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A student pilot has just learnt that meteorological information for aircraft en ? [ Multiple protocol ]

Question 178-1 : Single sideband receiver vhf receiver lf/mf receiver double sideband receiver

Refer to figure . learning objective 062 01 01 03 03 state that hf meteorological information for aircraft in flight volmet and hf two way communication use a single sideband when we want to send information via radio waves we have to modulate the carrier wave somehow this is the process of adding information to it there are a few ways to do this in the early days of radio it was done by sending pulse of the carrier wave as morse code pulse modulation these days we can modulate the amplitude of the carrier wave to carry our information or we can modulate the frequency slightly to carry information also amplitude modulation is easier to do and far easier to represent visually the peaks and troughs of our carrier wave are modified to create our information wave over the top of each peak and the same information wave under each trough the wave over the peaks is one sideband and the wave under the troughs is the other sideband two sidebands are created but when we send hf radio signals we remove one sideband to reduce the required power of the transmitter and the required bandwidth this means to accept hf radio our receiver has to be of the single sideband ssb type this question is a bit too ambiguous as it does not mention that we are picking up a hf volmet broadcast in simple terms instead it hints at the hf part as it is a long haul flight currently en route and that it is a volmet as they are trying to pick up 'meteorological information' the learning objective above is very clear on this though and once that lo is known it is obvious what the question writer is getting at exemple 278 Single sideband receiver.Single sideband receiver.

Which of the following options contains the correct frequency band propagation ?

Question 178-2 : Hf 3 mhz to 30 mhz surface and sky waves vhf 108 mhz to 117 975 mhz sky waves mf 190 khz to 1750 khz surface and sky waves hf 3 mhz to 30 mhz surface waves only

Refer to figure . learning objective 062 01 01 03 03 state that hf meteorological information for aircraft in flight volmet and hf two way communication use a single sideband . 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 contains a mixture of two different learning objectives one is to know which frequency range of radio waves use a single side band hf and the second is to know how hf waves propagate when we want to send information via radio waves we have to modulate the carrier wave somehow this is the process of adding information to it there are a few ways to do this in the early days of radio it was done by sending pulse of the carrier wave as morse code pulse modulation these days we can modulate the amplitude of the carrier wave to carry our information or we can modulate the frequency slightly to carry information also amplitude modulation is easier to do and far easier to represent visually the peaks and troughs of our carrier wave are modified to create our information wave over the top of each peak and the same information wave under each trough the wave over the peaks is one side band and the wave under the troughs is the other side band two side bands are created but when we send hf radio signals we remove one side band to reduce the required power of the transmitter and the required bandwidth this means that hf transmissions are single side band ssb also to note hf radio waves are between 3 30 mhz the range just below familiar vhf and they travel as both surface waves clinging on to the surface of the earth and sky waves bouncing off the ionosphere exemple 282 Hf, 3 mhz to 30 mhz, surface and sky waves.Hf, 3 mhz to 30 mhz, surface and sky waves.

International telecommunication union itu classification abbreviations used in ?

Question 178-3 : 1 a2a 2 ndbs 1 a2a 2 vors 1 a3e 2 ndbs 1 a3e 2 vors

Learning objective 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 .the itu international telecommunication union produce a classification system for each type of radio wave describing in 3 characters how a radio wave is modulated modulation is the act of putting information onto a radio wave and includes pulse modulation frequency modulation or amplitude modulation the first letter is how the wave is modulated the second character is what type of information is modulated onto the wave digital analogue etc and the third is the information output morse code voice etc .the 3 character abbreviation for an old style ndb ident is a1a these have keyed morse code modulation bfo mode must be used to here the ident and a newer ndb ident is a2a which has amplitude modulated morse code so you can listen to it in any mode the ndb carrier wave is n0n it is not modulated and carries no information .the learning objectives also state that we must know the classification for vhf communication waves which is a3e as per the above lo .this is the limit of the learning objectives on these classifications you do not need to find and memorise the table exemple 286 (1) a2a; (2) ndbs(1) a2a; (2) ndbs

3 30 khz frequency band is referred to ?

Question 178-4 : Very low frequency vlf ultra low frequency ulf very high frequency vhf low frequency lf

As seen in the table below the very low frequency vlf band reaches from 3 khz to 30 khz frequency name frequency application very low frequency vlf 3 30 khz nil low frequency lf 30 300 khz ndb/adf medium frequency mf 300 3000 khz ndb/adf long range communications high frequency hf 3 30 mhz long range communications very high frequency vhf 30 300 mhz short range communication vdf vor ils localizer marker beacons ultra high frequency uhf 300 3000 mhz ils glide path dme ssr satelite communications gnss long range radars super high frequency shf 3 30 ghz radalt awr mls short range radars extremely high frequency ehf 30 300 ghz nil mnemonic to remember the frequency names . very very low frequency . lovely low frequency . maidens medium frequency . have high frequency . very very high frequency . useful ultra high frequency . sewing super high frequency . equipment extremely high frequency exemple 290 Very low frequency, vlf.Very low frequency, vlf.

Single sideband two way communication is used in what frequency band and how ?

Question 178-5 : Hf 3 30 mhz as ground waves and sky waves hf 3 30 mhz as ground waves only mf 3 30 mhz as ground waves mf 3 30 mhz as ground waves and sky waves

Refer to figure .learning objective 062 01 01 03 03 state that hf meteorological information for aircraft in flight volmet and hf two way communication use a single sideband .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 contains a mixture of two different learning objectives one is to know which frequency range of radio waves use a single side band hf and the second is to know how hf waves propagate .when we want to send information via radio waves we have to modulate the carrier wave somehow this is the process of adding information to it .there are a few ways to do this .in the early days of radio it was done by sending pulses of the carrier wave as morse code pulse modulation .these days we can modulate the amplitude of the carrier wave to carry our information or we can modulate the frequency slightly to carry information also ..amplitude modulation is easier to do and far easier to represent visually .the peaks and troughs of our carrier wave are modified to create our information wave over the top of each peak and the same information wave under each trough .the wave over the peaks is one side band and the wave under the troughs is the other side band .two side bands are created but when we send hf radio signals we remove one side band to reduce the required power of the transmitter and the required bandwidth .this means that hf transmissions are single side band ssb ..also to note hf radio waves are between 3 30 mhz the range just below familiar vhf and they travel as both ground waves clinging on to the surface of the earth also called surface waves and sky waves bouncing off the ionosphere .this can actually cause some interference when the two meet especially at night when the ionosphere is thinner exemple 294 Hf (3-30 mhz), as ground waves and sky waves.Hf (3-30 mhz), as ground waves and sky waves.

The pilot of an aircraft changes its heading to the right from 214º to 334º ?

Question 178-6 : 40 seconds impossible to calculate because we need the aircraft's tas 30 seconds impossible to calculate because we need the aircraft's angle of bank

Refer to figure .note this is certainly not a suitable question for rnav so should be appealed if seen in the exam ..if the turn is unbalanced an aircraft either slips into or skids out of the turn thereby reducing the aerodynamic efficiency of the aircraft to help correct for these unwanted conditions the aircraft is flown using the balance part of the turn and balance indicator.during a balanced turn the ball remains in the centre of the balance indicator and the pilot remains upright in the seat relative to the aircraft with no tendency to lean .rate of turn is the measurement of how long it takes for an aircraft to turn measured in degrees per second this is particularly important during instrument flying where rate 1 turns are usually carried out at a rate of 3° per second this means that the aircraft turns through 180° in 1 minute or 360° in 2 minutes a steeper angle of bank is required to carry out a rate 1 turn at higher airspeeds .to solve this exercise first we need to calculate how many degrees was the turn performed and then apply the rate of turn .334º 214º = 120º at 3º/second rate 1 turn .120/3º = 40 seconds exemple 298 40 seconds.40 seconds.

You are trying to get a bearing on an ndb in the hf frequency range in theory ?

Question 178-7 : Climb to increase your chance of capturing the sky wave climb to increase your chance of capturing the ground wave increase your distance from the ndb to better capture the ground wave fly towards the ndb to better capture the sky wave

Refer to figures .note this is a ridiculous question and when paired to these options is very misleading and nearly unanswerable appeal this question in the exam please send us any further feedback if you do see this question as we would certainly like to see if they change the options or if they accept the appeal we believe this question has already been appealed at least once so hopefully it will soon be gone completely ndbs non directional beacons emit their signals in the mf and lf frequency bands which allows them to propagate as sky waves bouncing off the ionosphere and surface waves sticking to the ground surface waves stick to the surface of the earth in a strange fight between reflection diffraction and refraction with the charged surface of the earth they can propagate very far in the right conditions and mostly maintain their direction over the earth other than when going from land to sea where they shift direction as part of the 'coastal effect' we can go through each option now to try and work out which could be most correct 'climb to increase your chance of capturing the sky wave 'this would give us a better chance of receiving a sky wave as the angles would be shallower so more chance of the waves 'bouncing' off the ionosphere due to total internal refraction however the bouncing off the ionosphere introduces large changes of lateral direction and we would not receive an accurate bearing but we would receive a stronger bearing we would argue that this is useless as we use ndbs for navigation so wildly inaccurate bearings are just as bad as no bearing at all 'climb to increase your chance of capturing the ground wave 'ground waves run along the surface of the earth and hold their direction much better than sky waves so this is how we usually pick up long range ndb bearings however we do not believe that climbing higher will aid us to do this 'increase your distance from the ndb to better capture the ground wave 'ground waves have limited distance the closer you are to the source the better the reception therefore this is wrong 'fly towards the ndb to better capture the sky wave 'before the 'first skip' distance of the sky wave no sky wave will be present and remember we do not want to get a sky wave anyway as it often has fading or is in the wrong direction giving us a bad bearing as you can see there is no good answer here and we believe that the assumption that you have to make to answer it is misleading exemple 302 Climb to increase your chance of capturing the sky wave.Climb to increase your chance of capturing the sky wave.

A pilot departs an aerodrome on the west coast of spain at dawn for a flight to ?

Question 178-8 : Space waves have no reflection by the ionosphere no surface waves fading by reflected signals and limited transmission power absorption by the ionosphere and no direct waves inversion of polarisation by the ionosphere and attenuation

Refer to figure . learning objective 062 01 03 04 01 state that radio waves in vhf uhf shf and ehf propagate as space waves . learning objective 062 01 03 03 01 define ‘space waves’ the electromagnetic waves travelling through the air directly from the transmitter to the receiver as the aircraft in this scenario is communicating with the ground station via vhf radio the radio signals will only propagate as space waves space waves are line of sight waves that go in straight lines only and therefore cannot go around obstacles including around the earth's horizon this means that there is a very well defined limit of how far vhf communications can be received from it is calculated with the formula range nm = 1 23 x height of transmitter ft + 1 23 x height of receiver ft as soon as the aircraft is outside of this range vhf communication will not be possible relays with other aircraft closer to land could be used but the aircraft will usually change to hf radio and datalink communications instead hf radio can travel as a sky wave which requires ionospheric refraction to 'bounce' the signal off the upper atmosphere and as a short surface/ground wave although this is not really used so can allow transmissions that can go further than the line of sight limitations of vhf vhf has a frequency too high to be affected much by ionospheric attenuation and refraction and therefore will not be able to form a sky wave its frequency is also too high to propagate for any reasonable distances as a ground wave as the attenuation due to obstacles etc is huge even hf radio struggles to propagate as ground waves for our uses so vhf is ever worse there is some diffraction of vhf radio waves around the earth's surface which extends range slightly but it is not a huge effect note the mention of dawn in the question is not necessary vhf radio is not affected by ionospheric refraction which could create a sky wave so dawn/dusk/night does not make a difference exemple 306 Space waves have no reflection by the ionosphere, no surface waves.Space waves have no reflection by the ionosphere, no surface waves.

An aircraft is flying in the skip zone dead space the pilot wishes to ?

Question 178-9 : 1 higher 2 sky 1 lower 2 surface 1 towards the station 2 sky 1 away from the station 2 surface

Refer to figures . hf radio waves are transmitted as surface waves figure part c or sky waves figure part b surface wave propagation exists at frequencies from about 20 khz to about 50 mhz from the upper end of vlf to the lower end of vhf surface waves are created due to diffraction the portion of the wave in contact with the surface of the earth is retarded which results in bending of the wave around the surface of the earth the range of the surface waves is limited due to surface attenuation the wave induces a voltage in the earth which takes energy away from it sky wave propagation exists at frequencies between 2 mhz to 30 mhz from the upper end of mf to the whole hf range sky waves are radio waves that reach the ionosphere an electrically charged layer of the upper atmosphere and are reflected back toward the earth since sky waves are not limited by the curvature of the earth sky wave propagation can be used to communicate beyond the horizon at intercontinental distances for every frequency capable to create sky waves there is an angle between the vertical and the radio wave known as critical angle refer to figure above which total internal refraction occurs and the wave returns to the surface first returning sky wave at angles below critical radio waves pass straight through ionosphere and outer space they do not return on the surface of the earth the distance from the transmitter to the point where the first returning sky wave appears at the surface is known as the skip distance from the point where the surface wave is totally attenuated to the point where the first returning sky wave appears there will be no detectable signal this area is known as dead space exemple 310 (1) higher; (2) sky(1) higher; (2) sky

Imagine an aircraft not equipped with automatic temperature correction what ?

Question 178-10 : Colder temperature reduces your glide path angle warmer temperature reduces your glide path angle temperature has no effect on your glide path angle colder temperature highers your glide path angle

Temperature correction .even with no other errors at all the pressure altimeter will not indicate true altitude height amsl unless the surface temperature and lapse rate of the column of air are those assumed in the calibration in flight from high to low temperature the altimeter would read high .this means that the approach path flown by an aircraft would be shallower than expected with a lower glide path angle exemple 314 Colder temperature reduces your glide path angle.Colder temperature reduces your glide path angle.

What is the maximum theoretical range at which an aircraft flying at 3500 ft ?

Question 178-11 : 87 nm 87 km 74 nm 74 km

Refer to figure .the space wave is the direct line of sight transmission of a radio wave through space because the earth is round vhf communications via space waves are limited by the curvature of the earth as such aircraft at higher altitude and transmission stations at higher altitude have a higher maximum theoretical communication range the equation to calculate maximum theoretical range is maximum theoretical range in nm = 1 23 x h3 + h4 where h3 is the receiver height in feeth4 is the transmitter height in feetcalculating the range for the problem in the question range = 1 23 x 3500 + 126 = 86 6 nm 87 nm exemple 318 87 nm87 nm

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

Question 178-12 : 400 hz blue 400 hz amber 1300 hz blue 3000 hz blue

Admin . 677 exemple 322 400 hz, blue.400 hz, blue.

An rmi indicates aircraft heading and bearing .to convert the rmi bearings of ?

Question 178-13 : Ndb aircraft position .vor beacon position ndb beacon position .vor beacon position ndb beacon position .vor aircraft position ndb aircraft position .vor aircraft position

Admin .application of magnetic variation is at beacon position for a vor .application of magnetic variation is at aircraft position for a ndb exemple 326 Ndb: aircraft position xsxvor: beacon position.Ndb: aircraft position xsxvor: beacon position.

An aircraft is flying on the true track 090° towards a vor station located ?

Question 178-14 : 255° 278° 262° 285°

Admin .application of magnetic variation is at beacon position for a vor so flying 90° true tracks towards a vor means that we are on the 270° inbound radial .270° minus 15° east = 255° m exemple 330 255°.255°.

Given .magnetic heading 280° .vor radial 090° .what bearing should be ?

Question 178-15 : 270° 280° 100° 090°

Admin .for training purpose please use one of the following websites .luizmonteiro learning vor exemple 334 270°.270°.

A vor is sited at position 58°00'n 073°00'w where the magnetic variation ?

Question 178-16 : 212° 208° 360° 180°

Admin .the aircraft is south of the vor and we apply the variation at the beacon it is a vor .the aircraft is on vor radial of 180 + 32 = 212° .declination west > compass best.declination east > compass least exemple 338 212°.212°.

In order to plot a bearing from a vor station a pilot needs to know the ?

Question 178-17 : At the vor at the aircraft location at the half way point between the aircraft and the station at both the vor and aircraft

Admin .the application of magnetic variation is .ndb aircraft position .vor beacon position exemple 342 At the vor.At the vor.

An aircraft dme receiver does not lock on to its own transmissions reflected ?

Question 178-18 : They are not on the receiver frequency dme transmits twin pulses the pulse recurrence rates are varied dme uses the uhf band

Admin .the interrogation and reply frequencies always differ by 63 mhz exemple 346 They are not on the receiver frequency.They are not on the receiver frequency.

A dme is located at msl an aircraft passing vertically above the station at ?

Question 178-19 : 6 nm 7 nm 11 nm 8 nm

Admin .the aircraft is directly overhead the beacon so interrogation pulses will therefore go vertically down to the beacon and the response pulses will go vertically upwards to the aircraft ..dme range = 36000ft.1 nm = 6000ft.dme range = 36000/6000 = 6 nm exemple 350 6 nm.6 nm.

During a flight at fl 210 a pilot does not receive any dme distance indication ?

Question 178-20 : Aircraft is below the 'line of sight' altitude aircraft is circling around the station altitude is too high range of a dme system is always less than 200 nm

Admin .dme distance measuring equipment ground stations transmit within a uhf frequency band of 962 to 1213 mhz because the equipment is uhf the signals transmitted are subject to line of sight restrictions therefore its range varies in direct proportion to the altitude of receiving equipment .generally the reception range of the signals at an altitude of 1 000 feet above ground level agl is about 40 to 45 miles this distance increases with altitude .vhf transmissions follow a line of sight course . 2562 exemple 354 Aircraft is below the 'line of sight' altitude.Aircraft is below the 'line of sight' altitude.

Which of the following will give the most accurate calculation of aircraft ?

Question 178-21 : A dme station sited on the flight route an adf sited on the flight route a vor station sited on the flight route a dme station sited across the flight route

Admin . dme distance measuring equipment .the dme receiver can express groundspeed in knots this value is accurate only if the aircraft is flying directly to or from the station because the dme measures groundspeed by comparing the time lapse between a series of pulses when accurate the groundspeed information allows the pilot to make accurate estimates of time of arrival and accurate checks of aircraft progress exemple 358 A dme station sited on the flight route.A dme station sited on the flight route.

What is the approximate angular coverage of reliable navigation information for ?

Question 178-22 : 1 35° above the horizontal to 5 25° above the horizontal and 8° each side of the localiser centreline 0 45° above the horizontal to 1 75° above the glide path and 8° each side of the localiser centreline 0 7° above and below the glide path and 2 5° each side of the localiser centreline 3° above and below the glide path and 10° each side of the localiser centreline

Admin . 1680.glide slope coverage goes from 0 45 to 1 75 times the glide path angle .3° x 0 45 = 1 35°.3° x 1 75 = 5 25° exemple 362 1.35° above the horizontal to 5.25° above the horizontal and 8° each side of the localiser centreline.1.35° above the horizontal to 5.25° above the horizontal and 8° each side of the localiser centreline.

A vor is sited at position a 45°00'n 010°00'e .an aircraft is located at ?

Question 178-23 : 190° 195° 185° 180°

Admin .the application of magnetic variation is .for a ndb aircraft position .for a vor beacon position . 2563.aircraft is south 180°t of the vor and we have to apply variation at the vor position . variation west magnetic best .180° + 10° = 190° exemple 366 190°.190°.

A dme station is located 1000 feet above msl .an aircraft flying at fl 370 in ?

Question 178-24 : 16 nm 14 nm 15 nm 17 nm

Admin .pythagoras' theorem .dme range² = ground range² + height².dme² = 225 + 36.dme = sqrt 261 .dme = 16 16 nm exemple 370 16 nm.16 nm.

What is the approximate maximum theoretical range at which an aircraft at fl130 ?

Question 178-25 : 180 nm 220 nm 120 nm 150 nm

Admin .1 23* sqrt1024 + sqrt13000 = 179 6 nm . sqrt square root exemple 374 180 nm.180 nm.

In isa conditions what is the maximum theoretical range at which an aircraft at ?

Question 178-26 : 134 nm 158 nm 107 nm 114 nm

Admin .calculate the range using the formula .1 23 x sqrttransmitter height in feet + 1 23 x sqrtreceiver height in feet .1 23* sqrt325 + sqrt8000 = 132 2 nm . sqrt square root exemple 378 134 nm.134 nm.

The principle used in vor bearing measurement is ?

Question 178-27 : Phase comparison envelope matching beat frequency discrimination difference in depth of modulation

The vor encodes azimuth direction from the station as the phase relationship of a reference and a variable signal .the omni directional signal contains a modulated continuous wave mcw and morse code station identifier and usually contains an amplitude modulated am voice channel .the conventional 30 hz reference signal is on a 9960 hz frequency modulated fm subcarrier the variable amplitude modulated am signal is conventionally derived from the lighthouse like rotation of a directional antenna array 30 times per second although older antennas were mechanically rotated current installations scan electronically to achieve an equivalent result with no moving parts when the signal is received in the aircraft the two 30 hz signals are detected and then compared to determine the phase angle between them the phase angle by which the am signal lags the fm subcarrier signal is equal to the direction from the station to the aircraft in degrees from local magnetic north and is called the 'radial ' exemple 382 Phase comparison.Phase comparison.

You are flying along an airway which is 10 nm wide 5 nm either side of the ?

Question 178-28 : 1 5 3 0 4 5 6 0

Admin .apply the 1 in 60 rule.= max distance off route x 60 / range.= 5 x 60/ 100.= 300/100.= 3°.2° = 1 dot.3° = 1 5 dots exemple 386 1.51.5

An airway 10 nm wide is to be defined by two vors each having a resultant ?

Question 178-29 : 105 nm 50 nm 165 nm 210 nm

Admin .tan 5 5 x x = 10 nm.x = 10 / 0 0962 = 103 9 nm .miloszhomik .10 nm wide but 5 to each side so it will be approx 50 nm .. .approximately 50 nm if you consider only the beacon behind you but when you switch to the beacon in front of you the maximum distance apart for the transmitter will be approximately 52 5 + 52 5 = 105 nm exemple 390 105 nm.105 nm.

An aircraft is required to approach a vor via the 104° radial .which of the ?

Question 178-30 : 284° with the to flag showing 284° with the from flag showing 104° with the to flag showing 104° with the from flag showing

Admin .for training purpose please use .luizmonteiro learning vor exemple 394 284° with the to flag showing.284° with the to flag showing.

An aircraft is required to approach a vor station via the 244° radial .in ?

Question 178-31 : 064° with the to flag showing 064° with the from flag showing 244° with the from flag showing 244° with the to flag showing

Admin . 1710.for training purpose .luizmonteiro learning vor exemple 398 064° with the to flag showing.064° with the to flag showing.

What is the maximum theoretical range that an aircraft at fl150 can receive ?

Question 178-32 : 181 nm 220 nm 147 nm 156 nm

1 23* sqrt609 + sqrt15000 = 181 nm . sqrt square root exemple 402 181 nm.181 nm.

For a conventional dme facility 'beacon saturation' will occur whenever the ?

Question 178-33 : 100 200 60 80

Admin .a typical dme transponder can provide distance information to 100 aircraft at a time above this limit the transponder avoids overload by limiting the gain of the receiver replies to weaker more distant interrogations are ignored to lower the transponder load .dme can be used by 300 users at one time the technical term of the dme station when its overloaded and cannot accept more than 100 aircraft is called 'station or beacon saturation' exemple 406 100.100.

The aircraft dme receiver is able to accept replies to its own transmissions ?

Question 178-34 : The time interval between pulse pairs is unique to that particular aircraft transmission frequencies are 63 mhz different for each aircraft pulse pairs are amplitude modulated with the aircraft registration aircraft interrogation signals and transponder responses are 63 mhz removed from each other

Admin .the interrogation and reply frequencies always differ by 63 mhz .the time interval between pulse pairs is unique because the pulse recurrence frequency is randomised exemple 410 The time interval between pulse pairs is unique to that particular aircraft.The time interval between pulse pairs is unique to that particular aircraft.

The aircraft dme receiver cannot lock on to interrogation signals reflected ?

Question 178-35 : Aircraft transmitter and dme ground station are transmitting on different frequencies reflections are subject to doppler frequency shift dme transmits twin pulses dme pulse recurrence rates are varied

Admin .the interrogation pulses are at one frequency 1030 mhz and the reply pulses are at a different frequency 1090 mhz exemple 414 Aircraft transmitter and dme ground station are transmitting on different frequencies.Aircraft transmitter and dme ground station are transmitting on different frequencies.

The design requirements for dme n stipulate that at a range of 100 nm the ?

Question 178-36 : + or 1 5 nm + or 3 nm + or 0 25 nm + or 1 25 nm

Admin .the error of the dme 'n' according to annex 10 should not exceed + 0 25 nm + 1 25% of the distance measured .0 25 + 0 0125 x 100 = 1 5 nm . for installations installed after 1 jan 1989 the total system error should not exceed 0 2 nm for dme 'p' precise exemple 418 + or - 1.5 nm.+ or - 1.5 nm.

In which situation will speed indications on an airborne distance measuring ?

Question 178-37 : When tracking directly towards the station at a range of 100 nm or more when passing abeam the station and within 5 nm of it when overhead the station with no change of heading at transit when tracking directly away from the station at a range of 10 nm

Admin .the dme instrument in the cockpit will not only show your distance to a station but will calculate the rate of movement and display groundspeed .if you are to close you will have a 'slant range' the distance mesured is the from the station to the aircraft and not from your equivalent position on the ground .at long distances this will be minimised . when passing abeam the station and within 5 nm and at a range of 10 nm will not give you the most accurate groundspeed indication . overhead the station will give you a grounspeed indication of zero exemple 422 When tracking directly towards the station at a range of 100 nm or more.When tracking directly towards the station at a range of 100 nm or more.

The time taken for the transmission of an interrogation pulse by a distance ?

Question 178-38 : 158 nm 296 nm 316 nm 186 nm

Admin . 2564.slant range= time 50 micro second /2 x c velocity of light in km/s .slant range= 2000 50 /2 x c.slant range= 975 x 300000.slant range= 292500000.292 500 km > 158 nm .50 micro second is the time taken by the airborne receiver to reply to the ground transponder and you must divide 2000 by 2 because 2000 micro second is the total time taken for a signal to travel and come back exemple 426 158 nm.158 nm.

The reason why pre take off holding areas are sometimes further from the active ?

Question 178-39 : Aircraft manoeuvring near the runway may disturb guidance signals heavy precipitation may disturb guidance signals to increase distance from the runway during offset approach operations to increase aircraft separation in very reduced visibility conditions

exemple 430 Aircraft manoeuvring near the runway may disturb guidance signals.Aircraft manoeuvring near the runway may disturb guidance signals.

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

Question 178-40 : May receive false course indications only glide path information is available will receive signals without identification coding can expect signals to give correct indications

Admin .false glideslope signals may exist outside the published ils coverage angle and in the area of the localizer back course approach which can cause the glideslope flag alarm to disappear and present unreliable glideslope information exemple 434 May receive false course indications.May receive false course indications.

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