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Tvor is a ? [ Question security ]

Question 186-1 : Vor with a limited range used in the terminal area low power dvor in the frequency range 112 mhz – 118 mhz test vor transmitting such a signal that the reference and variable signal are always in phase high power vor in the frequency range 108 mhz – 112 mhz

Vor applications.vors are used for en route navigation usually to define airway centrelines the overall required accuracy of the displayed information is ± 5° when european airways were first plotted out a lower accuracy of ± 7 5° was assumed to keep an aircraft within the confines of an airway 10nm maximum distance between the beacons was calculated to be 80nm .vor can be classified as follow .a terminal vor tvor is a low power beacon used as part of an airfield approach tvors share the lower frequencies with ils . .a broadcast vor is usually a terminal aid with a voice broadcast giving out the airfield weather atis superimposed on the carrier wave .a test vor vot is a very low power beacon sited at airfields it puts out a constant phase difference of zero in all directions this allows aircraft to test the accuracy of their equipment on the ground the vor test function is selected with a course of 000° set the course deviation indicator should centre with from indicated the rmi should indicate 180° qdm the beacon ident for a test vor is a series of dots .pay attention do not confuse a tvor with a test vor .question 623419 . .max range at which you will receive a signal/indication will depend on trasmitter power altitude receiver sensitivity atmospheric conditions and various other intangible factors .the max theoretical range in nautical miles was always worked out thus . .r = 1 23 h1 + h2 .where .h1 = altitude/ height of the reciver in ft . .h2 = elevation of the ground facility in ft.111 nm = 1 23 ft + 169 ft . .111 nm = 1 23 ft + 13 ft . . ft + 13 = 111 ÷ 1 23 . . ft + 13 = 90 4 . . ft = 90 4 – 13 . . ft = 77 24 . . = 77 242 . . = 5967 = fl60 exemple 286 Vor with a limited range used in the terminal area.Vor with a limited range used in the terminal area.

On an rmi the front end of a vor pointer indicates the ?

Question 186-2 : Radial plus 180° magnetic bearing from the station radial relative bearing

Refer to figure .heading the direction in which the longitudinal axis of an aircraft is pointed usually expressed in degrees from north true magnetic compass or grid .track the projection on the earth’s surface of the path of an aircraft the direction of which path at any point is usually expressed in degrees from north true magnetic or grid .radial a magnetic bearing extending from a vor/vortac/tacan .bearing the horizontal direction to or from any point usually measured clockwise from true north magnetic north or some other reference point through 360 degrees .heading vs radial.the radial gives the relative position of an aircraft to e g a vor .there is no mathematical relation between the radial and the heading or track of an aircraft i e one cannot be derived from the other .remember the vor needle indicates where the aircraft is radially with respect to the staion the arrow head indicates the qdm for the vor bearing to the vor station while the ther end shows the qdr or vor radial on which the aircraft is positioned at that moment exemple 290 Radial plus 180°.Radial plus 180°.

Which statement about the interrogation by the dme interrogator is correct ?

Question 186-3 : The interrogation does not start before pulse pairs of the tuned dme station are received the interrogation starts directly after the correct dme frequency has been selected on the frequency selecting panel by the pilot the interrogation starts when the interrogator has been warmed up sufficiently whether pulse pairs are received or not the interrogation can only take place if the echo protection circuit has been locked

Tuning the dme interrogator in the aircraft starts the transmission of pulse pairs in search mode no information is received by the interrogator at this point when the pulse pairs are received by the transponder at the ground station it adjusts the frequency by a pre determined + or 63 mhz which are transmitted back to and received by the interrogator it is only now that we have a closed loop between the interrogator and the transponder think about it logically you cannot interrogate something unless you have first established communications with that something .therefore simply transmitting in search mode cannot be considered to be an interrogation the loop must be closed first to establish there is a transponder present to interrogate exemple 294 The interrogation does not start before pulse-pairs of the tuned dme-station are received.The interrogation does not start before pulse-pairs of the tuned dme-station are received.

An aeroplane is on approach with nav 1 tuned to the ils frequency and nav 2 ?

Question 186-4 : Quarter scale deflection half scale deflection full scale deflection no deflection

Refer to figure .vors and ilss often use the same displays in the cockpit with the lateral display of the cdi course deviation indicator useful for displaying vor or localiser deviation and the vertical display showing glide path deviation they do not however have the same level of accuracy as a localiser has to be much more accurate than a vor .therefore on a standard 5 dot cdi vors have a deviation indicated by 2 degrees per dot so full scale deflection is 10º deviation from the selected bearing .ils localisers loc on the other hand have just 0 5 degrees per dot deviation so full scale deflection is 2 5º deviation from the localiser centreline .therefore in this scenario where we are on exactly full scale loc deflection we are 2 5º off the correct inbound course which is a quarter of the scale deflection on the vor display exemple 298 Quarter scale deflection.Quarter scale deflection.

Mls is primarily being installed at airports where ?

Question 186-5 : Ils encounters difficulties because of surrounding buildings and/or the terrain or interference from local music stations meteorological conditions are likely to cause ils ducting by super refraction the main approach paths lead over water topographical conditions preclude the installation of ils marker beacons

The microwave landing system mls was designed to replace ils with an advanced precision approach system that would overcome the disadvantages of ils and also provide greater flexibility to its users .however there are few mls installations in use at present and they are likely to co exist with ils for a long time mls is a precision approach and landing system that provides position information and various ground to air data the position information is provided in a wide coverage sector and is determined by an azimuth angle measurement an elevation measurement and a range measurement .mls has the ability to interrupt the transmitted signal to avoid reflection by stationary objects such as obstructions in the appropach path which makes the system less sensitive to geographic location and obstacles this and the relatively low cost of the system are its main advantages .subsidiary advantages are the ability of mls equipped aircraft to fly approach paths other than straight in and the single frequency used avoiding the requirement for frequency pairing exemple 302 Ils encounters difficulties because of surrounding buildings and/or the terrain or interference from local music stations.Ils encounters difficulties because of surrounding buildings and/or the terrain or interference from local music stations.

Concerning adf and ndb ?

Question 186-6 : Ndb is a ground equipment and adf is an airborne equipment adf is a civilian equipment whereas ndb is a military equipment used by civilians too adf is an ground equipment and ndb can be a ground equipment or an airborne equipment ndb is a locator and adf is an en route nav aid

Ndbs are non directional beacons that transmit a simple carrier wave with a modulation to overlay the morse code identifier they are a ground station consisting of just one aerial for transmission .the adf automatic direction finder is the equipment in the cockpit which measures the direction from which the ndb carrier wave signal came and points a needle directly towards the ndb in question on one of the pilot's instruments .ndbs operate between 190 and 1750 khz which spans both the lf low frequency 30 300 khz and mf medium frequency 300 3000 khz frequency bands exemple 306 Ndb is a ground equipment, and adf is an airborne equipment.Ndb is a ground equipment, and adf is an airborne equipment.

The adf indication in the cockpit is a ?

Question 186-7 : Relative bearing on a fixed card indicator magnetic bearing on a fixed card indicator relative bearing on an rmi true bearing on an rmi

Refer to figure . the adf indication on a fixed card inside the cockpit is a rbi relative bearing indicator . the rbi is measured in clockwise direction from the nose of the aircraft exemple 310 Relative bearing on a fixed card indicatorRelative bearing on a fixed card indicator

Night effect in an adf may cause ?

Question 186-8 : Fluctuating indications of the needle on the rmi noise in the received em wave which hardly will be noticed by the pilot looking at the rmi no bearing error because of the built in compensator unit a constant error in the indicated bearing

By day the d region absorbs signals in the lf and mf bands at night the d region disappears allowing sky wave contamination of the surface wave being used .the reason why this arises is because the phase interference of the sky wave with the surface wave because of the different paths and the induction of currents in the horizontal elements of the loop aerial .the effect is manifest by fading of the audio signal and the rmi needle fluctuating is worst around dawn and dusk when the ionosphere is in transition exemple 314 Fluctuating indications of the needle on the rmi.Fluctuating indications of the needle on the rmi.

Which statement is correct with respect to the different types of vor ?

Question 186-9 : A tvor has a limited range a dvor is less accurate than a cvor a cvor is primarily used for instrument approaches a vot is located along an airway with the purpose to provide an in flight check of the airborne equipment

Vor applications.vors are used for en route navigation usually to define airway centrelines .the overall required accuracy of the displayed information is ± 5° .when european airways were first plotted out a lower accuracy of ± 7 5° was assumed .to keep an aircraft within the confines of an airway 10nm maximum distance between the beacons was calculated to be 80nm .vor can be classified as follow .a terminal vor tvor is a low power beacon used as part of an airfield approach tvors share the lower frequencies with ils .a broadcast vor is usually a terminal aid with a voice broadcast giving out the airfield weather atis superimposed on the carrier wave .a test vor vot is a very low power beacon sited at airfields .it puts out a constant phase difference of zero in all directions this allows aircraft to test the accuracy of their equipment on the ground .the vor test function is selected with a course of 000° set .the course deviation indicator should centre with from indicated the rmi should indicate 180° qdm the beacon ident for a test vor is a series of dots exemple 318 A tvor has a limited range.A tvor has a limited range.

On an ils approach when flying overhead the middle marker the colour of the ?

Question 186-10 : Amber blue green white

Refer to figure .there are three types of markers installed as part of a instrument landing system ils .outer marker om .this marker normally indicates the final approach fix faf it is located between 4 and 7 nm from the runway threshold on the same course as the localizer when passing the outer marker the pilot receives an audio tone in continues series of 400 hz accompanied with a flashing blue light in a continuous series of 2 second dashes .middle marker mm .this marker normally indicates the cat i missed approach point and it is positioned between 0 5 and 0 8 nm from the runway threshold when passing the middle marker the pilot receives an audio tone in continues series at 1300 hz accompanied with a flashing amber light in an alternating dots and dashes sequence .inner marker im .this marker normally indicates the passing of the runway threshold when passing the inner marker the pilot receives an audio tone in continues series of 3000 hz accompanied with a flashing white light in a dots sequence exemple 322 Amber.Amber.

On an ils approach when flying overhead the inner marker if available the ?

Question 186-11 : White blue green amber

Refer to figure .there are three types of markers installed as part of a instrument landing system ils .outer marker om .this marker normally indicates the final approach fix faf it is located between 4 and 7 nm from the runway threshold on the same course as the localizer when passing the outer marker the pilot receives an audio tone in continues series of 400 hz accompanied with a flashing blue light in a continuous series of 2 second dashes .middle marker mm .this marker normally indicates the cat i missed approach point and it is positioned between 0 5 and 0 8 nm from the runway threshold when passing the middle marker the pilot receives an audio tone in continues series at 1300 hz accompanied with a flashing amber light in an alternating dots and dashes sequence .inner marker im .this marker normally indicates the passing of the runway threshold when passing the inner marker the pilot receives an audio tone in continues series of 3000 hz accompanied with a flashing white light in a dots sequence exemple 326 White.White.

On final on an ils approach you are flying overhead the outer marker you can ?

Question 186-12 : 4 nm from the threshold 10 nm from the threshold 1 nm from the threshold 25 nm from the threshold

There are three types of markers installed as part of a instrument landing system ils .outer marker om .this marker normally indicates the final approach fix faf .it is located between 4 and 7 nm from the runway threshold on the same course as the localizer when passing the outer marker the pilot receives an audio tone in continues series of 400 hz accompanied with a flashing blue light in a continuous series of 2 second dashes .middle marker mm .this marker normally indicates the cat i missed approach point and it is positioned between 0 5 and 0 8 nm from the runway threshold when passing the middle marker the pilot receives an audio tone in continues series at 1300 hz accompanied with a flashing amber light in an alternating dots and dashes sequence .inner marker im .this marker normally indicates the passing of the runway threshold when passing the inner marker the pilot receives an audio tone in continues series of 3000 hz accompanied with a flashing white light in a dots sequence exemple 330 4 nm from the threshold.4 nm from the threshold.

The uhf band is the assigned frequency band of the ?

Question 186-13 : Ils glide path transmitter all the 3 ils marker beacons outer marker beacon ils localiser transmitter

Refer to figure .as seen in the figure ultra high frequency uhf is along with several others assigned to the ils glide path transmitter exemple 334 Ils glide path transmitter.Ils glide path transmitter.

Ils transmitters use the ?

Question 186-14 : Uhf and vhf bands vhf uhf and hf bands vhf band only uhf band only

Ils main component are .localizer .the localizer loc ground antenna array is located on the extended centerline of the instrument runway of an airport remote enough from the opposite approach end of the runway to prevent it from being a collision hazard .this unit radiates a field pattern which develops a course down the centerline of the runway toward the middle markers mms and outer markers oms and a similar course along the runway centerline in the opposite direction .these are called the front and back courses respectively .the localizer provides course guidance transmitted at 108 1 to 111 95 mhz odd tenths only throughout the descent path to the runway threshold from a distance of 18 nm from the antenna to an altitude of 4 500 feet above the elevation of the antenna site .the localizer course is very narrow normally 5° this results in high needle sensitivity .with this course width a full scale deflection shows when the aircraft is 2 5° to either side of the centerline .this sensitivity permits accurate orientation to the landing runway .with no more than one quarter scale deflection maintained the aircraft will be aligned with the runway .glide slope .glide slope gs describes the systems that generate receive and indicate the ground facility radiation pattern .the glide path is the straight sloped line the aircraft should fly in its descent from where the glide slope intersects the altitude used for approaching the faf to the runway touchdown zone .the glide slope equipment is housed in a building approximately 750 to 1 250 feet down the runway from the approach end of the runway and between 400 and 600 feet to one side of the centerline .the course projected by the glide slope equipment is essentially the same as would be generated by a localizer operating on its side .the glide slope projection angle is normally adjusted to 2 5° to 3 5° above horizontal so it intersects the mm at about 200 feet and the om at about 1 400 feet above the runway elevation .at locations where standard minimum obstruction clearance cannot be obtained with the normal maximum glide slope angle the glide slope equipment is displaced farther from the approach end of the runway if the length of the runway permits or the glideslope angle may be increased up to 4° .marker beacons .all markers operate on 75 mhz vhf thus no frequency selections are necessary for the pilot and radiate a fan shaped field pattern giving to the pilot an indication of range from the threshold .the purpose of the markers is to provide range information while on the approach .they transmit an almost vertical beam almost all installations are equipped with an outer marker and a middle marker .category 2 or 3 ils may be equipped with an inner marker as well .audio and visual signals in the cockpit will indicate when the aircraft is passing overhead .in many installations marker beacons are being replaced or supplemented by the use of a dme associated with the ils exemple 338 Uhf and vhf bands.Uhf and vhf bands.

The localiser transmitters operate in a frequency band between ?

Question 186-15 : 108 mhz and 111 975 mhz 108 mhz and 117 975 mhz 111 975 mhz and 117 975 mhz 329 15 mhz and 335 mhz

Refer to figure .the ils localizer appears in the very high frequency vhf ranging between 108 10 and 111 975 mh exemple 342 108 mhz and 111.975 mhz.108 mhz and 111.975 mhz.

108 35 mhz can only be ?

Question 186-16 : An ils frequency a ndb frequency a vor frequency an atc frequency

The ils localizer frequency appear in the very high frequency vhf ranging between 108 10 and 111 95 mhz .the vor appears in the vhf band typically between 108 00 and 117 95 mhz .. the range between 108 00 and 111 95 mhz is split between the ils and terminal vors so that an even number in the first decimal place is a vor and an odd number is an ils therefore 108 35 mhz is an ils frequency exemple 346 An ils frequency.An ils frequency.

Which statement about adfs is correct ?

Question 186-17 : Adfs can receive and take bearings on any broadcasting station transmitting within the frequency band 190 – 1750 khz adfs cannot receive broadcasting stations transmitting within the frequency band 190 – 1750 khz because ndbs are amplitude modulated and not frequency modulated like broadcasting stations adfs can receive any broadcasting station transmitting within the frequency band 190 – 1750 khz but cannot take bearings on them adfs cannot receive broadcasting stations transmitting within the frequency band 190 – 1750 khz because ndbs are either n0n/a1a or a2a modulated and not a3e modulated like broadcasting stations

Refer to figure .as seen in the figure the adf operates in both the low frequency lf and medium frequency mf band specifically the adf is able to receive bearings between 190 and 1750 khz exemple 350 Adfs can receive and take bearings on any broadcasting station transmitting within the frequency band 190 – 1750 khz.Adfs can receive and take bearings on any broadcasting station transmitting within the frequency band 190 – 1750 khz.

What is the reason that a dme station can generally respond to a maximum of 100 ?

Question 186-18 : The number of reply pulse pairs per second that a dme transponder can transmit is limited to a certain maximum value the minimum allowable accuracy of the range measurement cannot be guaranteed when more than about 100 aircraft are using the same dme station the automatic ground monitoring station of each dme station has a limited capacity the memory of the dme transponder is limited

The response function of a dme transponder involves a continuous process that operates at a transmission rate of 2 700 pairs of pulses per second ppps once the transponder starts receiving pulses at this rate it reaches a state of saturation leading to an automatic reduction in its receiver gain this adjustment has the consequence of filtering out transmissions from aircraft whose interrogation pulses are relatively weaker .in practical terms this translates to approximately 100 aircraft concurrently utilizing the dme system .the fortunate group of 100 consists of those aircraft emitting the most potent interrogation signals rather than necessarily being the closest ones when the ground based dme station undergoes saturation it exclusively acknowledges the 100 most robust signals exemple 354 The number of reply pulse pairs per second that a dme-transponder can transmit is limited to a certain maximum value.The number of reply pulse pairs per second that a dme-transponder can transmit is limited to a certain maximum value.

If the number of pulse pairs received by the dme transponder exceeds the ?

Question 186-19 : The aircraft from which the weakest pulse pairs are received the aircraft at the largest distance from the dme station the aircraft at the lowest altitude the smallest aircraft which is using the dme station for range measurement

Distance measuring equipment dme is a type of secondary radar system that provides slant range using the pulse technique the aircraft’s interrogator transmits a stream of pseudo random omni directional pulse pairs on the carrier frequency of the ground transponder the ground transponder then receives these waits for 50 microseconds and repeats those pulse pairs outwards at a frequency 63 mhz above the interrogation frequency the airborne system identifies its own unique stream of pulse pairs and measures the time of arrival electronically between the start of the interrogation and the reception of the ground transponder's replies given the time delay minus known times such as the 50 microseconds the distance between the aircraft and the dme ground station can be quite precisely calculated as there is only one interrogation frequency and one reply frequency for each dme ground station they can only service a certain number of pulses per second and it ends up meaning that the dme becomes saturated with around 100 aircraft using it and it will then prioritise the pulses with the strongest signal the aircraft that are closer to the ground station and the ones with the stronger transmitting power will therefore be higher priority to be serviced by the dme ground station exemple 358 The aircraft from which the weakest pulse pairs are received.The aircraft from which the weakest pulse pairs are received.

If during an ils approach after having been established the pilot deviates by ?

Question 186-20 : An immediate missed approach should be executed because obstacle clearance may no longer be guaranteed the approach may be completed as long as the associated locator gives the information that the aircraft is on the centre line the approach may be continued but a warning for excessive beam bends should be generated the approach may be continued as long as the gp needle has less than a half scale deflection

The instrument landing system ils is a system that provides the guidance of an aircraft towards the final approach the system provides the aircraft with specific horizontal localizer and vertical glideslope guidance with determining the limits of these guidances there will be a specific area determined which is clear of obstacles .an aircraft that has turned onto the inbound heading and is within 2 5 degrees of the localizer course which means half a scale of deflection on the ils instrument in the cockpit is established on the final approach course .half a scale of deflection are the boundaries of the ils and once going further than half a scale deflection there might not be enough obstacle clearance and a go around should be initiated exemple 362 An immediate missed approach should be executed because obstacle clearance may no longer be guaranteed.An immediate missed approach should be executed because obstacle clearance may no longer be guaranteed.

Fm broadcast stations transmitting just below 108 mhz are ?

Question 186-21 : Likely to cause interference to ils receivers not equipped with an immunity filter causing interference only in extreme cases affecting exclusively the glide path unlikely to cause any interference to ils receivers likely to cause interference to all ils receivers

The instrument landing system ils localizer operates between 108 and 111 975 mhz .fm broadcasting is a method of radio broadcasting using frequency modulation fm fm broadcasting uses the same frequency range as the ils the very high frequency vhf range .the receiving unit of the ils on the aircraft will receive the radio waves that the ils is sending out apart from the correct radiowaves the receiving unit can also receive the broadcasted fm radio signals which will interfere the ils indication and might give false data adding onboard electro magnetic interference emi filters immunity filters or special layout techniques can help in bypassing the interference received from the fm broadcasts exemple 366 Likely to cause interference to ils receivers not equipped with an immunity filter.Likely to cause interference to ils receivers not equipped with an immunity filter.

The definition of the term qdr is… ?

Question 186-22 : The magnetic bearing from the station the magnetic bearing to the station the true bearing to the station the true bearing from the station

Refer to figure . .as seen in the figure there is a system of abbreviations that indicates what kind of bearing is described .qdm = magnetic bearing to the station . .qdr = magnetic bearing from the station . .quj = true bearing to the station . .qte = true bearing from the station exemple 370 The magnetic bearing from the stationThe magnetic bearing from the station

Reflections from large objects within the ils coverage area may cause ?

Question 186-23 : Multi path interference doppler errors single path interference static noise

An instrument landing system ils consists of a localizer and a glide path this system needs to be installed in possibly uneven terrain uneven terrain might interfere with the ils .multipath interference to ils depends on the type of antenna used and any large reflecting objects in the area like mountains moving objects can degrade the directional signals that the interference on the system will be too high to be tolerated exemple 374 Multi-path interference.Multi-path interference.

The accuracy the pilot has to fly the required bearing in order to be ?

Question 186-24 : 5° 2 5° 2° 7 5°

A non directional beacon ndb is a ground based low frequency radio transmitter used as an instrument approach for airports and offshore platforms .the ndb transmits an omni directional signal that is received by the adf or automatic direction finder a standard instrument onboard aircraft the pilot uses the adf to determine the direction to the ndb relative to the aircraft .a non precision approach is an instrument approach and landing which utilises lateral guidance but does not utilise vertical guidance icao annex 6 .non precision approaches which are pilot interpreted make use of ground beacons and aircraft equipment such as vhf omnidirectional radio range vor non directional beacon and the llz element of an ils system often in combination with distance measuring equipment dme for range .lateral guidance is provided by a display of either bearing to/from a radio beacon on the approach track or at the airfield or in the case of an llz only approach by display of the relative position of the llz track on the aircraft ils instruments and vertical guidance is based on the range from the airfield as indicated by a dme at the airfield or on track or by timing based upon passage overhead radio beacons on the track described by the designated procedure .remember in terms of lateral errors permitted flying an ndb npa you must maintain a qdm/qdr that is ± 5° of the designated approach exemple 378 5°5°

With respect to the monitoring system of a vor which statement is correct ?

Question 186-25 : Failure of the vor station to stay within the required limits can cause the removal of identification and navigation components from the carrier or radiation to cease failure of the vor station to stay within the required limits will trigger a vor caution annunciator in the cockpit the system monitors directly the phase of the reference signal and the phase of the variable signal if the monitoring system detects a change in the measured radial the transmission power will be reduced and consequently only aircraft in the terminal area can use the vor

All vor beacons are monitored by an automatic site monitor the monitor will warn the control point and remove either the identification and the navigational signals or switch off the beacon in the event of the following . bearing information change exceeding 1°. a reduction of more than 15% in signal strength. a failure of the monitor exemple 382 Failure of the vor station to stay within the required limits can cause the removal of identification and navigation components from the carrier or radiation to cease.Failure of the vor station to stay within the required limits can cause the removal of identification and navigation components from the carrier or radiation to cease.

Which frequency can be used by a terminal vor ?

Question 186-26 : 108 20 mhz 111 975 mhz 118 15 mhz 108 10 mhz

Refer to figure .as seen in the table the vor vhf omnidirectional range uses the very high frequency vhf band to transmit it’s electromagnetic waves terminal vor uses specific frequencies vor uses even decimals and even decimals plus 0 05 mhz for example 108 0 108 005 108 20 108 25 108 40 108 45 etc exemple 386 108.20 mhz.108.20 mhz.

A pilot is tracking inbound to a vor on a designated radial using the hsi the ?

Question 186-27 : Scalloping night effect quadrantal error coastal refraction

Site error is caused by uneven terrain for example hills trees buildings and long grass near the transmitter although the propagation has left the vor with ±1° accuracy propagation error still exists propagation error is caused by the terrain and distance at a certain range from the vor so called ‘bends’ or ‘scalloping’ can occur vor scalloping is described as an imperfection or deviation in the received vor signal scalloping causes the signal to bend as a result of reflections from buildings and terrain scalloping also causes the course deviation indicator cdi to slowly or rapidly shift from side to side scalloping has a negative effect on the accuracy of the navigation aids used exemple 390 ScallopingScalloping

The magnetic variation to convert the rmi bearings of ndbs and vors to true ?

Question 186-28 : Aircraft position for ndbs and at the beacon position for vors aircraft position for ndbs and at the aircraft position for vors beacon position for ndbs and at the beacon position vors beacon position for nds and at the aircraft position for vors

An important fact is that the vor radial information is determined at the vor station – therefore if you need to convert between true and  magnetic when dealing with vor bearings you have to apply the value of magnetic variation valid at the place of the vor station for ndb/adf bearings is the opposite the bearings are taken at the aircraft therefore the magnetic variation applicable at the aircraft’s position is to be used exemple 394 Aircraft position for ndbs and at the beacon position for vors.Aircraft position for ndbs and at the beacon position for vors.

The frequency range of a vor receiver is ?

Question 186-29 : 108 to 117 95 mhz 118 to 135 95 mhz 108 to 135 95 mhz 108 to 111 95 mhz

Refer to figure .as seen in the table the vor vhf omnidirectional range uses the very high frequency vhf band to transmit it’s electromagnetic waves vor beacons operate between 108 0 and 117 95 mhz exemple 398 108 to 117.95 mhz108 to 117.95 mhz

Which of the following is the icao allocated frequency band for aeronautical ?

Question 186-30 : 190 khz to 1750 khz 300 khz to 3000 khz 200 khz to 2000 khz 255 khz to 455 khz

Refer to figure .as seen in the figure the non directional beacon ndb operates in both the low frequency lf and medium frequency mf band the ndb is able to receive bearings between 190 and 1750 khz exemple 402 190 khz to 1750 khz190 khz to 1750 khz

Errors caused by the effect of coastal refraction on bearings at lower ?

Question 186-31 : Inland and the bearing crosses the coast at an acute angle near the coast and the bearing crosses the coast at an acute angle near the coast and the bearing crosses the coast at right angles inland and the bearing crosses the coast at right angles

The effect of coastal refraction can be minimized by flying higher .naturally when flying lower the coastal refraction experienced will be worse .radio waves speed up over water causing the wave front to bend away from its normal path and pull it towards the coast .coastal refraction is negligible when the aircraft is perpendicular 90° to the coast the coastal refraction increases as the angle to which the aircraft cuts the shoreline decreases exemple 406 Inland and the bearing crosses the coast at an acute angle.Inland and the bearing crosses the coast at an acute angle.

The dme distance measuring equipment operates in which frequency range ?

Question 186-32 : 960 to 1215 mhz 329 to 335 mhz 108 to 118 mhz 960 to 1215 khz

Distance measuring equipment dme is defined as a combination of ground and airborne equipment which gives a continuous slant range distance from station readout by measuring time lapse of a signal transmitted by the aircraft to the station and responded back .dmes can also provide groundspeed and time to station readouts by differentiation .the dme will measure the distance in a straight line to the ground beacon the slant range not the distance from a point on the ground vertically below the aircraft ground range the difference is generally insignificant except that when directly over a beacon when the distance shown will be height above the beacon .dme operates in the ultra high frequency uhf band and the 252 available channels are contained between 960 and 1215 mhz .it utilises a double pulse in both the interrogator and the transponder all pulses are the same duration that is 3 5 micro seconds .discrimination between channels is accomplished by both frequency separation and pulse spacing .channels are numbered from 1 to 126 and each channel number is further divided into two channels designated ‘x’ and ‘y’ .each numbered pair of channels is separated from the adjoining pair by 1 mhz the ‘x’ channels are separated from the ‘y’ channels by varying the pulse separation time the pulse separation spacing is the same for all ‘x’ channels being 12 micro seconds for both the interrogator and the transponder .in the case of ‘y’ channels the pulse spacing is 36 micro seconds for the interrogator and 30 micro seconds for the transponder exemple 410 960 to 1215 mhz960 to 1215 mhz

The frequency of the amplitude modulation and the colour of an ils outer marker ?

Question 186-33 : 400 hz and blue 400 hz and amber 3000 hz and blue 1300 hz and blue

Outer marker om .this marker normally indicates the final approach fix faf it is located between 4 and 7 nm from the runway threshold on the same course as the localizer .when passing the outer marker the pilot receives an audio tone in continues series of 400 hz accompanied with a flashing blue light in a continuous series of 2 second dashes exemple 414 400 hz and blue.400 hz and blue.

A dvor is less sensitive to site errors than a cvor because ?

Question 186-34 : The variable phase is frequency modulated rather than amplitude modulated of the presence of a monitoring system of the smaller vor antenna of the use of vertical polarised waves instead of horizontal polarised waves

Refer to figure . vor ground stations transmit two separate signals one is the reference signal and the other is the variphase signal the principle of operation of conventional vors cvors is that the reference signal is omnidirectional so all positions receive the signal equally but the variphase signal is transmitted by a spinning antenna so it appears at each position radial at a different time in comparison to the reference signal radio waves like this are not pulses though they are continuous sine waves therefore the difference we measure between the reference signal and the variphase signal is a phase difference simply put a timing difference that can be measured to give the receiver their vor radial the two signals are easy to compare against each other as they are the same frequency but differently modulated so both can be picked up separately in a cvor the reference signal is fm frequency modulated and the variphase signal is am amplitude modulated in a dvor the reference signal is am and the variphase signal is fm dvor stands for doppler vor and they are much bigger ground units with larger antennas that use the opposite modulation to cvors and their variphase signal comes from a single omnidirectional signal that is sent to a ring of different antennas see annex above one at a time travelling round the circle to create a virtual 'travelling antenna' this causes a doppler frequency shift of the signal depending on the aircraft's vor radial this can then be compared to the am reference signal in the same airborne receivers as for cvors to provide a radial which is then used in standard vor displays because the aircraft does not know which type it is using dvors are slightly modified signal spins the opposite direction so it acts the same as a cvor to a receiver dvors are more common these days as they are less prone to site errors due to multipath errors and interference this is because their variphase signal is fm which is much less prone to interference from other signals that bounce off surfaces nearby to the line of sight signal amplitude modulation on the other hand has some strong interference effects from interference and reflected radio waves as the variphase signal is the one which counts in this respect for reasons well above the syllabus dvors are less prone to site and multipath errors note in the past a question like this has been seen that mention larger more powerful signals as the reason dvors are better this is not true as bigger antennas will help a little bit but that is not the primary reason they are less prone to errors than cvors exemple 418 The variable phase is frequency modulated rather than amplitude modulated.The variable phase is frequency modulated rather than amplitude modulated.

The ils receiver of an aircraft on approach and flying to the right of the ?

Question 186-35 : More of the 150 hz localiser signal than the 90 hz localiser signal the left lobe modulation only a modulated signal that will move the localiser needle to the right according to the magnitude of the difference between the two amplitudes the modulation from both lobes at equal amplitude

Refer to figure .as seen in the figure the localizer as part of the ils covers the lateral area in front of the runway which ever lobe the aircraft is closest to will receive a greater strength .if the aircraft is to the left of the runway centre line it will receive a greater strength from the 90 hz lobe than from the 150 hz lobe .if the aircraft is to the right of the runway centreline line it will receive a greater strength from the 150 hz lobe than from the 90 hz lobe this is the principle of how the localizer works exemple 422 More of the 150 hz localiser signal than the 90 hz localiser signal.More of the 150 hz localiser signal than the 90 hz localiser signal.

Regarding ils operations which of the following circumstances will trigger ?

Question 186-36 : 2 and 4 3 and 4 1 and 3 1 and 2

Warning flags on an ils will be triggered because of the absence of the lobes only when in reach of the localizer and glideslope the lobes of 90 hz and 150 hz will be correctly read .. . this will not trigger a warning this will simply indicate that the aircraft is on the ideal 3° glideslope and perfectly on the runway centre line . . . warning flags will be triggered when either the glideslope or the localizer is out of the reach and there might be a risk of false lobes . . . the cloud base does not have influence on the correct operation of the ils the lobes work regardless of the weather . . . warning flags will be triggered when the modulation depth of both the localizer and glideslope are reduced to zero meaning that there’s no correct indication available exemple 426 2 and 42 and 4

An aircraft tracking to intercept the instrument landing system ils localiser ?

Question 186-37 : May receive false course indications can expect signals to give correct indications only glide path information is available will receive signals without identification coding

The localizer coverage area extends to a maximum angle of 35° of the localizer centreline outside the coverage area the aircraft will receive a faulty localizer signal these signals are called false courses and may lead to trouble because the aircraft will not receive the proper guidance towards the runway .false courses are a byproduct of the ils signals and are created at all angles outside the coverage area during maintenance of the ils false courses might also be generated inside the coverage area which is why the ils will be unserviceable out of use when maintenance is being performed exemple 430 May receive false course indications.May receive false course indications.

An aircraft at fl300 in isa conditions and with a ground speed of 300 kt is ?

Question 186-38 : Less than 300 kt and 7 nm less than 300 kt and 5 nm 300 kt and 5 nm 300 kt and 7 nm

Refer to figure .important to know with this question is that the groundspeed is only accurate when the aircraft is flying directly towards or away from the dme station meaning that the indication given by the dme will usually be less than what the aircraft is actually flying ..the dme on board the aircraft will indicate the purple slant range .the aircraft is 1 minute from the dme meaning that the ground distance towards the station will be .. . . 300 nm. 60 min. . . . 1 min. . ....  = 1min x 300 nm / 60 min = 5 nm .knowing that the ground distance to the station is 5 nm the slant range dme indication can be calculated by using the following .fl300 = 30 000 ft = 4 9 nm = 5 nm ..the slant range can be used by using the following the pythagoras theorem .slant range = ground distance ²+ aircraft height 2 .slant range = 5 nm ²+ 5 nm ² = 7 nm exemple 434 Less than 300 kt and 7 nm.Less than 300 kt and 7 nm.

An ils glide path provides azimuth coverage i each side of the localiser ?

Question 186-39 : I 8° ii 10 i 25° ii 17 i 35° ii 25 i 5° ii 8

Refer to figure .localiser coverage.. . from the center of the localiser aerial to 25 nm within ±10° of the approach bearing . . . from the center of the localiser aerial out to a distance of 17 nm within ±35° of the approach bearing . . . in some regions where a steep angle glidepath is authorised coverage is provided from the center of the localiser aerial to 18 nm ±10° and 10 nm ±35° . . . upper limit of the localizer signal vertical coverage is a minimum of 7° above the localizer horizontal plane . . . the protection range and height of ils is 25 nm / 6 250 ft . ..note 1 any attempt to use the localiser outside the areas listed above may lead to false/reverse sense indications use outside designated coverage areas is therefore not permitted .glidepath coverage.. . vertical coverage from 0 45 to 1 75 above the horizontal through the ils threshold = glide path angle this equates to 1 35° to 5 25° above the threshold horizontal for a nominal 3° glide path . . . horizontal coverage extending in azimuth 8° either side of the extended centerline out to a range of 10 nm . . . the protection range and height of ils is 25 nm / 6 250 ft . ..note 2 example of the glideslope vertical coverage calculation for a glideslope of 3 3° the vertical coverage is as follows .. . 0 45 × 3 3° = approx 1 49° lower edge . . . 1 75 × 3 3° = approx 5 77° upper edge exemple 438 (i) 8° (ii) 10(i) 8° (ii) 10

The vor radial an aircraft is on depends upon ?

Question 186-40 : The phase difference between the reference and variable phases the difference between the selected radial and the radial the aircraft is on the difference between the selected course and the radial the aircraft is on the time difference between the reference and variable phases

A vhf omni directional range vor is used as a navigation beacon for aircraft aircraft with a receiving unit will be able to determine their position relative to the vor ground station the ground station sends a highly directional signal by making use of a so called phased array antenna together with this signal the vor sends a 30 hz reference signal which is equal in all direction .the phase difference between the reference signal and the highly directional signal is the bearing from the vor station relative to magnetic north .a vor receiver works by comparing the phase relationship between a reference signal and a variable signal exemple 442 The phase difference between the reference and variable phases.The phase difference between the reference and variable phases.

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