航空 发表于 2010-8-9 09:37:10

RMIT飞行训练课件-ADF Operations ADF操作 二

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航空 发表于 2010-8-9 09:37:30

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