RMIT飞行训练课件－ADF Operations ADF操作二

航空发表于 2010-8-9 09:37:10

**** Hidden Message *****

航空发表于 2010-8-9 09:37:30

ADF Operations Aim • To learn the principles and considerations behind the operation of the ADF navigation system. Application • Supplementary navigation information • Orientation information (where am I?) • NVFR rating • IFR rating Overview • Definitions • Principles • Considerations • Air Exercise • Airmanship Definitions • NDB – Non-Directional Beacon, is the ground radio transmitter that radiates energy in all directions. • ADF – Automatic Direction Finder, is the airborne receiver which when tuned, indicates the direction TO the NDB. • Locator – Low powered NDB used for approaches in conjunction with an ILS. Principles • NDB Ground Stations Principles • NDB – Operates on frequencies between 200Hz and 500 KHz (LF to MF radio range). – Primarily short distance navigation aids of usually < 200Nm. – Transmitter power is between 100 and 3000W with majority in the 100 to 500W range. – Greater the transmitter power, the greater the range. – Details found in ERSA and ERC charts; VTC, TAC and VNC. Extract from ERSA (POINT COOK) FAC P – 292 Not for operational use Principles – The emitted wave has a Morse code identifier superimposed upon it, of 2 to 3 letters. – The carrier wave may also contain voice/ ATIS information. Extract from ERSA (POINT COOK) FAC P – 292 Not for operational use Extract from TAC-2 Not for operational use Principles • ADF – Airborne equipment consists of three main components: 1. Antennae 2. Receiver 3. Cockpit display Principles • ADF – Airborne equipment consists of three main components: 1. Antennae • loop antenna aligns itself perpendicular to the direction of the received signal. As it is a loop, two nulls are received - one removed 180 from the other. • To resolve the ambiguity the signal from the sense antenna is combined, to drive the loop (and hence the pointer) in the correct direction. Principles 2. Receiver – The receiver and associated control panel are used to tune the ADF to the required NDB. Principles General ADF modes: • OFF = Switch ADF off • ADF = Normal position for bearing information • ANT = Only sense antenna is used. No bearing information but enhanced audio reception • BFO = Beat frequency oscillator, rarely used in Australia • TEST = deflects needle to right wing. Pressing ADF again points needle to NDB Principles 3. Cockpit Display – The needle always points directly TO the station 038º M Principles 038º M HDG + RB = TO Station 038 + 226 = 264 Principles • Fixed Card ADF – The needle indicates relative bearing of the station from the aircraft Principles • Rotatable-Card ADF – The needle indicates a magnetic bearing TO the station. Any change in HDG requires realignment of the ADF card. Principles • Radio Magnetic Indicator (RMI) – Is a gyro-stabilised ADF which automatically aligns the card, and indicates magnetic bearings. Considerations • The ADF/NDB system has various limitations and errors that must be considered. These are: N – Night C – Coastal T – Terrain T – Thunderstorm T – Tuning / Co-channel H – Height M – Mountain Q – Quadrantal Considerations • Night effect – Radio waves take two paths; ground waves (along the Earth’s surface) and sky waves. – During the day the sky waves are absorbed by the lower ionosphere. At night the ionosphere reflects the sky wave back, mixing with the ground wave, causing errors. Considerations Extract from ERSA (Darwin INTL) FAC D – 114 Not for operational use Considerations • Coastal refraction – When passing from land to sea at an oblique angle, NDB radio waves may be refracted (bent) due to different conducting and reflecting properties of land and water. Always refracts towards the land (away from the normal). Considerations • Terrain effect – Radio signals have greater range over water than over sandy or mountainous country where the range is considerably reduced. Considerations • Terrain Effect Extract from ERSA (Darwin INTL) FAC D – 114 Not for operational use Considerations • Thunderstorm – Thunderstorms generate a lot of radio energy, and the ADF needle may point towards it; a poor mans weather radar. Considerations • Incorrect tuning – The receiver must be correctly tuned. Incorrect tuning will cause false bearing indications, restricted range, reversed sensing indication and possible co-channel interference from adjoining frequencies. Considerations • Co-channel interference – signals received from other NDBs operating on the same frequency, may give false bearing information. (eg: SHT and BNS) Generally NDBs of similar frequencies are spaced well apart geographically. Extract from ERSA FAC S – 324, FAC B – 30, Not for operational use Considerations • Height – The range of an NDB over the sea is relatively independent of aircraft height. – However, over land, and particularly over unfavourable terrain, range can be improved considerably as the aircraft climbs higher. Extract from ERSA (Darwin INTL) FAC D – 114 Not for operational use Considerations • Mountain effect – fluctuating bearings may result from the mixing of radio waves reflected from the surfaces of mountains. – higher frequencies minimise this effect. Extract from ERSA (LATROBE VALLEY) FAC L – 197 Not for operational use Consideration Extract from ERSA (WONTHAGGI) FAC W – 400 Not for operational use Considerations • Quadrantal – Results from the metal construction of the aircraft. – The Needle of the ADF will align itself to the cardinal points of aircraft. (ie: N, E, S, W) when station in between these quadrants. Air Exercise T I T - Tune to NDB using receiver - Identify using Morse code - Test by depressing TEST switch Airmanship • Always use NDB within it’s rated coverage • TIT checks before use • AM stations not to be used for navigation • Instrument taxi checks to be completed • Always refer to the ERSA for specific aid information and Limitations

猪也能飞 发表于 2013-10-28 19:28:44

感谢楼主万分感谢感谢万分

xy8701 发表于 2015-4-7 22:36:56

谢谢楼主，我正准备去RMIT读书

页: [1]

航空论坛_航空翻译_民航英语翻译_飞行翻译's Archiver

RMIT飞行训练课件－ADF Operations ADF操作 二

RMIT飞行训练课件－ADF Operations ADF操作二