are separated from IFR flights and receive traffic information in respect of other VFR flights.

Class D. IFR and VFR flights are permitted and all flights are provided with air traffic control service, IFR flights are separated from other IFR flights and receive traffic information in respect of VFR flights, VFR flights receive traffic information in respect of all other flights. 

Class E. IFR and VFR flights are permitted, IFR flights are provided with air traffic control service and are separated from other IFR flights. All flights receive traffic information as far as is practical. Class E shall not be used for control zones. 

Class F. IFR and VFR flights are permitted, all participating IFR flights receive an air traffic advisory service and all flights receive flight information service, if requested.

Class G. IFR and VFR flights are permitted and receive flight information service, if requested.

5. Technologies (AIDs) to Facilitate Air traffic movement and Airspace Management

Generally, all aviation related communication happens on Radio Frequencies which are based on Electromagnetic Waves.

The band of frequency used is as follows:

5.1 Radio Navigation Equipments

  1. NDB (Non-Directional Beacon) – Ground based radio stations, which provide a facility of obtaining bearings on them from an aircraft, are known as Non-directional beacons. Work in the frequency range of 200 to 400 KHz in the low (30 to 300 KHz) or medium (300 to 3000 KHz) frequency band in all directions from the point of transmission. Non-directional beacon (NDB) is a radio transmitter which provides guidance to aircraft in all directions equally, without any directivity aspect in its radiation. It is a low or medium frequency navigational aid.
  2. VOR (Very High Frequency Omni Directional Radio Range): It is the basic electronic navigation that is in use today. This navigation method relies on the ground-based transmitters which transmit signals to VOR receivers onboard the aircraft. The VOR system operates in the VHF band (30 t0 300 MHz), from 108.0 to 117.95 MHz. The reception of VHF signals is a line-of-sight situation. So, for locating a VOR, the aircraft has to be at line of sight with the ground transmitter. VOR provides aircraft radial with respect to a ground station.
  3. DME (Distance Measuring Equipment): DME, as the name indicates is an electronic equipment used to measure slant range distance between aircraft and a ground station. The DME operates in the UHF range (300 to 3000 MHz). It is used either as a navigation aid in conjunction with very high frequency Omni direction radio range (VOR), or as a component of the Instrument landing system (ILS). Because the distance measurement taken by the aircraft DME receiver is from Air-to-Ground, DME records slant ranges which are greater than the actual distance between the ground facility and the ground position of the aircraft.
  4. ILS (Instrument Landing System): Its function is to provide the PILOT or AUTOPILOT of a landing aircraft with the guidance to and in some cases, along the surface of the runway. This guidance must be of very high integrity to ensure that each landing has a very high probability of success. This facility is useful to a landing aircraft in all weather conditions but it plays very vital role under poor visibility and low cloud ceiling conditions.
  5. Glide Path: The glide path transmits a radio signal which establishes a glide angle along the approach course defined by localizer. Vertical deflection of the needle in the CDI tells pilot that he/she is above or below the glide angle. Frequency range of operation of glide path is in UHF band from 328 MHz to 336 MHz.
  6. RADAR: It is basically a means of gathering information about distant objects called ‘targets’ by sending electromagnetic waves at them and analyzing the returns called the ‘echoes. It was evolved during the second world war independently and more or less simultaneously by USA, Great Britain, Germany and the France. The word RADAR is an acronym coined by the US Navy from the words Radio Detection and Ranging. Radar is a radio device capable of providing information on range and bearing, in azimuth and/or elevation of objects. Most of the modern pulse Radar systems use measured bursts of radio energy called “pulses”, which after transmission are reflected by the objects, e.g., aircraft, moisture laden clouds, rain drops, etc. As this reflected energy is of very low power, it is suitably amplified and then displayed on a Cathode Ray Tube (CRT) or Liquid Crystal Display (LCD) monitor for visual presentation.   

RADAR are further classified as:   

  • Primary
  • Secondary

Types of Radar

  1. Aerodrome Surface Control Radar: Also called as Airport Surface Movement Indicator (ASMI) and Airport Surface Detection Equipment (ASDE) or Surface Movement Radar (SMR). Here the radar scans the airfield only and draws a realistic map of the airfield on the scope on which moving and stationary targets are identified. It is an aid for maintaining separation between the aircraft taxiing, taking off and landing, when the controller may not be able to actually see an aircraft maneuvering on the ground due to poor visibility. The picture is so precise that even a man walking on the runway can be seen on the scope.
  2. Airport Surveillance Radar (ASR): It is also called Terminal Approach Radar. It is a short-range radar with a maximum range of about 60 nautical miles. This radar continuously scans the airspace surrounding the radar site and is used for terminal control, i.e., for guiding the aircraft from the initial approach to a point on the extended centerline of the runway from where final approach starts. In conjunction with the PAR, it forms the Ground Controlled Approach System (GCA). No building, structure or object is permitted to be erected within 305 m radius of the antenna and above an angle of elevation of 0.5 degree beyond this.
  3. Precision Approach Radar (PAR): Being an important constituent of the Ground Control Approach system, this radar is used to guide a landing aircraft for a safe landing. It is designed to accurately determine the range from the touchdown point, bearing with reference to the extended centerline of the runway and the elevation with reference to the glide angle of an aircraft on the final approach to land. This radar can also be used to cross-check the performance of the instrument landing system.
  4. Air Route Surveillance Radar (ARSR): This is a long range radar with a maximum range of about 200 nautical miles. The main purpose of this radar is to monitor the air traffic in an area control center. No building, structure or object is permitted to be erected within 610 m radius of the antenna and above an angle of elevation of 0.5 degree beyond this. 
  5. Secondary Surveillance Radar (SSR): This is a secondary radar. The aircraft carries a transponder which replies to suitably coded interrogations from a ground station. From the transponder replies, it is possible to extract information regarding the aircraft like its call-sign, altitude, originating point, destination point etc.  

NOTE: All these equipment are very costly and even the regular maintenance is not easy. Aerodrome operator who is providing all these facilities have to keep these facilities always in a condition so that it provides accurate data and reliable services for the aerodrome operator chargers fees who so ever (generally airlines) is using these facilities.

6. Airspace Charges

Three different charges are levied for using the airspace around the aerodrome:

  1. En-route charges (controlled and administered by registered States)
  2. Terminal Navigation Fees (collected and administered locally by airport operators)
  3. Communication Fees (collected and administered locally by airport operators)

NOTE: Some longer route may provide significant cost cutting in the charges helping to bring down the flight expense.

7. Barriers to bring the change

  • Technology costing too much
  • Political pressure
  • Social and Economic factors
  • Safety Parameter of different countries
  • Existing airport and runway structural parameters

8. Conclusion

Still there are airports which are not equipped with the above technological facilities due to many reasons and at some airports there are scope for some upcoming latest technologies such:

  • Continuous Climbing Operations (COOs)
  • Continuous Descent Operations (DDOs)

All these help in providing flight level soon and more accurately.

THE END

Go Where You Feel The Most Alive!

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