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Question 217-1 : 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 ? [ Preparation civilian ]
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.
Question 217-2 : 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.
Question 217-3 : 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.
Question 217-4 : 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.
Question 217-5 : 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.
Question 217-6 : 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.
Question 217-7 : 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
Question 217-8 : 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.
Question 217-9 : 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.
Question 217-10 : 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 separate ?
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.
Question 217-11 : 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.
Question 217-12 : 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.
Question 217-13 : 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.
Question 217-14 : 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.
Question 217-15 : 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.
Question 217-16 : 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.
Question 217-17 : Airborne weather radar systems use a wavelength of approximately 3 cm in order to ?
Detect the larger water droplets.
Question 217-18 : 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.
Question 217-19 : 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
Question 217-20 : Which of the following cloud types is most readily detected by airborne weather radar ?
Cumulus.
Question 217-21 : Why is a secondary radar display screen free of storm clutter ?
The principle of echo return is not used in secondary radar.
Question 217-22 : 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.
Question 217-23 : In order to indicate unlawful interference with the planned operation of the flight, the aircraft secondary surveillance radar ssr transponder should be selected to ?
7500.
.7600 radio communication failure...7500 unlawful interference with the planned operation of the flight...7700 emergency situation.
Question 217-24 : An apparent increase in the transmitted frequency which is proportional to the transmitter velocity will occur when ?
The transmitter moves towards the receiver.
.because the radio signals travel at a constant speed assuming they are not refracted by the atmosphere , the receiver can calculate exactly how far away it is from the transmitter..speed is most often calculated by the receiver using the doppler effect, which is the process by which the frequency of a signal changes due to the relative motion of the transmitter. frequency is raised when the transmitter moves towards the receiver.
Question 217-25 : A primary radar operates on the principle of ?
Pulse technique.
Question 217-26 : The main factor that limits the range of an ndb is the ?
Transmitted power.
Question 217-27 : The two main design functions of secondary surveillance radar ssr mode s are ?
Air to ground and ground to air data link communications and improved atc aircraft surveillance capability.
Question 217-28 : A frequency of 10 ghz is considered to be the optimum for use in an airborne weather radar system because ?
The larger water droplets will give good echoes.
.a high frequency is used since it gives strong return of echoes from big water droplets and clouds of high water contents, usually thunderstorm movements, but do not reflect the clouds with lower contents of water or fog.
Question 217-29 : Which of the following is a complete list of airborne weather radar antenna stabilisation axes ?
Roll and pitch.
.weather radar antenna in the nose radome of a boeing 757. 2547.you can clearly see the stabilisation system. 2548
Question 217-30 : In an airborne weather radar that has a colour cathode ray tube crt increasing severity of rain and turbulence is generally shown by a change of colour from ?
Green to yellow to red.
. 2614
Question 217-31 : When an aircraft is operating its secondary surveillance radar in mode c an air traffic controller's presentation gives information regarding the aircraft's indicated flight level in increments of ?
100 ft.
.air traffic controller's presentation gives information regarding the aircraft's indicated flight level mode c in increments of 100 ft. 2615.afr1670 air france 1670.038 3800 ft climbing, m15 control sector m15
Question 217-32 : A radar facility transmitting at a pulse recurrence frequency prf of 1200 pulses/second will have a maximum unambiguous range of approximately ?
69 nm.
.maximum range = pulse repetition time/ 2 x 0,162 nm/microsecond..pulse repetition time = 1 x 106 / recurrence frequency..pulse repetition time = 833.33..maximum range = 833.33/2 x 0,162 = 67.5nm...also.velocity of light = 300000km/s.range = 300000/prf x 2.range = 300000/1200 x 2.range = 125km ==> 67,5nm.
Question 217-33 : The frequency of an ssr ground transmission is ?
1030 +/ 0.2 mhz.
Question 217-34 : The doppler navigation system is based on ?
Radar principles using frequency shift.
.doppler principle.the relative motion between transmitter and receiver causes a proportional frequency shift fd which is known as doppler shift, doppler effect or doppler frequency...transmitter and receiver are screened from each other but use the same aerial. beams are transmitted with a depression angle of 60 and 70 degrees and the receiver measures the reflected frequency shift caused by aircraft's speed along track, ground speed, speed across track and drift...as the transmitter and receiver get closer, a positive shift occurs in fd and as they move far apart, a negative shift occurs in fd.
Question 217-35 : In which mode of operation does the aircraft weather radar use a cosecant radiation pattern ?
Mapping.
. boeing 737ng navigation displays in map mode. 2613
Question 217-36 : The main factor which determines the minimum range that can be measured by a pulsed radar is pulse ?
Length.
.pulse length defines the minimum theoretical range of a radar.
Question 217-37 : Complete the following statement..aircraft surface movement radar operates on frequencies in the i.......... band employing an antenna that rotates at approximately ii.......... revolutions per minute it is iii......... possible to determine the type of aircraft from the return on the radar screen. ?
I shf ii 60 iii sometimes.
Question 217-38 : The maximum pulse repetition frequency prf that can be used by a primary radar facility in order to detect targets unambiguously at a range of 50 nm is. pps = pulses per second ?
1620 pps.
.range = c / 2f..f pps = c velocity of light / 2 x range..range= 50 nm..f = 162000 nm/s / 2 x 50..f = 1620 pulses per second.
Question 217-39 : Ignoring pulse length and fly back, a radar facility designed to have a maximum unambiguous range of 50 km will have a prf pulses per second of ?
3000.
.maximum range = velocity of light x 1/ prf..50 km = 300000 x 1/prf..prf = 300000 / 50 = 6000..but we have to ignore pulse length and fly back, so 6000/2.
Question 217-40 : Which combination of characteristics gives best screen picture in a primary search radar ?
Short pulse length and narrow beam.
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