Navigation Using a VOR

a vor is a radio station that transmits radio navigation signals in the very high frequency or VHF band the station transmits radio signals called radials in every direction away from the station pilots use 360 radials one for each degree in a circle to determine position if the equipment in the airplane says the airplane is on the three six zero Degree radial then the airplane is north of the vor an airplane on the 90 radial is east while one on the one eight zero Degree radial is due south of the station since pilots rely on the compass for directional guidance the radials transmitted by vor s are aligned with magnetic north before using a vor for navigation it must be tuned and identified tuning in the vor is a simple matter of selecting the proper frequency on the receiver next configure the airplanes audio system so that you can monitor the audible Morse code identifier which is broadcast by the vor station each vor has a unique three-letter identifier by hearing the Morse code for this three-letter identifier you've positively identified that the signal on your display is being received from the intended vor to find your location from a vor turn the Omni bearing selector knob or OBS knob on the vor receiver display until the needle centers and the - from flag indicates from once the needle is centered your magnetic bearing or radial from the vor is shown on the top of the display for example if the reading was 135 this tells you the airplane is located over the 135 radial in other words the airplane is southeast of the vor one thing that can be very confusing when learning vor navigation is that the radial you are on has nothing to do with your heading you could be on a 135 radial and headed north south or any direction to find the direction to a vor rotate the OBS until the needle is centered with a to indication the number shown on the top of the display is the bearing from your airplane to the vor this is exactly the opposite of the direction from the station to the airplane therefore your bearing or radial from the station is also shown on the bottom of the display to fly directly to over you are with the needle centered with a two indication turn the aircraft to the bearing on the top of the vor receiver display since the vor is displaying the direction to the station and your airplane is flying the heading you will be heading directly to the vor however the airplane will drift with the wind unless a crosswind correction is applied to correct for the win maintain your heading and observe the movement of the needle which is referred to as the course deviation indicator or CDI if the needle moves right or left it indicates the need to move the airplane right or left to stay on course to the station this is another confusing concept of vor navigation the needle is not telling you to turn right or left it's telling you to move the entire airplane right or left of course in order to do this you will have to turn the airplane however your goal is to adjust the heading with the purpose of moving the airplane laterally remember the needle is giving you position information which has nothing to do with your airplanes heading for example if you were directly south of a viewer on its 1/8 zero Degree radial then centering the needle with a two indication would result in three six zero being shown since the vor is directly north of the airplane turning the airplane to a 360 heading will get us heading towards the station while maintaining a three six zero degree heading observe the movement of the CDI let's say the CDI begins to move to the right in this case the instrument is telling us that we are drifting to the left with the wind when we maintain a360 heading at this point we must choose a new heading to counteract the airplane drifting to the left will turn right and establish the airplane on a zero one five heading maintaining this new heading observe the movement of the CDI let's say it continues to move right we can gather that a 15 degree heading is not enough to counteract the wind a greater correction is required so let's turn further right to a heading of zero three zero while maintaining a zero three zero degree heading the needle begins to move back towards the center of the display this means a zero three zero heading more than counteracts the wind and we are returning to our desired course maintain our new heading until the CDI is centered once the needle is centered we make a guess as to what heading will perfectly counteract the wind we know from our experience so far that a zero three zero heading more than counteracts the wind but a fifteen heading fails to counteract the win so we should pick a heading between these two we decide to try a zero two zero heading after maintaining that zero two zero heading for a few minutes the CDI needle is still centered this process of determining the proper heading for wind correction is known as bracketing since you progressively narrow the range of headings the desired wind correction heading lies within to fly directly away from a vor with the needle centered with a from indication turn the airplane to the bearing shown at the top of the vor receiver display this will result in the airplane flying directly away from the station this is because you have turned the airplane to a heading that is the same as the direction your airplane is from the station track the radial away from the station using the same bracketing technique as when flying to the station if you attempt to track a radial from the station with a two flag being displayed the needle will work in Reverse the pilot would need to fly away from the needle not towards it in order to keep it centered this is also true if flying to the station with a from flag to alleviate this reverse sensing make sure that - from flag displays the correct indication if it does not rotate the OBS until the desired flag appears the - from flag may also display an off indication the authentication is shown when neither a - from indication is appropriate for the OBS selection such as a selection that would take the airplane neither - or from the station it is also displayed when directly over or very close to the navigational aid if none of these conditions exist then an off flag could indicate a loss of signal from the nav aid since the radials a vor transmits all originated at the vor station itself the distance between radials increases the further the airplane is from the station this means that the needle is slower to respond at greater distances from the vor since the airplane must move a greater distance to move from one radial to the next as the airplane gets closer and closer to the station the needle will become more and more sensitive making it more and more difficult to keep centered when over flying a vor the needle will become more and more sensitive until when very close to the navigate the needle will likely swing all the way to the left or right at these close distances simply remain on your heading the - from flag will change to an authentication as you pass the station once on the other side the from flag will appear as you track outbound from the station the needle will become less and less sensitive with your increasing distance from the vor oftentimes it is desirable to track a specific radial to do so dial the radial you desire to track using the OBS turn the airplane to a heading that is the same as the course you selected with the OBS the airplane is now roughly paralleling your desired core next select a new heading which will intercept the desired course if the needle is not deflected to full-scale only a small heading change may be required such as 15 or 30 degrees in the direction of the needle deflection if the needle is deflected full-scale a greater intercept heading may be required you may choose to use the OBS knob to Center the needle with a from indication to see which radio you're currently on then return the OBS to the desired course choose an intercept heading in the direction of the needle between 30 and 90 degrees left or right of your current heading when the needle begins to Center turn to the desired course track the desired radial using the bracketing technique to correct for wind drift DME or distance measuring equipment consists of stations on the ground and equipment in the airplane DME operates in the ultra-high frequency or UHF band of frequencies when a vor is fitted with DME equipment it is referred to as a vor/dme each VHF vor frequency is paired with a specific UHF DME frequency this means the pilot only needs to use the vor frequency and does not need to be concerned with the DME UHF frequency before using DME identify the DME to be used by listening for its Morse code identifier DME equipment does not have its own unique identifier instead it uses the identifier of the vor to which it is attached the DME will transmit its parent vor s Morse code identifier once every 30 seconds DME operates by measuring the time it takes for a radio signal to be relayed from the airplane to the ground-based DME equipment and back the result is displayed in nautical miles to the pilot 8 a can is a ground-based navigational aid used for tactical air navigation by military aircraft it's operation is not very similar to a vor DME and the azimuth transmitted from attack end can only be received by military aircraft civilian aircraft however can receive the DME portion of a TAC end it's common for a TAC and transmitter to be fitted with equipment which allows it to be used as a vor or attack in these joint civil-military navigational aids are called vortex from the civilian user perspective a Vortech is identical in use and function to a vor/dme a vor test facility broadcasts test signals to permit pilots to check the accuracy of their aircraft's a vor receiver VOT locations and frequencies are listed in the airport facilities directory to use a vo t simply tune its frequency the vo T does not broadcast a signal usable for navigation instead it broadcasts a test signal which tells your aircraft it is directly north of the vo T station regardless of its actual position this means your onboard vor will always indicate zero degrees from or 1/8 zero degrees to when the CDI is centered you

Channel: Humble Aviation

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Keywords: written, test, Single, engine, piston, land, rising, wings, wing, general, aviation, online, ground, school, private, pilot, how, airplane, operation, works, tutorial, vor, navaid, navigation, radio, omni, range, VHF, tracking, radial, bracketing, to, from

Id: iCCk2ch-xL4

Length: 12min 29sec (749 seconds)

Published: Fri Mar 11 2011