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Question 203-1 : Ils approaches are divided into facility performance categories which of the following statements relates to facility performance category ii ? [ Exam pilot ]

Guidance is provided from the coverage limit to the point at which the localiser course line intersects the ils glide path at a height of 15 m 50ft or less above the horizontal plane containing the threshold

Refer to figure .learning objective 062 02 05 04 01 explain that ils approaches are divided into facility performance categories defined in icao annex 10 ..icao annex 10 sets out facility performance categories in order to set out the requirements for cat i ii and iii approaches there are therefore facility performance category i ii and iii instrument landing systems .the differences between the three facility performance categories are numerous everything from the accuracy down to the monitoring is defined for all three facility performance categories with many more variables in between in the end that means that they can provide increasingly good guidance to aircraft as the category goes up and the associated minima get lower as you can see in the annex above taken directly from icao annex 10 facility performance category i can give guidance down to a height of 100 ft or less category ii down to 50 ft or less and category iii down to the runway with the aid of ancillary equipment .it is important to note that the facility performance categories do not use the same altitudes at the ils categories we use in normal operations a facility performance category i ils system is capable of providing information for a cat i ils as it gives useful information down to 100ft which is lower than the lowest minimums of a cat i ils at 200ft this gives some safety margin in the system which is always useful at such extremely low heights exemple 303 Guidance is provided from the coverage limit to the point at which the localiser course line intersects the ils glide path at a height of 15 m (50ft) or less above the horizontal plane containing the threshold.

Question 203-2 : What causes the dip error in an adf ?

The tilted antenna whilst banking the aircraft

Learning objective 062 02 02 05 03 explain that the bank angle of the aircraft causes a dip error with the way that an adf antenna picks up the direction of the incoming signal there can be quite a significant error brought into the reading simply by banking the aircraft by doing this the antenna is no longer level so is now detecting a downwards component of the signal which effects the reading in a similar way to tilting a compass this is called 'dip error' when tracking ndbs in real life dip error is actually quite large and means that the adf needle far less accurate whilst in the turn it is also a very difficult eerror to correct for accurately exemple 307 The tilted antenna whilst banking the aircraft.

Question 203-3 : Which frequency band do dmes operate within ?

Ultra high frequency uhf 300 mhz to 3000 mhz

Refer to figure . learning objective 062 02 04 01 01 state that dme operates in the uhf band each frequency band is effectively a logarithmic band which begins at one frequency value and ends at the frequency value 10x higher they all begin with the number 3 and are of different orders of magnitude dmes operate within uhf ultra high frequency which is the band above the well known vhf frequency band therefore a good way of remembering the frequency bands is having vhf as a starter band and we can say that a well known vhf frequency of 121 5 mhz is between 30 and 300 mhz so therefore we can create the bands above and below that and so on there is an acronym to remember the order using the first letters 'very lovely maidens have very useful sewing equipment' exemple 311 Ultra high frequency (uhf): 300 mhz to 3000 mhz

Question 203-4 : Given the following information what is the true bearing from the ndb to the aircraft compass heading 348º . adf indication relative bearing indicator 317º . deviation 2º . variation 22ºw . the convergence is negligible ?

101º t

Refer to figure .first we must calculate our true heading then we can use our relative bearing to calculate our true bearing from the ndb sometimes called a qte .to calculate our true heading we can use the saying 'cadbury's dairy milk very tasty' which is popular within british aviation schools also an option is 'tv makes dumb children' which is a reversal of the other saying there is a universal method which can be used that applies to both directions compass deviation magnetic variation true .to get our compass heading into a magnetic heading we apply the deviation using the rhyme .. deviation west compass best. deviation east compass least..we must also know that a positive value is easterly and a negative value is westerly it can be given in either format so in this case our compass heading is 2º more than our magnetic heading so our magnetic heading is 348º 2º = 346º .now to get true heading we apply variation to our magnetic value using the rhyme .. variation west magnetic best. variation east magnetic least.we now know that our magnetic heading is 22º more than our true heading so true heading = 346º 22º = 324º ..with this in mind we can apply the relative bearing to our true heading which is simply a case of adding the two together .true heading + relative bearing = 324º + 317º = 641º which isn't possible so subtract 360º > 281º.281º is therefore the true bearing from the aircraft to the ndb we want to find the opposite direction to this so we shall simply add or subtract 180º giving us 101º true bearing from the ndb to the aircraft .note even though this does look like a gnav or fpl question the feedback shows that it has been asked in rnav and the rnav learning objectives include specific references to the topics 062 02 02 02 02 062 02 02 02 04 and 062 02 02 02 05 everything required for this question is in the rnav syllabus exemple 315 101º (t)

Question 203-5 : An aircraft equipped with a vhf radio is flying within radio range of two or more ground direction finding stations which aircraft parameter can be determined in this scenario the aircraft's ?

Position

Learning objective 062 02 01 02 03 explain that by using more than one ground station the position of an aircraft can be determined and transmitted to the pilot ..vdf vhf direction finding is a method of measuring the direction from which a vhf signal came it has been used for many decades now and is particularly useful as the transmitting aircraft only needs a standard vhf radio to ask for a vdf bearing from a suitably equipped atsu this can give them .. qdm magnetic bearing from the aircraft to the station . qdr magnetic bearing from the station to the aircraft . quj true bearing from the aircraft to the station . qte true bearing from the station to the aircraft ..with this information the pilots can plot the location of their aircraft on a chart by drawing a true radial qte outbound from each station that was used 2 stations and therefore 2 lines can be enough to calculate the position of an aircraft by finding the point at which they intercept this is a process known as triangulation it is important to get a large angle at the point of interception as the larger the angle optimum 90º the better the precision of the fix more than 2 vdf stations can also be used to get a more accurate fix .distress and diversion 121 5 mhz have access to an auto triangulation feature which gives them an immediate readout of the position of any calling aircraft due to the reception of its transmission at multiple different locations with vdf capability .position is the only thing that can be gained from vhf direction finding though so it is limited in that sense but is very useful in the sense that only a vhf radio is required in the aircraft exemple 319 Position

Question 203-6 : A cat i ils with a decision height of 240 ft is what type of approach ?

Type b 3d approach

Icao annex 6 part ii . 2 2 2 2 2 instrument approach operations shall be classified based on the designed lowest operating minima below which an approach operation shall only be continued with the required visual reference as follows a type a a minimum descent height or decision height at or above 75 m 250 ft andb type b a decision height below 75 m 250 ft type b instrument approach operations are categorized as 1 category i cat i a decision height not lower than 60 m 200 ft and with either a visibility not less than 800 m or a runway visual range not less than 550 m 2 category ii cat ii a decision height lower than 60 m 200 ft but not lower than 30 m 100 ft and a runway visual range not less than 300 m . 3 category iii cat iii a decision height lower than 30 m 100 ft or no decision height and a runway visual range less than 300 m or no runway visual range limitations this is new from 2018 and categorises instrument approaches into type a or type b depending on their decision height or minimum descent height being above or below 250ft as the approach in question is an ils which has both horizontal and vertical guidance it is therefore a 3 dimensional 3d approach and its decision height is below 250 ft so it is 'type b' note this question does cross over quite heavily with air law but feedback shows that it is being asked in rnav exams exemple 323 Type b, 3d approach

Question 203-7 : Which of the following statements is true ?

With an a2a modulated wave you can hear the wave in adf mode

Refer to figures . the first annex above contains the 4 learning objectives which relate to this question 2 different types of ndb exist and they are categorised by their radio wave modulation the earlier type of ndb is called n0n a1a and the newer type is n0n a2a the only difference between the two is that a1a signals can not be identified unless the bfo beat frequency oscillator mode is used whereas a2a signals can be identified aurally in standard adf mode as well the reasons behind this are slightly too complex for the syllabus and most modern adf panels use the bfo mode automatically when required anyway exemple 327 With an a2a modulated wave you can hear the wave in adf mode.

Question 203-8 : An aircraft is equipped with a dme receiver that can provide a read out of ground speed it is climbing on a heading of 270° t and is crossing the 330 radial from a vor/dme station the ground speed calculated by the dme computer is ?

Less than the actual ground speed because the change in slant range is smaller than the change in ground distance

Refer to figure . some dme receivers have a setting that will read out the aircraft's groundspeed when heading towards or away from the station as well as an estimate of the time to the station this is calculated by the dme receiver using the rate of change of the detected distance from the station this means that flying anywhere other than directly to/from the station causes an unusable read out as is the case in this question where we are crossing the radials another thing to consider is that dme systems calculate slant range from the aircraft to the station so the dme groundspeed calculations are more accurate when this slant range closely resembles ground distance so when at low altitude and far away from the dme within line of sight of course in this question our aircraft is crossing the 330 radial and the slant distance is increasing a small amount but by much less than our groundspeed therefore the groundspeed read out on our dme will be lower than our actual groundspeed exemple 331 Less than the actual ground speed because the change in slant range is smaller than the change in ground distance.

Question 203-9 : A pilot has selected the appropriate ils frequency for the approach that they are currently established on which of the following scenarios would cause a warning flag to appear on both the localiser loc and giide path gp indications ?

Absence of both carrier waves

Learning objective 062 02 05 02 05 describe the circumstances in which warning flags will appear for both the loc and the gp absence of the carrier frequency absence of the modulation simultaneously the percentage modulation of the navigation signal reduced to 0 ..when on the approach the sudden appearanc of both flags must mean a fault of some kind not just being out of range so this must be down to one of the faults listed in the learning objective above the easiest fault to remember is correct in this case as the sudden absence of a carrier wave is certainly going to remove loc and gp indications and will therefore show warning flags .the other answers are wrong because .. the difference in depth of modulation ddm is the way an ils tells you where you are in relation to the localiser centreline or the glide path and a ddm of zero means being exactly on the loc or gp . 'excessive loc or gp deviations' is vague but even when at more than full scale deflection but within the coverage area the indicators still show the direction we are off track/glidepath . loss of ident transmission would not show flags on its own but there might be a common error which causes both flags to show and the ident to stop transmitting such as a total power loss etc exemple 335 Absence of both carrier waves.

Question 203-10 : To avoid the inaccuracies that may be caused by coastal refraction the pilot should attempt to take adf bearings when… ?

The aircraft is on the perpendicular to the coast which runs through the ndb

Refer to figure . learning objective 062 02 02 04 01 explain ‘coastal refraction’ as a radio wave travelling over land crosses the coast the wave speeds up over water and the wave front bends coastal refraction affects ndb/adf equipment due to the type of carrier wave that ndbs transmit they transmit between 190 and 1750 khz which is partly in the lf band and partly in the mf band these waves travel as surface waves which are massively affected by the surface they are travelling over water is much smoother to travel over than land so the waves are able to travel a bit faster this creates a change in speed when ndb carrier waves go from land to sea which can cause a process called refraction meaning that the beam bends away from the perpendicular called the normal and therefore creates the image shown in the annex this means that the carrier wave arrives at our aircraft from a slightly different direction than it should and our adf therefore reads incorrectly the best way to stop this is to place ndbs very close to the coast thereby reducing the error or to take adf readings when the signal crosses the coast at a right angle perpendicular the closer to the perpendicular the less refraction will occur and so is less affected by the coastal effect exemple 339 The aircraft is on the perpendicular to the coast which runs through the ndb.

Question 203-11 : Which of the following options can be used for entry into a holding pattern based on a vor/dme fix ?

The dme arc defining the fix

Note the feedback strongly suggests that this is a question asked in previous rnav exams even though there are no learning objectives within the rnav syllabus that pertain to it .it is more of an air law question and even then it is on the edge of learning objective 010 06 05 01 10 .the good thing is that it is a very distinctive question that will be easy to remember for the exam ..refer to figures .there are a few different places a holding pattern can be constructed over ndbs vors over a vor/dme fix or over an rnav waypoint not a conventional nav aid .the most complex of those is certainly the vor/dme fix .technically a hold can be placed on 2 intersecting radials but they are extremely rare .in the 1st annex above stockholm arlanda overview of all holding patterns there are all the different types of holds shown .starting from the top you can see hammar hmr vor and there is a hold there with the inbound course of 191° and left turns and 1 5 minute legs usually 1 min legs are used but this is a higher altitude hold .below this is the erken erk ndb hold based directly on the ndb .to the far left of the chart is the tinka hold which is simply based on an rnav/rnp waypoint .the furthest south holding pattern nilug is a hybrid it is an rnav waypoint but with a vor/dme fix given so that it can be flown using conventional nav aids .this is what the question is asking about .there are 3 more of these on the chart eltok balvi and xilan ..firstly note that all these vor/dme holds all have inbound courses directly towards the vor this is so the inbound course can always be tracked which is a key requirement of any holding pattern technically they can also track directly away from the vor but i have never seen one published .in the case of the nilug hold the pilot will fly inbound on the 007° to course radial 187 towards tebby teb vor until reaching a dme distance of 44 2 nm then begin the right hand turn and do the rest of the procedure using timings which is very normal until established on the inbound course again where tracking resumes until 44 2d etc .they are easy enough to fly if a little inaccurate due to being so far from the vor the difficulty arrives due to the fact that they can only be joined from particular directions .as can be seen in the annex above they can only be joined using conventional nav aids from .a the vor radial.b the dme arc where specified or.c the entry radial to a vor/dme fix at the end of the outbound leg as published .by far the most common way and easiest is by the vor radial but that is not one of the available options so we have to say the dme arc defining the fix in this case 44 2 nm .see the 2nd annex for a view of the dme arc for this example exemple 343 The dme arc defining the fix.

Question 203-12 : What causes 'mountain effect' and what type of navigational aid does it affect ?

It is caused by diffraction and affects ndbs

Learning objective 062 02 02 05 01 ndb section describe diffraction of radio waves in mountainous terrain mountain effect .because ndbs produce lf and mf radio waves which travel primarily as surface ground waves for the purposes of directional navigation as is required for ndbs the ground that is being travelled over matters a lot water is flat for instance so surface waves travel over water faster and much further than a similar strength wave travelling over rolling hills built up areas and worst mountainous terrain basically the more obstacles and rougher the terrain the worse the ndb signals travel .this is most prominent in mountainous terrain as the radio waves try and follow the contours of the ground which means going over the peaks and into the valleys the largest problem with this is a phenomenon known as diffraction where the wave gets scattered slightly as it crests each mountain and tries to go down the other side .reflection of the waves also could be an issue but does not affect ndb directions received by aircraft as much as the relative diffraction of mountains exemple 347 It is caused by diffraction and affects ndbs.

Question 203-13 : You are established on an ils approach at 4 nm on the dme and get some signal interference what could be the reason for this ?

Multipath interference from reflections off objects within the published coverage area

Learning objective 062 02 05 04 08 explain that multipath interference is caused by reflections from objects within the ils coverage area .we can be sure that the aircraft is within the coverage area in this question as it is fully established on the ils approach at 4 nm it is most likely to be descending on the glide path as well as on the localiser this leaves only one answer available as none of the other options happens when within the correct coverage area of the ils .reflections of the ils signals off objects can hit the aircraft at certain stages of the approach altering the difference in depth of modulation between the 90 hz and the 150 hz lobes and can cause a false movement of the ils needles which in turn can affect the autopilot if one is engaged exemple 351 Multipath interference from reflections off objects within the published coverage area.

Question 203-14 : You are flying on radial 227° inbound to a vor the wind is from 270° and the wind correction angle is 3° the magnetic variation is 10°w the obs should be set to 1 and magnetic heading should be 2 ?

1 047° 2 044°

If we are flying inbound on the 227° radial then our track has to be the opposite 047° 047° is therefore what we also want to set as our obs course as we want the needle to indicate in the correct sense as we track to the vor the wind in this scenario is coming from 270° it does not matter whether true or magnetic which is a partial tailwind blowing across from the left this means that we have to turn left by our wind correction angle 3° to track 047° this gives us a heading of 044° to fly all our bearings and tracks are in magnetic as this is what is used by vors and the wind does not matter as 10° different would still make the wind a tailwind/crosswind from the left exemple 355 (1) 047°; (2) 044°

Question 203-15 : A doppler vor provides usable signals up to what distance from the station and is intended for which type of traffic ?

Up to 200 nm from dvor for en route ifr traffic

Learning objective 062 02 03 01 04 state that the following types of vor are in operation conventional vor cvor a first generation vor station emitting signals by means of a rotating antenna doppler vor dvor a second generation vor station emitting signals by means of a combination of fixed antennas utilising the doppler principle en route vor for use by ifr traffic terminal vor tvor a station with a shorter range used as part of the approach and departure structure at major aerodromes test vor vot a vor station emitting a signal to test vor indicators in an aircraft .as stated in the learning objective above dvors are powerful enough to be used by en route ifr aircraft for reliable navigation by looking in the enr section of an aip the useful ranges of the vors can be seen and the maximum is 200 nm distance and 50 000 ft altitude exemple 359 Up to 200 nm from dvor for en-route ifr traffic.

Question 203-16 : When tuned in to an ndb when is dip error most likely to occur ?

When turning towards the ndb

Learning objective 062 02 02 05 03 explain that the bank angle of the aircraft causes a dip error ..dip error is an inaccurate reading of the bearing information when the aircraft is banked this is because the adf system that receives and interprets ndb signals was designed to work when in horizontal flight when a turn is initiated the indicated bearing is modified the needle will cause an error towards the direction of whichever wing is banked down exemple 363 When turning towards the ndb.

Question 203-17 : When holding at an ndb you are approaching the beacon on the inbound leg how will you know when to initiate the turn ?

The head of the needle will be pointing to the fix and the needle will turn 180° when passed it

Refer to figure .a holding pattern requires an aircraft to fly towards the holding fix on a certain 'inbound' track and when the aircraft reaches the fix vor ndb or a vor/dme fix the pilots should begin a 180º turn right is standard but left turns can be used upon the end of this turn or passing abeam the beacon the pilot will then fly a timed leg on the opposite track plus any wind correction to the inbound leg now called the outbound leg then turn back onto the inbound leg to start the process again this forms the familiar racetrack pattern an ndb simply produces a signal of particular frequency and the adf receiver in our aircraft picks this up and tells us from where it came this is very simple and means we can follow an adf needle all the way to the beacon when it will then become very sensitive and go from pointing ahead of the aircraft to pointing behind it as per the location of the ndb this is different from a vor which we would track inbound via a cdi course deviation indicator which flicks from to to from upon passing the beacon and also has a cone of confusion exemple 367 The head of the needle will be pointing to the fix and the needle will turn 180° when passed it.

Question 203-18 : You are flying the inbound course of an ndb holding pattern in an area of local thunderstorm activity what might the adf indicate ?

The needle will point towards the thunderstorm

Note we require further feedback about this question from the exam .in particular we belive two of the answers are partly correct .the needle would point towards the thunderstorm very often but would also act erratically however it shouldn't matter whether it is night or day the night effect is to do with other ndbs which are usually out of range during the day the effect should be the same which makes us want to discount that erratic option ..learning objective 062 02 02 05 02 state that static radiation energy from a cumulonimbus cloud may interfere with the radio wave and influence the adf bearing indication ..thunderstorms can have very powerful discharges of static electricity across much of the electromagnetic spectrum including in low frequency lf and medium frequency mf .these discharges cause the most severe errors in adf receivers .a static discharge in a cumulonimbus cloud cb can be heard as a loud crackle on the audio and the needle will move rapidly to the source of the cb .if there are several active thunderstorms in the area the needle might point to them for a longer period .as thunderstorms are incredibly powerful the electromagnetic waves they give off can easily overpower that of an ndb especially if it is only a low power locator beacon exemple 371 The needle will point towards the thunderstorm.

Question 203-19 : During an ils approach with 3º glide slope you initiate a go around when the dme reads 1 nm from the threshold and decreasing you are at a height of 1 200 ft over the runway elevation and you notice that the glidepath indicator is showing no deflection and no flags as if you were correctly on the ?

The aircraft is flying within the side lobes of the glide path signal

The glidepath of an ils works similar to the localizer except the glidepath operates in the ultra high frequency uhf instead of the very high frequency vhf band .as seen in the figure there are 2 lobes on the glidepath .one lobe at 90 hz which indicates that the aircraft is above the glidepath .and one lobe at 150 hz which indicates that the aircraft is below the glidepath .the centre is typically set to a 3° glidepath this is not a perfect system and the glidepath can suffer from the presence of false glidepaths above the correct one .these are due to both the weak sidelobes of the original 150 hz and 90 hz lobes which are created and intensified by the reflection of the lower signals off the ground or nearby obstacles .this is the similar to multipath interference of the localiser but is more easy to predict .these false glidepaths are reverse sensing see 2nd annex above and usually exist at odd multiples of the original glidepath and are the reason why we procedurally will intercept the glidepath from below to avoid encountering a false glidepath note we have had updated feedback in the comments on this question but could still use more to fine tune the wording and check the other options exemple 375 The aircraft is flying within the side lobes of the glide path signal.

Question 203-20 : You are flying across northern canada on airway nca whiskey you wish to cross check the irs computed position by taking a bearing from a nearby vor you tune into the churchill vor and find you are on the 190° radial what is the bearing to plot on a chart if the variation at the vor is 2°w and the ?

188°

Refer to figure .to cross check our position using a chart we must find the true bearing from a known position to our aircraft in this case the known position is the churchill vor and we are on radial 190° radials from vors are in magnetic so we know the magnetic bearing from the vor to the aircraft is 190° m and also that we should use the variation at the vor to calculate our true bearing an easy way to remember this is that v is for vor and also for variation so use the variation at the vor there are many ways to turn this into a true bearing one of which is the rhyme variation east magnetic least .variation west magnetic best therefore our magnetic bearing of 190° is greater than our true bearing by the amount of 2° so the true bearing to plot from the vor on the chart would be 188° t note 1 another piece of information would still be required to compute the position of the aircraft such as another vor bearing or a dme readout .note 2 in canada airspace northern domestic airspace nda is the area of compass unreliability within which runways and navaids are oriented to true north however churchill vor is not included in nda airspace as they would have to specify this in the question .note 3 there is another extremely similar question with radial 300° so do not get this mixed up with that one or vice versa exemple 379 188°

Question 203-21 : What criteria must be met to be considered established on an ndb approch ?

The bearing pointer must be within 5º of the required course

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 .ndb's can be used to provide a non precision approach to an airport a pilot can make sure to be aligned with the correct approach path by maintaining the same qdm with the adf and can manage vertical guidance using their altimeter with a minimum descent height/altitude .in terms of lateral errors permitted flying an ndb approach you must maintain a qdm/qdr that is ± 5° of the designated approach path this is also the range in which an aircraft can be considered established on the approach ..as the process of flying ndb approaches varies depending on the cockpit hardware this question could potentially cause some confusion let's look at each option .. the relative bearing must be less than 5º . . this is incorrect as the relative bearing direction of the adf pointer relative to the aircraft heading will vary due to the wind correction angle an aircraft could be perfectly flying an inbound course of 270º but with a 10º right wind correction so heading 280º the relative bearing would be 350º 10º left of the nose but the aircraft would be established . . . the bearing pointer must be within 5º of the required course . . this is true as the bearing pointer indicates the qdm when using an rmi or converting a fixed card adf and that must be within 5º of the correct inbound course for the approach as long as that criteria is satisfied the aircraft is considered established the wording could be better to include all versions of aircraft hardware but this is correct in essence and far more correct than the other options . . . the wind correction angle must be less than 5º . . the wind correction angle does not matter as long as the aircraft is within 5º of the required qdm it is established . . . variation due to reflections from terrain may not exceed 5º . . variations due to terrain reflections can affect ndb signals but should not do so too much on ndb approaches as this should be flight tested etc nonetheless ndb approaches have terrible accuracy and many errors hence the high minimums as we cannot determine the errors at any one time we can only use the instrument readout that we have so a high error does not mean that we are not established exemple 383 The bearing pointer must be within 5º of the required course.

Question 203-22 : On a back beam ils approach with the inbound course from the chart set on the hsi what does a pilot need to keep in mind ?

The cdi will be reverse sensing with no glide path information

Refer to figures . an ils localiser uses two lobes of differently modulated signals one is modulated at 150 hz and the other at 90 hz the ils receiver on an aircraft interprets the amount of each signal as an indication of how far the aircraft is from the centre of the localiser and on which side this indication is shown directly on the display the obs omni bearing selector which is used for vor radial tracking does not have an impact on the displayed ils readings the course deviation indicator cdi will just show 'fly left' or 'fly right' according to the signals it receives a horizontal situation indicator hsi has a simple cdi in the middle of the slaved gyro compass which can be turned to face any direction on the gyro compass but when receiving ils signals will only show exactly what it receives fly left or fly right the direction of the cdi does not affect the cdi localiser indications just how we view them the localiser of an ils approach can produce a secondary 'back beam' which goes exactly the opposite direction to the original localiser this will allow for an approach to be performed using this 'back beam' but it is limited by the fact that it will be reverse sensing in localiser indications and has no glide path signal so is a non precision approach only if the back beam is not required it is often suppressed to avoid any confusion see the second annex above an approach chart for a back course approach the charted approach course is 016º but the standard ils front course approach is to the opposite runway and is 196º inbound if we related this chart to our question we are going to fly 016º inbound course using the loc back beam and have our hsi course set to 016º as we are about to discuss this is actually not the best course to set when using a ils back course the usual signal lobes are reversed so the cdi in the centre of the hsi will be reverse sensing this is the scenario of this question and what we see on the left hand side of the first annex above the hsi is reverse sensing with the 'back course' direction set usually however we actually set the direction of the ils front course right hand side of the annex which reverses the direction again and gives us correctly sensing indications this has not been done in this question exemple 387 The cdi will be reverse sensing with no glide path information.

Question 203-23 : How can ndbs be used for navigation near the destination aerodrome ?

As a locator beacon to start the final approach segment

Learning objective 062 02 02 01 07 define a ‘locator beacon’ an lf/mf ndb used as an aid to final approach usually with a range of 10 25 nm .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 are split into two use categories en route for long range navigation and locator beacons for terminal procedures .as specified in the lo above locator beacons are low powered ndbs and have short ranges of 10 25 nm they are often used as beacons denoting the approach holding pattern or the final approach fix they may be co located with a marker beacon the outer marker usually but ndbs are different from marker beacons which people do occasionally get mixed up exemple 391 As a locator beacon to start the final approach segment.

Question 203-24 : You are flying a dme arc as part of a procedure when you begin a descent/climb what will happen to the dme groundspeed indication ?

It will not change because the slant range is the same

Refer to figures .the dme cockpit indication can show a few different indications the frequency distance sometimes identifier and sometimes groundspeed this is not a true groundspeed indication though as the only thing it can go off is the rate of increase/decrease of dme range .therefore if the aircraft is flying directly towards or away from the dme the groundspeed indication will be correct* but if flying at any other angles it will be wrong and always indicate less than the actual groundspeed *a dme actually measures slant range between the aircraft and the ground station so the groundspeed indication is slightly off due to this and is more accurate when the slant is shallower so at low altitudes or further away from the station in a dme arc then which is a procedure flown at the same slant range from the dme annex above the groundspeed should read 0 kts as the range is not changing at all .in the descent climb the aircraft's slant range would begin to decrease increase so the aircraft ends up flying slightly further away from closer to the dme in terms of ground distance and maintaining an indicated dme groundspeed of 0 kts exemple 395 It will not change because the slant range is the same.

Question 203-25 : Which of the following frequencies may be allocated to a vor station 1 frequency 112 3 mhz . 2 frequency 117 9 mhz . 3 frequency 118 9 mhz ?

1 and 2

The band normally used for aeronautical mobile service ams voice communication is the very high frequency vhf band and is defined between 118 000 and 136 975 mhz the lower part of the spectrum from 108 to 117 975 mhz is reserved for navigational aids such as vor beacons automatic terminal information service atis precision approach systems such as ils or laas frequency band frequencies wave band wave length vlf very low frequency 3 30 khz very long 100 10 km lf low frequency 30 300 khz long 10 1 km mf medium frequency 300 3000 khz medium 1 km 100 m hf high frequency 3 30 mhz short 100 10 m vhf very high frequency 30 300 mhz short 10 1 m uhf ultra high frequency 300 3000 mhz ultra short 1 m 10 cm shf super high frequency 3 30 ghz 3000 30000 mhz super short 10 1 cm ehf extremely high frequency 30 300 ghz extremely short 1 cm 1 mm exemple 399 1 and 2.

Question 203-26 : Multipath errors are caused by… ?

Objects within the ils coverage area

Refer to figure .062 02 05 04 08 explain that multipath interference is caused by reflections from objects within the ils coverage area the 2 ils localiser lobes and the 2 glideslope lobes can cover a wide area especially when further from the airfield this is known as the ils coverage area any obstacles within this area can reflect the ils signals potentially sending a different amount of one frequency to your ils receiver than it should this is called multipath interference and can cause an ils display to show untrue fluctuations in both the horizontal and the vertical this can be especially dangerous when connected to autopilot which could pitch or roll excessively due to the ils fluctuations exemple 403 Objects within the ils coverage area.

Question 203-27 : An aeroplane is on approach with nav 1 tuned to the ils frequency and nav 2 tuned to the vor frequency which also provides an approach to the same runway when the cdi of nav 2 reaches exactly full scale deflection the nav 1 cdi will show ?

Full scale deflection

Refer to figure .note this is effectively the reverse way round to question 621370 we have received limited feedback about this question currently so please let us know if you see it in the exam thank you ..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 4 times more accurate .therefore on a standard 5 dot cdi vors have a deviation indicated by 2 degrees per dot so full scale deflection is 10° 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 5° deviation from the localiser centreline .therefore in this scenario where we are on exactly full scale vor deflection we are 10° off the correct inbound course which is more than full scale deflection on the localiser cdi which will show as full scale deflection as we are still within the ils coverage area due to the fact that we are on approach exemple 407 Full scale deflection.

Question 203-28 : As an aeroplane is approaching the runway while taxiing for departure the flight crew observes two sets of yellow lines drawn across the taxiway one line further away from the runway has a sign stating 's2 cat ii/iii ' and the line closer to the runway has a sign stating 'si' why is there a ?

The landing minima for cat ii and ill operations are lower and therefore require greater precision and an aircraft waiting too close to the landing runway may affect the quality of the ils signals

Refer to figure . learning objective 062 02 05 05 02 define the ‘ils sensitive area’ an area extending beyond the ils critical area where the parking or movement of vehicles including aircraft is controlled to prevent the possibility of unacceptable interference to the ils signal during ils operations cat ii and cat iii operations require high accuracy standards the aircraft flying cat ii or cat iii approaches follow the ils loc and gp signals and based on these signals they are flown down to a low height above the touchdown or even all the way to the touchdown depending on the category since on precision approaches cat ii and iii the system is capable of bringing the aircraft too low or even on touchdown measures need to be taken to ensure that their signals will not be affected by interference of any kind ils localizer and glide slope signals are radio waves and can therefore be affected by interference the most common type of interference for ils signals are multi path interference and beam bends these can happen for a multitude of reasons but primarily due to the reflections of the radio waves off buildings terrain vehicles etc an aircraft waiting too close to the runway may affect the quality of the ils signals making it harder for the landing aircraft to maintain its course and height accurately therefore a separate holding position is required to ensure that the signals are not affected by other aircraft movements this is the reason that during lvos low visibility operations cat ii/iii approaches at many airports aircraft are required to use different holding points further from the runway in order to remain outside the ils sensitive area also known as the lsa localiser sensitive area exemple 411 The landing minima for cat ii and ill operations are lower and therefore require greater precision, and an aircraft waiting too close to the landing runway may affect the quality of the ils signals.

Question 203-29 : At night the ionosphere undergoes changes in ionisation density leading to fluctuations in the strength of received signals in the lf/mf frequency band this phenomenon is commonly referred to as ?

Fading caused by the received ground wave and sky wave going out of phase

Refer to figure . night effect . the principal propagation method of ndbs is the ground wave however it is possible for weak sky waves to be returned at night when the ionosphere is less dense and attenuation is least during the day the d layer of the ionosphere absorbs signals in the lf and mf bands at night the d layer disappears allowing the sky wave to interfere with the surface wave this interference occurs due to the different paths taken by the sky wave and surface wave as well as the induction of currents in the horizontal elements of the loop aerial the contamination effect which is observed as fading of the audio signal and the needle 'hunting' is most pronounced around dawn and dusk when the ionosphere is transitioning at shorter distances 30 to 80 miles the sky waves combine with the ground wave signal without any dead space since the sky waves travel a different path they have a different phase compared to the ground wave as a result the aerial null signal is suppressed or displaced in a random manner leading to wandering of the needle on the rmi or rbi this effect is called fading and is most variable during twilight at dawn and dusk exemple 415 Fading, caused by the received ground wave and sky wave going out of phase.

Question 203-30 : A tacan tactical air navigation radio aid is a uhf military system that may ?

Be used for range information by civil aircraft

Learning objective 062 02 04 01 08 state that military uhf tactical air navigation aid tacan stations may be used for dme information .tacan tactical air navigation systems are military uhf tactical radio aids that can be used by military aircraft with the correct receiver fitted tacans provide military aircraft with magnetic bearing radial and range dme distance information from the station tacan function is similar to vor/dme function but for military aircraft receivers only .if a civil aircraft is tuned to a tacan frequency the aircraft will receive range dme distance information only magnetic bearing information radial will not be available exemple 419 Be used for range information by civil aircraft.

Question 203-31 : When mode c is selected on the aircraft ssr transponder the additional information transmitted is ?

Pressure altitude based on 1013 25 hpa

.mode c sends the aircraft's pressure altitude provided by the altitude encoder exemple 423 Pressure-altitude based on 1013.25 hpa.

Question 203-32 : The ground secondary surveillance radar ssr equipment incorporates a transmitter and receiver respectively operating in the following frequencies ?

Transmitter 1030 mhz .receiver 1090 mhz

.secondary surveillance radar ssr is a radar system used in air traffic control atc which not only detects and measures the position of aircraft but also requests additional information from the aircraft itself such as its identity and altitude .the interrogation pulses are at one frequency 1030 mhz and the reply pulses are at a different frequency 1090 mhz .the target aircraft's transponder replies to signals from an interrogator by transmitting a coded reply signal containing the requested information exemple 427 Transmitter: 1030 mhz xsxreceiver: 1090 mhz

Question 203-33 : Assuming sufficient transmission power the maximum range of a ground radar with a pulse repetition frequency of 450 pulses per second is . given velocity of light is 300 000 km/second ?

333 km

.maximum theoretical range = velocity of light / 2 x pulse repetition frequency .maximum range = 300000 / 2 x 450.maximum theoretical range = 300000 / 900.maximum theoretical range = 333 km exemple 431 333 km.

Question 203-34 : A radio beacon has an operational range of 10 nm .by what factor should the transmitter power be increased in order to achieve an operational range of 20 nm ?

Four

.if you double transmitter power you will increase your range by the square root of 2 1 414 time the range .if you divide 20 nm by square root of 2 = 14 14 nm.and 14 14 by square root of 2 = 10 nm.so you have to increase by a factor of four exemple 435 Four.

Question 203-35 : Airborne weather radar systems use a wavelength of approximately 3 cm in order to ?

Detect the larger water droplets

exemple 439 Detect the larger water droplets.

Question 203-36 : The iso echo facility of an airborne weather radar is provided in order to ?

Detect areas of possible severe turbulence in cloud

.with a monochrome screen it is difficult to distinguish between the severities of turbulent clouds when iso echo is activated a level supplements the automatic gain visual threshold set un weather mode the shap of return on the radar depends upon the gain level of the cloud .the effect is to create a black hole in the cloud by reversing and ampliflying the signal this reversal brings the signal below the automatic gain visual threshold and so no return appears in the middle of the cloud . 2612.turbulence severity is assessable using the above picture . > the hole shows an area of high turbulence . > the outer ring shows the severity of the turbulence gradient within the cloud . the narrower the retaining ring the steeper the gradient . the wider the outer ring the more slack the gradient exemple 443 Detect areas of possible severe turbulence in cloud.

Question 203-37 : In the mapping mode the airborne weather radar utilises a ?

Fan shaped beam effective up to a maximum of 50 nm to 60 nm range

.this answer is not accurate today most radars can have a much longer range than that in the mapping mode up to 120 nm . boeing 737ng navigation displays map mode . 2613 exemple 447 Fan shaped beam effective up to a maximum of 50 nm to 60 nm range.

Question 203-38 : Which of the following cloud types is most readily detected by airborne weather radar ?

Cumulus

exemple 451 Cumulus.

Question 203-39 : Why is a secondary radar display screen free of storm clutter ?

The principle of echo return is not used in secondary radar

exemple 455 The principle of “echo” return is not used in secondary radar.

Question 203-40 : In order to indicate radio failure the aircraft ssr transponder should be selected to code ?

7600

.7600 radio communication failure .7500 unlawful interference with the planned operation of the flight .7700 emergency situation exemple 459 7600.


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