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Question 202-1 : An aircraft is on hdg 030 and on a qdm 320 to an ndb. turning left towards the ndb, the pilot notices the adf needle moving rapidly to the left. why ? [ Exam pilot ]
Dip.
Los reference 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 in a bank. this is because the adf receiver system 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.
Question 202-2 : A crew is briefing for a procedural vor approach that requires a procedure turn for their destination airport, which involves a 80° turn to the left.. ?
260° turn to the right to intercept the inbound track.
Refer to figure...icao doc 8168..3.2.2 reversal procedure..b 80°/260° procedure turn see figure i 4 3 1 b , starts at a facility or fix and consists of..1 a straight leg with track guidance. this straight leg may be timed or may be limited by a radial or dme distance..2 an 80° turn..3 a 260° turn in the opposite direction to intercept the inbound track...the 80°/260° procedure turn is an alternative to the 45°/180° procedure turn a above unless specifically excluded.
Question 202-3 : According to the ils coverage area as defined by icao annex 10, the pilot will be guaranteed a reliable signal from the localizer at… ?
20 nm from the threshold on an inbound course and 8º displaced from the localizer centreline.
Glidepaththe glide path equipment shall provide signals sufficient to allow satisfactory operation of a typical aircraft installation in sectors of 8 degrees in azimuth on each side of the centre line of the ils glide path, to a distance of at least 18.5 km 10 nm up to 1.75 and down to 0.45 above the horizontal or to such lower angle, down to 0.30 , as required to safeguard the promulgated glide path intercept procedure.localizerthe localizer coverage sector shall extend from the centre of the localizer antenna system to distances of 46.3 km 25 nm within plus or minus 10 degrees from the front course line 31.5 km 17 nm between 10 degrees and 35 degrees from the front course line 18.5 km 10 nm outside of plus or minus 35 degrees from the front course line if coverage is provided in this case, we know localizer coverage up to 25 nm ± 10° and 17 nm ± 35°. now to be guaranteed coverage, the aircraft should be within these limits. therefore 27 nm ± 8° => outside coverage area of 25 nm.19 nm ± 13° => outside coverage of 10° from centerline.10 nm ± 38° => outside max of 35° from centerline.20 nm ± 8° => within 25 nm and ± 10° of centerline
Question 202-4 : What does the class letter associated with vdf bearings relate to ?
Level of accuracy.
According to icao annex 10, the vdf information is divided into four classes a, b, c and d. the classes are defined by the range of accuracy defined by degrees, based on the following table... . . classes. accurate to a range within. . . class a. ± 2º. . . class b. ± 5º. . . class c. ± 10º. . . class d. worse than class c
Question 202-5 : According to icao doc 8168, the maximum safe deviation below the glide path during ils approach is indicated by a half scale deflection on your instrument. the indicated deflection is more than half scale deflection, what shall the pilot do ?
Initiate a go around.
Icao doc 8168. 5.5.5 protection of the precision segment5.5.5.2 the protection area assumes that the pilot does not normally deviate from the centre line more than half scale deflection after being established on track. thereafter the aircraft should adhere to the on course, on glide path/elevation angle position since a more than half course sector deflection or a more than half course fly up deflection combined with other allowable system tolerances could place the aircraft in the vicinity of the edge or bottom of the protected airspace where loss of protection from obstacles can occur. the maximum allowed safe deviation of the aircraft is half scale deflection. in case of a larger deflection the pilot should initiate a go around.
Question 202-6 : An aircraft is flying a magnetic heading of 120º and the rbi shows the ndb at a relative bearing of 270º. choose the correct statement ?
The magnetic bearing to the beacon is 030º.
Refer to figure.. magnetic heading 120º. relative bearing of the ndb from the aircraft 270ºmagnetic bearing from the aircraft to the ndb = magnetic heading mh + relative bearing of ndb from the aircraft. magnetic bearing from the aircraft to the ndb = 120º + 270º = 030º maintaining a magnetic heading of 120º, the magnetic bearing from the beacon is 030º. incorrect.. the magnetic bearing of the aircraft from the ndb will be the reciprocal of 030º 030º + 180º = 210º turning into a magnetic heading of 030º, the magnetic bearing to the beacon will be 210º. incorrect.. if we turn into a magnetic heading of 030°, the aircraft horizontal axis will coincide with the line that connects the aircraft and the ndb. therefore, the relative bearing will be 000º/360º.. magnetic bearing from the aircraft to the ndb = magnetic heading mh + relative bearing of ndb from the aircraft magnetic bearing from the aircraft to the ndb = 030º + 000º = 030º
Question 202-7 : Preparing for the approach, the flight crew tune two ndb frequencies which are situated in similar geographical areas. ndb1 has a significantly higher power output than ndb2. what is correct regarding the ndb ranges ?
Ndb1 has a greater range.
Several factors affect the range of an ndb transmission. the most significant effect is the transmission power output. depending on the desired range of operation, different types of ndbs have different transmission powers. the range obtained is proportional to the square of the power transmitted. as a result, a range twice as far requires four times the power. the ndb range is also limited by frequency, lower frequencies result in longer ground waves.
Question 202-8 : Under what circumstances would an adf bearing be affected by dip error ?
The aircraft banking.
Los reference 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 in a bank. this is because the adf receiver system 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.
Question 202-9 : Which of the following procedures is used to identify an ndb station ?
In case of a2 modulation, use the adf function.
062.01.01.03.04 state that the following abbreviations classifications according to international telecommunication union itu regulations are used for aviation applications n0n carrier without modulation as used by non directional radio beacons ndbs a1a carrier with keyed morse code modulation as used by ndbs a2a carrier with amplitude modulated morse code as used by ndbs a3e carrier with amplitude modulated speech used for communication vhf com.to identify a modulated ndb station, the carrier wave is modulated in amplitude a2a with a tone of 400 or 1 020 hz, which provides the morse code for identification.to listen to the identification of an unmodulated non a1a ndb, the pilot must activate a system known as the beat frequency oscillator bfo by switching it on. the bfo remains active as long as the beacon is in use for navigation. this allows the pilot to identify the ndb station.let's analyze each option separately 'in case of a3 modulation, use the vhf com function.' incorrect. the onboard adf equipment does not have a vhf com function. additionally, a3 modulation is utilized in vhf communications, not in ndb navigation.'in case of n0n modulation, use the bfo function.' incorrect. while all ndb stations transmit n0n carrier waves, the bfo is only necessary when the wave type includes a1a modulation. therefore, for n0n a2a transmissions, which are still a type of n0n wave, the bfo is not required.'in case of a2 modulation, use the adf function.' correct. the adf function represents the standard operational mode of adf equipment. when selected, it enables the pilot to hear the identification signals of n0n a2a transmissions.'in case of a1 modulation, use the ant function.' incorrect. in most light aircraft equipped with adf equipment, the antenna ant function is activated when the adf button is in the out position. this function is used to test the adf equipment and improve the audio reception of identifications from ndb stations that transmit n0n a2a signals. while the ant function is selected, the adf needle will be deactivated and will rotate 90° from its current indication.
Question 202-10 : How do you tune mls system in your aircraft, select two of the following combination 1. approach can only be upload from fms..2. select the appropriate channel number..3. course obtained from atc only..4. select the appropriate glideslope angle for approach. ?
2 and 4.
Refer to figure...mls principle of operation..mls employs the principle of time division multiplexing tdm see figure 10.5 whereby only one frequency is used on a channel but the transmissions from the various angle and data ground equipments are synchronised to assure interference free operations on the common radio frequency...the airborne equipment is designed to continuously display the position of the aircraft in relation to the preselected course and glide path along with distance information during approach as well as during departure.
Question 202-11 : The vdf class letter indicates the accuracy of the bearing information in terms of the ?
Angle in degrees.
According to icao annex 10, the vdf information is divided into four classes a, b, c and d. the classes are defined by the range of accuracy defined by degrees, based on the following table... . . classes. accurate to a range within. . . class a. ± 2º. . . class b. ± 5º. . . class c. ± 10º. . . class d. less than class c
Question 202-12 : Navigating to an ndb at dusk, you notice the adf needle swinging erratically. what could be the reason ?
Interference occurs between the ground wave and sky wave causing the signal to fade when the two waves are out of phases.
Refer to figure...night effect..night effect is due to the interference between ground waves and sky waves emitted by the same ndb station...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. returning sky waves take a longer propagation path than ground waves so they are often out of phase...night effect can be detected by listening for fading on the carrier wave bfo on and by the instrument hunting. it is most likely at dawn or dusk.
Question 202-13 : It is expected for pilots to apply wind correction angles to the aircraft heading while following the tracks depicted in a procedure, as described in pans ops, doc 8168 , procedures for air navigation services — aircraft operations.. ?
The head or tail of the needle may point slightly left or right of the top of the instrument when maintaining the appropriate qdm or qdr.
Refer to figure.. the needle of an adf always points towards the ndb that it is tuned into. relative bearings are measured from the aircraft heading to the ndb. when tracking towards a ndb, the relative bearing equals to 360 degrees minus wind correction angle. when tracking away from a ndb, the relative bearing equals to 180 degrees minus wind correction angle. note the wind correction angle is added to track to give headings. it can be seen that the head or tail of the needle need not be pointing straight up when there’s wind to correct for. hence once the aircraft is established on the depicted track the head or tail of the needle will point straight up on the instrument regardless of wind conditions. is not the correct option. even if there’s no wind, the head of the needle will be pointing at 180 degrees relative to the top of the instrument when tracking outbound of ndb. thus the head of the needle will be pointing at 3600 when the aircraft is established on the inbound or outbound track. is incorrect. from the diagram it is clear that relative bearing only equals to the magnitude of the wind correction angle when tracking inbound and the wind correction angle is negative. therefore, the relative bearing will be equal to the wind correction angle required to maintain the depicted track towards or away from the ndb. is incorrect as well. the only option left is the head or tail of the needle may point slightly left or right of the top of the instrument when maintaining the appropriate qdm or qdr. which is correct when crosswind is light. when crosswind is strong, the head or tail of the needle may point significantly from the left or right of the instrument though when maintaining the appropriate qdm or qdr. however, it is the most sensible answer choice present in this question.
Question 202-14 : You are flying in canada using a vor to navigate. you are on the 190° radial, the variation at the vor is 2°w and at the aircraft is 2°e. the true bearing from the vor to the aircraft is... ?
188°
Refer to figure...usually a magnetic heading, vor or ndb reading magnetic too is provided which needs converting to a true heading/bearing by applying magnetic variation...we have 3 cases now..aircraft heading apply the variation at the aircraft’s position...find out the value of the variation from the chart and apply it to your heading...ndb bearing apply the variation at the aircraft’s position...because this is where the bearing is obtained from, the ndb equipment calculates the bearing information at the equipment onboard so you need to apply the variation at the same location...vor radial apply the variation at the vor’s position...because this is where the radial is obtained from, the vor station, whatever the vor is conventional or doppler it identifies the radial where you are on, and then send it to you, so you have to apply the variation where the station is located at...as far as the variation at the vor station is 2w and following the rule of variation west magnetic is best so we have to subtract the variation from the readout radial to get the true bearing in order to plot it on the chart or for any other usage 190° 2° = 188°...note in canada airspace, northern domestic airspace nda is the area of compass unreliability within which runways and navaids are oriented to true north. this question appeared in the exam exactly in this way. so the examiner has assumed that we are in the southern domestic airspace of canada.
Question 202-15 : Icao doc 8168 describes, amongst others, holding procedures. the pilot should start the timing for the outbound leg of the holding pattern when passing abeam the holding fix or wings level, whichever is later. ?
Approximately 090 degrees or 270 degrees.
Refer to figure...the question references an rbi, which is a relative bearing indicator, also know as a fixed card adf. this only shows the direction to an ndb from the direction you are currently facing, and is the simplest type of adf display...the question mentions that you should start the timing for the outbound leg when wings level or abeam the fix, whichever is later. it then specifies that we are already wings level, so we simply have to identify at which point we are abeam the ndb...this would be whenever the rbi shows 90 or 270 , as holding patterns can be standard right hand turns or non standard left hand turns , which would place you on opposite sides of the fix.
Question 202-16 : When intercepting a selected radial, the flight director indicates the ?
Optimum instantaneous bank angle to reach the selected radial.
The flight directors provide information for the pilot to join a desired path with the optimum attitude. flight director information supplied by a fd computer is presented in the form of command bars on the attitude director indicator adi. the vertical command bar of the fd supplies information about the direction and magnitude of the corrections to be applied to the bank angle of the aircraft since it is always associated with the roll channel. therefore, when intercepting a selected radial, the fds will indicate the optimum instantaneous bank angle to reach the selected radial.
Question 202-17 : An aircraft is being radar vectored downwind for the ils to runway 27 of a regional airport. the ils for runway 27 has been tuned in and displayed on the hsi. ?
Side lobes from the ils localiser antenna.
Ils localisers and glideslopes work in very similar ways, they both produce 2 different lobes of signal, one lobe which is modulated at 150hz, and one lobe modulated at 90hz. the glideslope signal is in the uhf radio band and the localiser is vhf, similar to vors. the amount of each lobe received is then used to calculate your position in relation to the localiser and glideslope.unfortunately, in creating these 'lobes', unwanted sidelobes are produced by both the localiser and the glideslope. for the localiser, they are just outside of the +/ 35 ils usable zone, and they are reverse sensing. glideslopes have sidelobes also, which are seen as false glideslopes, reverse sensing and steeper than the true glideslope.the phenomenon in this question is occuring at about 45 south of the inbound localiser course, and the aircraft receiver is showing that it is passing through the localiser, but in the reverse sense a quick sketch is very useful to determine this. this is the perfect presentation of a localiser sidelobe, and should be disregarded by the pilots. localiser sidelobes are required to be known in learning objective 062.02.05.01.09... note this could not be a 'siting error' as, even though they can occur for ils localisers, they are erratic, very short lived fluctuations of the ils indicator due to beam reflections, not beam bending. they are also not a smooth, reverse sensing error as a localiser sidelobe is.
Question 202-18 : You are making an approach to runway 25 at daytona beach which has a published ils back course approach. which of the following statements is correct with respect to localiser indications on an omni bearing indicator obi and a horizontal situation indicator hsi ?
Reverse sensing will always occur on the obi regardless of the course set the hsi will sense correctly with the front course set.
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. using an omni bearing indicator obi display will always give a simple, fly left or fly right, localiser display no matter the chosen obs course...a horizontal situation indicator hsi has a simple course deviation indicator 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 produce exactly the same display as the standard obi, fly left or fly right. the direction of the cdi does not affect the cdi indications, just how we view them...when using a ils back course, the usual signal lobes are reversed, so an obi display will be absolutely reverse sensing. this is the same for the cdi in the centre of the hsi, reverse sensing indications. however, the cdi in the middle of the hsi can be turned to face the front course of the standard ils needle pointing downwards when flying the back course which reverses our view of the indications again. this gives correctly sensing localiser indications for the hsi during a back course approach, only if the cdi is set to the course of the standard inbound ils.
Question 202-19 : How can an air traffic control unit determine the position of an aircraft without the use of radar ?
By using auto triangulation provided from several vdf bearings from different stations.
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. the computer allows the triangulation to be done immediately...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.
Question 202-20 : Which of the following options are the correct frequency band, propagation type, and range of usable frequencies for an ils localiser ?
Vhf, space waves, 108.10 mhz to 111.975 mhz.
Ils localisers operate on a frequency between 108.10 and 111.96 mhz vhf , in the bottom half of the band that is used by vors. as such, they propogate as space waves, which are line of sight radio waves. the linked glide path signals operate on a frequency between 328.6 and 335.4 mhz uhf , and also travel as space waves.
Question 202-21 : An aircraft is equipped with a dme receiver that provides a ground speed read out. it is being flown at fl70 and is currently crossing radial 090 from a vor dme station at an indicated dme range of 20 nm. the aircraft is flying in a north easterly direction. ?
Inaccurate as the aircraft is crossing the radials rather than flying an inbound or outbound radial.
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.
Question 202-22 : Which of the following could give sufficient guidance to the pilot when flying a curved mls approach ?
Flight director bars
An microwave landing system mls works in a similar way to an ils, with a ground station or multiple transmitting information to aircraft on the approach, and an airborne receiver interpretting that data, and providing guidance to the pilot. an mls is a precision approach, and can be segmented, or even curved, due to its 3d design, and has far fewer drawbacks than an ils system. as it provides both horizontal and vertical guidance, it can be flown very well by an autopilot, and in some cases can be setup to provide flare guidance for an autoland, etc. as an alternative, it can also be manually flown following flight director guidance in the horizontal and vertical sense, and this is possible for all mls approaches, even the complex curved ones...it would not be possible for a cdi, rmi, etc. to provide such guidance for curved approaches, as they do not follow a straight line like an ils does, and also rmi lacks in the ability to provide vertical guidance.
Question 202-23 : A dme ground station can generally respond to a maximum of 100 aircraft at once. what is the reason for this limitation ?
Saturation of the dme ground station working on only one receive frequency and one transmit frequency.
Distance measuring equipment dme is a type of secondary radar system that provides slant range using the pulse technique. the aircraft’s interrogator transmits a stream of psuedo random omni directional pulse pairs on the carrier frequency of the ground transponder. the ground transponder then receives these, waits 50 microseconds, and repeats those pulse pairs outwards at a frequency 63 mhz above the interrogation frequency...the airborne system identifies its own unique stream of pulse pairs and measures the time of arrival electronically, between the start of the interrogation and the reception of the ground transponder's replies...as there is only one interrogation frequency and one reply frequency for each dme ground station, they can only service a certain number of pulses per second, and it ends up meaning that the dme becomes saturated with around 100 aircraft using it, and it will then prioritise the pulses with the strongest signal...aircraft attempting to search for a dme emit 150 pulses per second, but after 15000 pulses, reduce that to 60 pulses per second, and later on to 24 pulses per second when fully 'locked on'. as the dme can only handle 2700 pulses per second reliably, this ends up being approximately 100 aircraft, some searching, some locked on.
Question 202-24 : According to icao doc. 8168, an aircraft can be considered established on a vor approach when within what error margin ?
Half scale deflection.
Icao doc. 8168 part 3.3.4. an aircraft is considered established when it is. a within half full scale deflection for the ils and vor or. b within ±5° of the required bearing for the ndb.learning objective 062.02.03.04.01 define that the accuracy the pilot has to fly the required bearing in order to be considered established on a vor track when flying approach procedures, according to icao doc 8168, has to be within the half full scale deflection of the required track.
Question 202-25 : 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 300° radial. ?
298°
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 300°. radials from vors are in magnetic, so we know the magnetic bearing from the vor to the aircraft is 300° 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 300° 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 298° 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.
Question 202-26 : A pilot is flying an ndb holding pattern. they should continuously monitor the… ?
Morse code as a means to identify a potential failure of the ndb.
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 like when it is out of range of the receiver. this is not a very reliable failure indication, so the pilot should continuously monitor the ndb's morse code identifier, which would stop transmitting in the event of an ndb failure, and would be a much more timely method of noticing a failure. this is obviously not a nice thing to do, as it is often a very annoying identifier noise, another reason ndbs are such a bad navigational aid in modern times.
Question 202-27 : In the legend of a navigation chart, a beacon is mentioned to be a tvor. which description of the tvor is correct ?
A vor station with a shorter range, used as part of the approach and departure structure at major aerodromes.
Vor applications..vors can be classified as follow... a conventional vor cvor is a first generation vor transmitter which emits a spinning limacon shaped amplitude modulating variphase signal.. a doppler vor dvor is a second generation vor transmitter with no moving parts, and sends a frequency modulating variphase signal through its many antennas which circle the beacon to use the doppler shift effect.. a terminal vor tvor is a low power beacon with shorter range, used as part of approach and departure procedures.. a broadcast vor is usually a terminal vor with a voice broadcast giving out the airfield weather atis superimposed on the carrier wave.. a test vor vot is a very low power beacon sited at some airfields. it puts out a constant phase difference of zero in all directions. this allows aircraft to test the accuracy of their equipment on the ground....it is important to note, with the other possible answers, that the tvor in question is not just for the inbound runway course, but is for all around the airfield, and is useful for both approach and departure...note do not confuse a tvor with a test vor
Question 202-28 : Which of the following statements correctly describe the principles of operation of distance measuring equipment dme 1. the aircraft's primary radar output transmits a signal that triggers a reply from the dme station.. 2. ?
2 and 3
Distance measuring equipment dme is a type of secondary radar system that provides slant range using the pulse technique. the aircraft’s interrogator transmits a stream of pseudo random omni directional pulse pairs on the carrier frequency of the ground station receiver. the ground transponder then receives these interrogation pulses, waits 50 microseconds, and sends a reply, repeating those pulse pairs outwards at a frequency 63 mhz above the interrogation frequency...the aircraft's dme system identifies its own unique stream of pulse pairs and measures the time of arrival electronically, between the start of the interrogation and the reception of the ground transponder's replies. this then can be calculated into a line of sight distance to the ground station, known as the slant range.
Question 202-29 : Determine the distance which will be shown on a dme display when the aircraft is at fl 360 and 6 nm plan range from the dme station..for the calculation use the following assumptions/approximations..qnh is 1013 hpa..pressure altitude is true altitude. ?
8 nm
Refer to figure...the question states that we can regard pressure altitude to be the true altitude. therefore, true altitude equals 36 000 ft.... 36 000 ft / 6 076 = 6 nm approx....what we have is isosceles perpendicular triangle since plan distance and altitude are both equal to 6 nm...dme measures the slant distance hypotenuse. we already know lengths perpendicular of perpendicular sides...using the pythagoras theorem..x2 = 62 + 62..x2 = 72..x = 72 = 8.48 nm closest answer is 8 nm
Question 202-30 : A procedural vor approach using a procedure turn is to be flown. the outbound leg follows the 098° radial from the vor to a dme range of 6.0 nm, followed by a left turn onto a track of 018° m , what should the next turn be ?
A right turn onto a track of 278° m to intercept the inbound track.
Refer to figure...in a procedural approach, often an aircraft will need to perform a reversal manoeuvre, in order to get from an outbound to an inbound track. there are many different ways this can be done, and the chosen method will be dictated clearly on the approach plate. some of the available methods are the 45 180 procedure turn, the racetrack pattern, the teardrop procedure, and the 80 260 procedure turn....icao doc 8168..3.2.2 reversal procedure..b 80°/260° procedure turn see figure i 4 3 1 b , starts at a facility or fix and consists of..1 a straight leg with track guidance. this straight leg may be timed or may be limited by a radial or dme distance..2 an 80° turn..3 a 260° turn in the opposite direction to intercept the inbound track...the 80°/260° procedure turn is an alternative to the 45°/180° procedure turn a above unless specifically excluded...video explanation
Question 202-31 : After tuning the correct ils frequency, and receiving the correct ident, the pilot notice that the localiser loc and glide path gp indicators are both showing warning flags. the pilot confirms that the aircraft is within the prescribed coverage area of the ils. ?
The aircraft receives modulating frequencies of 90 and 150 hz at a rate of 0%.
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 within the coverage area of the ils, and receiving the ident, that means that the carrier wave for the correct loc is definitely being received, but showing flags for both loc and gs is not what you would expect in normal operation. when flags are shown, it is due to any of the items listed in the lo above, or possibly due to the received signal being below a certain strength. this narrows down the possible failures to a modulation problem...also, the other possible answers are wrong as... selected course does not affect ils signals or indication.. any more than full scale deflection within the coverage area shows exactly that, full scale deflection.. an aircraft ahead of yours might cause a momentary change in the ils indication due to signal reflection, but this woud be a tiny blip indeed.
Question 202-32 : After tuning and receiving a correct ident, you become established on an ils and follow the approach. on short final, the localiser loc and glide path gp indications disappear, and both show warning flags instead. what is the most probable explanation for the warnings ?
The modulation of the 90 hz and 150 hz signals is 0%.
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...as we have identified and followed the ils down to short final by this point, we know that this sudden appearance of flags is a fault of some kind. when flags are shown, it is due to any of the items listed in the lo above, or possibly due to the received signal being below a certain strength. this narrows down the possible failures to a modulation problem...also, the other possible answers are wrong as... the lack of loc/gp ident signals would not be a reason for showing flags. loss of both carrier frequencies would cause this to happen, but that is not one of the available answers.. there is no cone of confusion for ils transmitters, and definitely should be no similar error regions on short final.. signal strength that is too high would not cause distortion.
Question 202-33 : An aircraft is on the 290° radial from a nearby vor. the magnetic variation at the vor is 5°e and the magnetic variation at the aircraft is 7°e. what true track does the aircraft need to fly to go directly to the vor ?
115°
The aircraft is on radial 290°, which is a magnetic bearing from the vor. to turn this into a true bearing, we can use the saying variation west, magnetic best.. variation east, magnetic least.in this case, we must use the variation at the vor, as this is where the radials come from, which is 5° east. an easy way to remember this is that 'v' is for variation and vor, so we should use the magnetic variation at the vor.magnetic is least, therefore the true bearing from the vor is going to be 5° more than 290° m , so will be 295° t.the bearing from vor to aircraft is 295° t , so the true track to fly the opposite direction is 295 180 = 115° t , this is the true track to be flown direct to the vor.
Question 202-34 : An aircraft is radar vectored onto a cat i ils approach using a hsi. the final approach track is 164° and the magnetic variation is 4°w. the pilot is expecting approximately 6° right drift on final approach, what should they set the course selector to on the hsi ?
164°
An ils inbound track is based on magnetic courses, and therefore there is no need to apply variation, as the hsi horizontal situation indicator is also based on magnetic, as it is slaved to the magnetic field by the remote reading compass system...it is also important to note that the hsi display will actually not depend on the selected course, as an ils course deviation indicator cdi does not depend on selected course, and just works off the differing modulation between two localiser lobes to give fly right or fly left indications. the cdi in the middle of the hsi will just display fly left and fly right indications, no matter the selected course and can therefore reverse sense if twisted backwards...the hsi should therefore be set up with the inbound magnetic course selected, as this will give the correct indications and an aide memoir of the inbound course to the pilot all the way down the approach...the inbound heading of the aircraft accounting for wind correction angle would not be used for many important reasons.
Question 202-35 : Which of these options correctly describes the basic principles of operation of an mls ?
The time interval between the to and from scans in azimuth and elevation determines the aircraft position within the coverage area.
Refer to figure...the principles of operation of microwaves landing systems mls are actually quite simple to understand. there are 2 main and 1 extra transmitters providing information to the aircraft. the first one provides information about how far an aircraft is horizontally from the correct inbound course, called azimuth guidance similar to ils localiser. the second one provides similar information about how far the aircraft is from the correct glide path, called elevation guidance...there is a third transmitter that is used to allow curved and segmented mls procedures to take place also, called the dme/p, which is a more precise version of a standard dme. with this in use also, the aircraft can have the knowledge of its 3 dimensional position for much more complex not straight in approaches...the azimuth and elevation transmitters work in the same way, they emit a beam that 'scans' the sky, side to side to and fro for the azimuth guidance, up and down for the elevation beam. the aircraft then detects how much time passed inbetween the beams being detected, between the 'to' and the 'fro' beam, for instance , and can very accurately detect its angular distance from the inbound course/glide path...the azimuth beam does not constantly scan to fro to fro..., but has a break whilst the elevation beam does it's own scan, and they alternate with each other. with data being passed also through the frequency at set intervals.
Question 202-36 : What is one of the main differences between cat ii and cat iii mls approaches ?
Only cat iii allows no decisions height.
Refer to figure...cat ii and cat iii minima are not specific to the mls microwave landing system , but are much more commonly used on ils approaches as mls approaches barely exist anymore...it can be thought of as a scale, cat i can get an aircraft down to 200ft, cat ii can get further down to 100 ft, etc. then there are 3 levels of cat iii minima, which do actually have varying rvr requirements depending on authority, but the annex above gives the basic values...as can be seen in the annex, the first time a full autoland can be completed no decision height is cat iii, meaning that this is the correct answer...both cat ii and cat iii require a radio altimeter, and both have rvr requirements except cat iiic, but this is only one section of cat iii minima , so all the other answers are incorrect...please note that this annex uses the old system. we believe that easa may be in the process of transitioning to the new system of minima. see the short explanation in the comments for more, whilst we find out what easa are currently considering is correct, thank you.
Question 202-37 : There are two primary methods of flying to or from an ndb. complete the following statement from the options below.. 1 may be used to fly 2 the ndb while 3 may be used to fly 4 the ndb. ?
1 homing 2 to 3 tracking 4 to or from
Refer to figure.. there are 2 different ways to fly using ndb's, the difference between the two is how the wind is dealt with.in the 'easiest' way to fly, homing, the pilot can simply point at the ndb relative bearing 0º and keep the needle on the nose of the aircraft. the problem is that the wind will push them off track if there is any crosswind , but the aircraft will just change its heading to point at the ndb again, meaning that they end up flying a curved path towards the beacon, ending almost completely into wind. this is not efficient, and can cause dangers with terrain clearance and other traffic. a visual representation can be seen in the annex above.tracking, on the other hand, is a more correct way to fly using an ndb, and this requires the pilot to choose an inbound or outbound course from the beacon, and maintain it by applying a wind correction angle to their heading, so that their track is always directly towards or away from the ndb, on the chosen radial. it is a little more complex to fly, but far more useful.not that homing can only take you to an ndb, whereas the tracking technique can guide aircraft to and from ndbs.
Question 202-38 : A crew is briefing for a procedural vor approach that requires a procedure turn for their destination airport. this procedure turn consists of a straight track with outbound track guidance followed by a turn of 45° left, followed by a... ?
Timed straight leg without track guidance and a 180° turn to the right to intercept the inbound track.
Refer to figures...in a procedural approach, often an aircraft will need to perform a reversal manoeuvre, in order to get from an outbound track to an inbound track. there are many different ways this can be done, and the chosen method will be dictated clearly on the approach plate. some of the available methods are the 45 180 procedure turn, the racetrack pattern, base turns, and the 80 260 procedure turn. the one in question has started with a 45º turn, so must be the 45 180 procedure turn. see the annexes above for the specific manoeuvre and the other main reversal procedures....icao doc 8168..3.2.2 reversal procedure..3.2.2.3 a 45°/180° procedure turn see figure ii 5 3 1 a , starts at a facility or fix and consists of..1 a straight leg with track guidance. this straight leg may be timed or may be limited by a radial or distance..measuring equipment dme distance..2 a 45° turn..3 a straight leg without track guidance. this straight leg is timed. it is..i 1 minute from the start of the turn for category a and b aircraft and..ii 1 minute 15 seconds from the start of the turn for category c, d and e aircraft and..4 a 180° turn in the opposite direction to intercept the inbound track.
Question 202-39 : Which of the following options states the correct frequency band, propagation path and frequency range for an ndb ?
Lf and mf, surface waves, 190 khz to 1750 khz.
Learning objective 062.02.02.01.05 state that the ndb operates in the lf and mf frequency bands...learning objective 062.02.02.01.06 state that the frequency band assigned to aeronautical ndbs according to icao annex 10 is 190 1750 khz...learning objective 062.01.03.04.02 state that radio waves in lf, mf and hf propagate as surface/ground waves and sky waves..this question involves knowledge of all the above learning objectives. there is not much more to explain, except that ndbs are only properly usable when they travel as surface waves radio waves which cling to the surface of the earth.. this is because the direction of the incoming beam matters to their accuracy by their very nature, and is much less accurate if it has been 'reflected' off the ionosphere. it is for this reason that there is a 'night effect', when the sky waves reflect much more from the ionosphere and return to the aircraft, interfering with the surface waves to cause difficulty in measurements.
Question 202-40 : A pilot of an aircraft flying in the daytime at fl80 on heading 030° m is instructed by atc to route directly towards an ndb. the adf is already tuned to this ndb and identified correctly, with a qdm of 340° m and about 8 nm away. ?
Dip error
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. this is called 'dip error'. when tracking ndbs in real life, dip error is actually quite large, and means that the adf needle is almost useless whilst in the turn. it is also very difficult to correct for accurately.
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