To reach the destination, to find the exact lo-cation, to navigate accurately; to be equipped with electronic computers, to aid in navigation, several different kinds of aeronautical charts, to show the location of various landmarks, to broadcast air navigation signals, every enroute high altitude airway, the portrayal of the airway jet routes, identification and frequency of radio aids, selected airports, time zones, pilotage, dead reckoning, radio navigation, to keep on course by following landmarks on the ground, in all weather conditions, few or no visible landmarks, to follow the preplanned route of flight, to prevent the plane from keeping ex-actly on course, to tune the radio navigation equipment, to receive a signal from a ground -
stationed NAVAID, to fly on a direct course to or from the station, to drift off course, the major aid in air navigation, the low-frequency radio re-ceiver, to home on signals from the radio station, a line connecting one navigational aid to another, airway corridors, to be identified on the pilots’ aeronautical chart, to designate the route of flight via the airway system on the international flight plan, to tune and identify the NAVAID, to pro-ceed inbound to the NAVAID, the radial which defines the airway as shown on the aeronautical chart, to proceed outbound, on another airway radial, to reach a changeover point, to switch from tracking outbound on the original NAVAID to inbound on another new one, other methods for navigating across oceans.
B: Read Text “Air Navigation” and pay attention to the way they are used in the context.
Text AIR NAVIGATION
During the climb, the emphasis in the cock-pit quickly shifts from manipulating the con-trols to an air navigation. Air navigation is the means by which pilots reach their destinations and find their exact locations at any time. All airlines have compasses and other instruments to help pilots navigate accurately; some are also equipped with electronic computers to aid in navigation. However, the most essential aid to air navigation is the aeronautical chart.
There are several different kinds of aero-nautical charts. Some look much alike maps: they show the location of various landmarks, airline routes, landing fields, and radio stations that broadcast air navigation signals. Another chart which is widely used shows aeronautical information for every enroute high altitude airway in a given region.
Information on this kind of chart (some-times called a radio chart) includes the portrayal of the airway jet routes, identification and fre-quency of radio aids, selected airports, distance, time zones, and related information – all of which is needed for radio navigation.
The three chief methods of air navigation over land are pilotage, dead reckoning, and radio navigation. Most pilots use a combination of all three of these methods.
Pilotage is the simplest and most common me-thod of air navigation. Using this method, a pilot keeps on course by following landmarks on the ground. For a commercial pilot this system is not very practical since it cannot be used at high alti-tudes and in all weather conditions. The second method of air navigation, dead reckoning, is a way of navigating when there are few or no visible landmarks. Dead reckoning takes more skill
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and experience than pilotage. Here the pilot uses an aeronautical chart, a clock, compass, and small computer (a slide rule) to follow the preplanned route of flight. Dead reckoning is not always successful because changing winds prevent the plane from keeping exactly on course.
Radio navigation is used by all commercial pilots, as well as by most other pilots. For this type of navigation, the pilot tunes the radio navigation equipment so as to receive a signal from a ground – stationed NAVAID (naviga-tional aid). A needle on the equipment tells the pilot when he is flying on a direct course to or from the station. It also shows when the aircraft drifts off course so that its direction can be corrected.
The most common system designed for civil aircraft is called VOR (very-high-frequency omnidirectional radio). Airlines also use another special device called DME (dis-tance measuring equipment). This combined system is known as VOR / DME. A similar system used almost exclusively for military air-craft is called TACAN (tactical air navigation). A combined system, called VORTAC, can be used by both civil and military aircraft. Before evolution of these systems the radio compass low-frequency radio receiver together with the nondirectional beacon (NDB) was the major aid in air navigation.
The low-frequency radio receiver allows the pilot to home on signals from the radio station.
Airways are formed by a line connecting one navigational aid to another. These airway corri-dors are identified on the pilots’ aeronautical chart. When the pilot plans a mission, he desig-nates the route of flight via the airway system on the international flight plan, which is then filed with ATC. In flying on an airway, the pilot tunes and identifies the NAVAID to be used, then proceeds inbound to that NAVAID on the radial which defines the airway as shown on the aero-nautical chart. After passing over the station, he proceeds outbound on another airway radial. Soon the aircraft reaches a changeover point. At this point the pilot switches from tracking out-bound on the original NAVAID to inbound on another new one.
This process is repeated from NAVAID to NAVAID until the pilot reaches the destination. Pi-lots, however, use other methods for navigating across oceans.
There are three transoceanic navigation sys-tems commonly used by civilian air transports throughout the world:
1. Inertial navigation system. 2. LORAN.
3. Decca.
Ex. 133. For detailed information read the text again and answer the questions:
1. What are the three chief methods of air navigation?
2. What is pilotage? Why isn’t it used by commercial airlines? 3. How does dead reckoning differ from pilotage?
4. What is radio navigation?
5. Most pilots consider DME distance as what kind of distance? 6. What NAVAIDS compose a VORTAC?
7. How are airways formed?
8. What is the difference between “inbound” and “outbound’’? 9. Explain the process a pilot follows in order to fly on an airway. 10. Name the three principal transoceanic navigation systems.
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Vocabulary Practice
Ex. 134. A: Complete the following sentences with the suitable word or phrase. Refer to Text “Air Navigation”
1. An……………………………………will depict the airway structure for a ………………………………………………………………………… given region.
2. …………………….. is the simplest form of navigation.
3. All commercial pilots use ……………………….. navigation.
4. With the instruments in the cockpit, a pilot can tell if he is ………………………… ……………………………going to or from ……………………………………………..
5. The most common radio navigation aids today are the……………….
6. A pilot can …………….. on a signal received from a nondirectional beacon. 7. Distance measuring equipment measures......
8. In flying on an airway, a pilot must fly.... and.... each NAVAID used. 9. LORAN means ……………………………..
10. Radio navigation is the means by which pilots can reach their ……………………….and find their exact …………………… at any time.