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Question 200-1 : The magnetic variation to convert the rmi bearings of ndbs and vors to true bearings will occur at the ? [ Exam pilot ]

Aircraft position for ndbs and at the beacon 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 300 Aircraft position for ndbs and at the beacon position for vors.

Question 200-2 : The frequency range of a vor receiver is ?

108 to 117 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 304 108 to 117.95 mhz

Question 200-3 : Which of the following is the icao allocated frequency band for aeronautical ndbs ?

190 khz to 1750 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 308 190 khz to 1750 khz

Question 200-4 : Errors caused by the effect of coastal refraction on bearings at lower altitudes are maximum when the ndb is ?

Inland and the bearing crosses the coast at an acute angle

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 312 Inland and the bearing crosses the coast at an acute angle.

Question 200-5 : The dme distance measuring equipment operates in which frequency range ?

960 to 1215 mhz

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 316 960 to 1215 mhz

Question 200-6 : The frequency of the amplitude modulation and the colour of an ils outer marker om light is ?

400 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 320 400 hz and blue.

Question 200-7 : A dvor is less sensitive to site errors than a cvor because ?

The variable phase is frequency modulated rather than amplitude modulated

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 324 The variable phase is frequency modulated rather than amplitude modulated.

Question 200-8 : The ils receiver of an aircraft on approach and flying to the right of the runway centreline will receive ?

More of the 150 hz localiser signal than the 90 hz localiser signal

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 328 More of the 150 hz localiser signal than the 90 hz localiser signal.

Question 200-9 : Regarding ils operations which of the following circumstances will trigger warning flags for the llz and the gp .1 the measured ddm is zero . .2 the absence of the 90 hz and 150 hz modulation simultaneously . .3 the cloud base as reported by the atis is below landing minima . .4 the modulation ?

2 and 4

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 332 2 and 4

Question 200-10 : An aircraft tracking to intercept the instrument landing system ils localiser inbound on the approach side outside the published ils coverage angle ?

May receive false course indications

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 336 May receive false course indications.

Question 200-11 : An aircraft at fl300 in isa conditions and with a ground speed of 300 kt is about pass overhead a dme station at msl the dme receiver is capable of determining ground speed one minute before the overhead dme speed and distance indications are respectively ?

Less than 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 340 Less than 300 kt and 7 nm.

Question 200-12 : An ils glide path provides azimuth coverage i each side of the localiser centreline to a distance of ii nm from the threshold ?

I 8° ii 10

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 344 (i) 8° (ii) 10

Question 200-13 : The vor radial an aircraft is on depends upon ?

The phase 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 348 The phase difference between the reference and variable phases.

Question 200-14 : Which of the following errors affects the use of vor ?

Scalloping

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 352 Scalloping

Question 200-15 : How can a dme interrogator distinguish between its own reply pulse pairs and the reply pulse pairs of other aircraft in the area using the same dme station ?

The pulse repetition frequency of the pulse pairs transmitted by the interrogator varies for each interrogator in a unique rhythm

Dme uses the uhf frequency band between 962 1213 mhz the aircraft dme equipment radiated coded pulse pairs which is then received at the ground station triggering the transponder to send a suitably formatted reply adjusted by +/ 63 mhz after a delay of 50 microseconds for each of the interrogation channels two reply frequencies are allocated one is 63 mhz higher than the transmission and the other 63 mhz lower the reason for using pulse pairs is to ensure the receivers do no accept random single pulses or other transmissions that are not addressed for this type of communication each pulse pair is spaced at 12 microseconds x channels or 36 microseconds y channels and the space of each pair of pulse pairs is different between each group and is randomly unique to each transmission exemple 356 The pulse repetition frequency of the pulse pairs transmitted by the interrogator varies, for each interrogator, in a unique rhythm.

Question 200-16 : Which of the following alternatives is correct regarding audio and visual signals in the cockpit when passing overhead an ils middle marker ?

Audio 1300 hz alternating dots and dashes visual amber light flashes

The outer marker middle marker and inner marker all emit an amplitude modulated horizontally polarised signal the beacons operate at a 75 mhz carrier frequency outer marker om to provide height distance and equipment function checks for aircraft on final approach aural identification a 400 hz low pitch tone keyed in a form of 2 dashes per second visual representation lights bluemiddle marker mm indicated the imminence of transition to visual guidance often defines the decision point aural identification a 1300 hz medium pitch tone keyed in a form of alternating dots and dashes with 3 dashes per second visual representation lights amberinner marker im indicates the imminence of arrival above the threshold aural identification a 3000 hz tone keyed continuous dots at a rate of 6 dots per second visual representation lights white exemple 360 Audio: 1300 hz, alternating dots and dashes. visual: amber light flashes.

Question 200-17 : Of the approach aids listed below which option correctly identifies those that use the vhf band .1 locator . .2 localiser . .3 outer marker . .4 glide path ?

Only 2 and 3

Locators operate on a frequency between 190 and 1750khz lf and mf . localiser operates on a frequency between 108 10 and 111 96 mhz vhf . marker beacons operate on a frequency of 75 mhz vhf . glide path operates on a frequency 328 6 and 335 4 mhz uhf exemple 364 Only 2 and 3

Question 200-18 : Middle marker beacons of an ils transmit at ?

75 mhz

All ils marker beacons 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 .the outer marker is located approximately 3 9 nautical miles from the runway threshold and is aligned across the front beam of the localiser its purpose is to provide height distance and equipment functioning checks to aircraft on final approach it is modulated at 400 hertz and keyed to transmit dashes continuously at a rate of 2 per second .the middle marker is aligned across the front beam of the localiser and is situated approximately 1050 metres from the runway threshold its purpose is to indicate the imminence in low visibility conditions of visual approach guidance this marker is modulated at 1300 hertz and keyed to transmit alternate dots and dashes · · · the rate is 2 dashes and 6 dots per second an aircraft on the glide slope over the middle marker should be roughly 200 feet above the touchdown zone elevation .the inner marker is modulated at 3000 hertz identified by a keyed continuous signal of 6 dots per second · · · · · and is located 75–450 metres from the runway threshold .summary .. . outer marker identifies glideslope intercept or the final approach fix light flashes blue . . . middle marker identifies decision height light flashes amber . . . inner marker identifies decision height for a cat ii ils light flashes white exemple 368 75 mhz.

Question 200-19 : The ils marker identified audibly by a series of dots 6/second is the… ?

Inner marker

The outer marker middle marker and inner marker all emit an amplitude modulated horizontally polarised signal the beacons operate at a 75 mhz carrier frequency outer marker om to provide height distance and equipment function checks for aircraft on final approach aural identification a 400 hz low pitch tone keyed in a form of 2 dashes per second visual representation lights bluemiddle marker mm indicated the imminence of transition to visual guidance often defines the decision point aural identification a 1300 hz medium pitch tone keyed in a form of alternating dots and dashes with 3 dashes per second visual representation lights amberinner marker im indicates the imminence of arrival above the threshold aural identification a 3000 hz tone keyed continuous dots at a rate of 6 dots per second visual representation lights white exemple 372 Inner marker.

Question 200-20 : The ils marker identified audibly by a series of alternate dots and dashes is the… ?

Middle marker

The outer marker middle marker and inner marker all emit an amplitude modulated horizontally polarised signal the beacons operate at a 75 mhz carrier frequency outer marker om to provide height distance and equipment function checks for aircraft on final approach aural identification a 400 hz low pitch tone keyed in a form of 2 dashes per second visual representation lights bluemiddle marker mm indicated the imminence of transition to visual guidance often defines the decision point aural identification a 1300 hz medium pitch tone keyed in a form of alternating dots and dashes with 3 dashes per second visual representation lights amberinner marker im indicates the imminence of arrival above the threshold aural identification a 3000 hz tone keyed continuous dots at a rate of 6 dots per second visual representation lights white exemple 376 Middle marker.

Question 200-21 : The audio frequency modulation of the middle marker shall be keyed as follows… ?

A continuous series of alternate dots and dashes

The outer marker middle marker and inner marker all emit an amplitude modulated horizontally polarised signal the beacons operate at a 75 mhz carrier frequency outer marker om to provide height distance and equipment function checks for aircraft on final approach aural identification a 400 hz low pitch tone keyed in a form of 2 dashes per second visual representation lights bluemiddle marker mm indicated the imminence of transition to visual guidance often defines the decision point aural identification a 1300 hz medium pitch tone keyed in a form of alternating dots and dashes with 3 dashes per second visual representation lights amberinner marker im indicates the imminence of arrival above the threshold aural identification a 3000 hz tone keyed continuous dots at a rate of 6 dots per second visual representation lights white exemple 380 A continuous series of alternate dots and dashes.

Question 200-22 : The ils outer marker modulation frequency is ?

400 hz

All ils marker beacons 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 .the outer marker is located approximately 3 9 nautical miles from the runway threshold and is aligned across the front beam of the localiser .its purpose is to provide height distance and equipment functioning checks to aircraft on final approach .it is modulated at 400 hertz and keyed to transmit dashes continuously at a rate of 2 per second .the middle marker is aligned across the front beam of the localiser and is situated approximately 1050 metres from the runway threshold .its purpose is to indicate the imminence in low visibility conditions of visual approach guidance .this marker is modulated at 1300 hertz and keyed to transmit alternate dots and dashes · · · .the rate is 2 dashes and 6 dots per second .an aircraft on the glide slope over the middle marker should be roughly 200 feet above the touchdown zone elevation .the inner marker is modulated at 3000 hertz identified by a keyed continuous signal of 6 dots per second · · · · · and is located 75–450 metres from the runway threshold .summary .. . outer marker identifies glideslope intercept or the final approach fix light flashes blue . . . middle marker identifies decision height light flashes amber . . . inner marker identifies decision height for a cat ii ils light flashes white exemple 384 400 hz.

Question 200-23 : According to the principle of operation in an ils the difference in depth of modulation will ?

Increase with displacement from the centreline

Refer to figure .the difference in depth modulation ddm is a principle used by the ils to define a position in an airspace the deviation detection of the aircraft from the desired track is based on two different overlapping lobes these lobes are radiated by both the localiser and the glide path antennas these consist of a 90 hz lobe and a 150 hz lobe .for the glide path .. . when the airborne receiver receives a stronger signal from the 90 hz lobe than the 150 hz lobe it means that the aircraft is above the ‘ideal’ glideslope . . . when the airborne receiver receives a stronger signal from the 150 hz lobe than the 90 hz lobe the aircraft will be below the ‘ideal’ glideslope . . . when both the signals received are at the same strength it means the aircraft will be on the ‘ideal’ glideslope and the glideslope needle will indicate zero . ..for the localiser the same method is used stronger signals from the 90 hz lobe means a displacement to the left whereas stronger signals from the 150 hz lobe means a right displacement in relation to the centreline when both the signals received are at the same strength it means the aircraft will be on the centreline and the localiser needle will indicate zero ..assume that you are on the centreline if you move away from the centrelline however still in the range of the localizer the ddm will increase ..ddm = am 90 hz am 150 hz / 100.therefore once you go off centreline either the 90 or 150 increases causing ddm to increase negative is also assumed to be an increase exemple 388 Increase with displacement from the centreline.

Question 200-24 : The type of modulation of the ils frequency carrier is ?

Amplitude modulation

The modulation type of all ils transmitters is the good old amplitude modulation am the carrier oscillation in the localizer frequency range is 108 00 mhz to 111 975 mhz modulated with a 90hz and a 150hz tone signal .the ils works by sending 2 beams up from the landing runway one telling the pilots if they or high or low and the other telling them if they are left or right of the runway centreline the ils receiver on the aircraft measures the difference in depth of modulation ddpm between the signals for most ils’s the pilots should be lined up with the runway centreline and on a 3 degree glide path but on some ils’s like london city have a steeper approach of 5 5 degrees .this two modulated signals are produced from a horizontally polarized antenna complex beyond the far end of the approach runway they create an expanding field that is 21 2° wide about 1 500 feet 5 miles from the runway the field tapers to runway width near the landing threshold the left side of the approach area is filled with a vhf carrier wave modulated with a 90 hz signal the right side of the approach contains a 150 mhz modulated signal the aircraft’s vor receiver is tuned to the localizer vhf frequency that can be found on published approach plates and aeronautical charts the circuitry specific to standard vor reception is inactive while the receiver uses localizer circuitry and components common to both the signals received are passed through filters and rectified into dc to drive the course deviation indicator if the aircraft receives a 150 hz signal the cdi of the vor/ils display deflects to the left this indicates that the runway is to the left the pilot must correct course with a turn to the left this centers course deviation indicator on the display and centers the aircraft with the centerline of the runway if the 90 hz signal is received by the vor receiver the cdi deflects to the right the pilot must turn toward the right to center the cdi and the aircraft with the runway center line annex1 .like the localizer the glideslope transmits two signals one modulated at 90 hz and the other modulated at 150 hz the aircraft’s glideslope receiver deciphers the signals similar to the method of the localizer receiver it drives a vertical course deviation indicator known as the glideslope indicator the glideslope indicator operates identically to the localizer cdi only 90° to it the vor/ils localizer cdi and the glideslope are displayed together on whichever kind of instrumentation is in the aircraft annex2 exemple 392 Amplitude modulation.

Question 200-25 : One of the possible disturbances of the ils signal is 'scalloping' which statement is correct ?

Scalloping causes rapid indicator changes from side to side of the intended approach path which cannot be followed by the aircraft

Scalloping is a type of error in radio signal transmission which causes oscillatory propagation distortion due to presence of ground and/or atmospheric conditions it results in rapid fluctuations of the needles on the cdi/hsi which are impossible to follow exemple 396 Scalloping causes rapid indicator changes from side to side of the intended approach path which cannot be followed by the aircraft.

Question 200-26 : What is the reason that dme utilises pulse pairs instead of single pulses ?

To distinguish dme transmissions from transmissions of other radar systems utilising single pulses

Dme uses the uhf frequency band between 962 1213 mhz the aircraft dme equipment radiated coded pulse pairs which is then received at the ground station triggering the transponder to send a suitably formatted reply adjusted by +/ 63 mhz after a delay of 50 microseconds for each of the interrogation channels two reply frequencies are allocated one is 63 mhz higher than the transmission and the other 63 mhz lower the reason for using pulse pairs is to ensure the receivers do no accept random single pulses or other transmissions that are not addressed for this type of communication each pulse pair is spaced at 12 microseconds x channels or 36 microseconds y channels and the space of each pair of pulse pairs is different between each group and is randomly unique to each transmission exemple 400 To distinguish dme transmissions from transmissions of other (radar) systems utilising single pulses.

Question 200-27 : If two dme ranges are plotted on the chart and used to fix the aircraft position what would be indicated on the chart ?

Two circular position lines intersecting at two points the distance from each transmitter being the slant range

Refer to figure .the dme displays distance information from a fix this distance being the slant range between the transmitter and the aircraft the position of the aircraft may be anywhere on a circle with the dme in the centre with a radius that is the range from the dme two overlapping circles will intersect at two points exemple 404 Two circular position lines intersecting at two points, the distance from each transmitter being the slant range.

Question 200-28 : Which option correctly identifies the approach aid s listed below to which the uhf band is assigned .1 locator . .2 localiser . .3 outer marker . .4 glide path ?

Only 4

Locators operate on a frequency between 190 and 1750khz mf localiser operates on a frequency between 108 10 and 111 96 mhz vhf marker beacons operate on a frequency of 75 mhz vhf glide path operates between the frequencies 328 6 and 335 4 mhz uhf exemple 408 Only 4.

Question 200-29 : What radio navigation aid would be associated with the transmission frequency 110 35 mhz ?

Ils localiser

108 mhz and 112 mhz frequency band is shared between ils and vor frequencies .from 112 mhz to 117 975 mhz the band belongs to vor alone and spacing is reduced to 50 khz thus 108 2 mhz and 113 35 mhz would be vor frequencies and 108 1 mhz would not .within the vor ils shared frequency range the allocated frequencies are as follows .vor = even 100 khz numerals.108 00 108 05 108 20 108 25 to 111 80 111 85.ils = odd 100 khz numerals.108 10 108 15 108 30 108 35 to 111 90 111 95 so 110 35 is between them exemple 412 Ils localiser

Question 200-30 : To enter a holding pattern based on a vor/dme fix which entry sectors are permissible when following a dme arc entry track sectors ?

1 and 3

Refer to figure .icao doc 8168.1 4 7 dme arc entry.dme arc entry at the fix the aircraft shall enter the holding pattern in accordance with either the sector 1 or sector 3 entry procedure ..sector 1 procedure => parallel entry .sector 2 procedure => offset entry .sector 3 procedure => direct entry exemple 416 1 and 3.

Question 200-31 : On an ils approach when flying overhead the outer marker the colour of the flashing light will be… ?

Blue

The outer marker middle marker and inner marker all emit an amplitude modulated horizontally polarised signal the beacons operate at a 75 mhz carrier frequency outer marker om to provide height distance and equipment function checks for aircraft on final approach aural identification a 400 hz low pitch tone keyed in a form of 2 dashes per second visual representation lights bluemiddle marker mm indicated the imminence of transition to visual guidance often defines the decision point aural identification a 1300 hz medium pitch tone keyed in a form of alternating dots and dashes with 3 dashes per second visual representation lights amberinner marker im indicates the imminence of arrival above the threshold aural identification a 3000 hz tone keyed continuous dots at a rate of 6 dots per second visual representation lights white exemple 420 Blue.

Question 200-32 : Mls installations notified for operation unless otherwise stated provide azimuth coverage of ?

±40° about the nominal course line out to a range of 20 nm

Refer to figure . the icao annex 10 declares a requirement for a minimum coverage area within which the mls must provide full serviceability for the approach a wide area is allocated for mls precision navigation that is a circular arc with a 20 nm radius from the threshold with ± 40º from the transmitter in each direction of the runway centreline exemple 424 ±40° about the nominal course line out to a range of 20 nm.

Question 200-33 : There are two ndbs one 20 nm inland and the other 50 nm inland from the coast assuming that the error caused by coastal refraction is the same for both propagations the extent of the error in a position line plotted by an aircraft that is over water will be ?

Greater from the beacon that is 50 nm inland

Refer to figure .ndbs send out low or medium frequency radio waves they actually generate two waves a ground wave that follows the earth and a sky wave that bounces off of the ionosphere in this case were only talking about the ground wave .when the ground wave crosses a shoreline and moves out to sea it bends towards the coast .coastal refraction changes in conductivity from land to sea.electrical differences between land and sea affect radio waves .as low frequency waves cross the shoreline they move abruptly from an area of low conductivity land to an area of high conductivity water .that rapid change in conductivity changes the radio wave's 'phase velocity '.what's that imagine the crest of a wave moving across the ocean the speed that the crest moves is the wave's phase velocity .radio waves are no different .as the phase velocity changes the wave's frequency what you dialed into the radio receiver stays the same .to decrease this error pilot must use .. . stations closer to the coast . . . stations that produce signal crossing the cost line as close to 90° as possible. . . use higher cruising altitude as the refraction error decreases with altitude. ..note the laws of conservation of energy and momentum come into play and the wave bends this is called refraction for a more in depth look at the physics check out snell's law exemple 428 Greater from the beacon that is 50 nm inland

Question 200-34 : When an ndb fails which kind of warning is visible in the cockpit ?

No warning

Ndb failure warning.unline vor or ils systems that have failure warning indications the ndb does not warn the pilot in the case of a failure the ndb is a simple transmitter the adf receives the signal and displays the direction of the radio source since adf receivers do not have a 'flag' to warn the pilot when erroneous bearing information is being displayed the pilot should continuously monitor the ndb's identification when the ndb itself fails the pilot might notice a searching needle on their display much line when it is out of range of the receiver exemple 432 No warning.

Question 200-35 : The dme line of position is a circle with radius ?

A the ground distance and centre the dme station

A dme is used for determining the distance from a ground dme transmitter compared to other vhf/uhf navaids a dme is very accurate the distance information can be used to determine the aircraft position or flying a track that is a constant distance from the station this is referred to as a dme arc .there are several way to plot a route on a chart .. . straight route plotted between radio beacons. . . direct route plotted without reference to any paricular radio beacons and fixes are calculated along the track based on position lines plotted from radio beacons. ..in general a position line is a circle with radius the ground distance between the point and the ground station and centre at the ground station .pay attention there are some quite similar questions regarding dme poistion lines with very different answer the main problem is about the dme distance should a pilot consider dme distace plotted on a chart like a slant or a ground range distance .in general we can affirm that there is a difference between ground range and slant range but that difference is negligible and not worth considering until you are very close to the beacon at which point plotting becomes quite immaterial and difficult owing to the relatively rapid changes in distance i e 3 nm change in range is not significant when 150 nm from the beacon but it is significant when you are only 5 nm from the beacon .as a rule of thumb discrepancies only start to appear within 1 nm per 1 000' of height e g when flying at 10 000' the discrepancies only start to appear within 10 nm at 20 000 within 20 nm etc even then they are very small and hardly worth worrying about e g at 35 000' 35 nm ground distance = 35 6 nm dme distance and 10 nm gnd dist = 12 nm dme dist exemple 436 A the ground distance and centre the dme-station.

Question 200-36 : An aircraft has a magnetic heading of 290°and is on vor radial 280° which value has to be selected on the obs to get a to indication and the cdi centred ?

100°

Refer to figure .to start with the heading is given in the question as a 'red herring' it is not a useful piece of information the cdi does not have a heading input so is not affected by any heading changes .after discounting the heading we can now draw out the scenario that we are in our aircraft is on radial 280 from the vor and the question asks us what we need to set the obs omni bearing selector to in order to get a centred indication and a 'to' indicator that means that we want to know what track to fly to go directly towards the beacon in this case being on radial 280 means that we are 280º from the vor so we would have to fly a track of 100º to the vor exemple 440 100°

Question 200-37 : The bfo selector switch on the adf control panel must be in the 'on' position to enable the pilot to ?

Hear the ident of ndbs using n0n a1a transmissions

Navigational ndbs have an unmodulated carrier wave icao classification n0n .station identification is transmitted at roughly ten second intervals .older systems interrupt the carrier wave keying to send an unmodulated but also inaudible morse code ident classified as a1a .user will have also erratic indications while the signal is interrupted in this type of beacon .to make the unmodulated parts of the a1a signal audible adf equipment incorporates a beat frequency oscillator bf0 that produces a signal slightly removed from the received frequency that is then mixed with it .the mixing of the two frequencies produces an audible beat frequency tahat is the difference of the two .summary selecting the bfo on makes the n0n carrier wave audible and allows the a1a type of ident to be heard .note bfo is not needed for an a2a signal which is already modulated to an audible frequency exemple 444 Hear the ident of ndbs using n0n a1a transmissions.

Question 200-38 : An ndb is on a relative bearing of 316° from an aircraft given .. . . compass heading . 270°. . . at aircraft deviation . 2°w. . . at aircraft variation . 30°e. . . at station variation . 28°e. . ..calculate the true bearing of the ndb from the aircraft ?

254°

Initially we can use the compass heading and relative bearing to calculate the compass bearing to the ndb .to do this we just add the two numbers together .270º + 316º = 586º too large so take 360º away = 226º compass bearing.then to use cdmvt to calculate the true bearing to the ndb off this remember to use the variation at the aircraft as that is where the direction is measured for ndb/adf operations .. . . compass. deviation. magnetic. variation. true. . . 226º. 2ºw . 224º. 30ºe + . 254º. . ......so the true bearing from the aircraft to the ndb is 254º exemple 448 254°

Question 200-39 : Given the following information what relative bearing will be shown on the rbi in order to maintain an outbound course of 257° m from overhead the ndb w/v 230° t /20 kt . variation 6°e . tas 80 kt ?

188°

Refer to figure the aircraft needs to maintain a magnetic course of 257º away from the station a left wind 230ºt/20 kt is being experienced therefore a wind correction angle must be applied to the left in order to maintain the desired track .to calculate the wca we must either convert the magnetic track into true or the wind into magnetic the question gives a magnetic variation of 6ºe => variation east magnetic least the wind direction is therefore 230º 6º = 224º calculate the wind correction angle using the flight computer set wind direction under 'true index' 224º set the centre point over tas 80 kt and mark wind velocity up from centre point over 100 kt set the course under 'true index' 257º wind correction angle reads between centre line and wind velocity mark => wca of approx 8ºwe can now calculate the magnetic heading = 257º 8º = 249ºmagnetic bearing = relative bearing + magnetic headingthe magnetic bearing to the station is the reciprocal of the magnetic bearing from the station 257º 180º = 077ºmagnetic bearing = relative bearing + magnetic heading .077º = rb + 249º .rb = 077º 249º .rb = 172º + 360º = 188º exemple 452 188°

Question 200-40 : On the qdr of 075° in the vicinity of the station with a magnetic heading of 295° the relative bearing on the adf indicator is ?

320°

Refer to figure . qdm = magnetic bearing from the aircraft to the station . qdr = magnetic bearing from the station to the aircraft radial if our qdr radial is 075º then our qdm is the reciprocal of that which is 255º then you can think of it one of two ways our qdm of 255º is 40º to the left of our current heading 295º and the relative bearing that is 40º left of our nose is 320º . . you could also use the formula . mh + rb = qdm mh = magnetic heading rb = relative bearing qdm as described above rearranged to make . rb = qdm mh = 255º 295º = 40º which is too low so add 360º = 320º relative bearing exemple 456 320°


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