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Question 206-1 : 'fruiting' is caused by ? [ Exam pilot ]

Aeroplane at range responding to interrogations from another atc radar station

exemple 306 Aeroplane at range responding to interrogations from another atc radar station.

Question 206-2 : The carrier frequency of the ssr atc reply transmission air to ground is ?

1090 mhz + or 3 mhz

Admin .icao annex 10 volume 4 chapter 3 .3 1 1 2 reply carrler frequency air to ground .3 1 1 2 1 the carrier frequency of the reply transmission shall be 1 090 mhz .3 1 1 2 2 the frequency tolerance shall be plus or minus 3 mhz exemple 310 1090 mhz + or - 3 mhz.

Question 206-3 : A mode s transponder receives among other pulses a long p4 pulse from an interrogator what does this mean ?

The interrogator transmits a mode a/c/s all call

Admin .short p4 pulse mode a/c only all call .long p4 pulse mode a/c/s all call exemple 314 The interrogator transmits a mode a/c/s all call.

Question 206-4 : A mode a/c transponder receives a p2 pulse from which the amplitude is smaller than that of the p1 and p3 pulse what is the reason ?

The transponder is located in the direction of the main lobe of the interrogator antenna

Admin . 2621 exemple 318 The transponder is located in the direction of the main lobe of the interrogator antenna.

Question 206-5 : A mode a/c transponder receives a p2 pulse from which the amplitude is larger than that of the p1 and p3 pulse what is the reason ?

The transponder is located in the direction of one of the side lobes of the interrogator antenna

Admin . 2621 exemple 322 The transponder is located in the direction of one of the side lobes of the interrogator antenna.

Question 206-6 : What determines the operating mode a or c of the ssr transponder ?

The time interval between the pulses p1 and p3

Admin . 2621. 1666 exemple 326 The time interval between the pulses p1 and p3.

Question 206-7 : What is one of the differences between a mode a/c/s all call and a mode a/c only all call ?

The length of the pulse p4

Admin .short p4 pulse mode a/c only all call .long p4 pulse mode a/c/s all call .the time interval between the pulses p1 and p3 determines the operating mode a or c of the ssr transponder exemple 330 The length of the pulse p4.

Question 206-8 : The time interval between the interrogating pulses p1 and p3 in mode c is ?

21 us

Admin . 1666 exemple 334 21 us.

Question 206-9 : The time interval between the interrogating pulses p1 and p3 in mode a is ?

8 us

Admin . 1666 exemple 338 8 us.

Question 206-10 : Ssr transponder .mode s provides ?

25 possible reply forms

exemple 342 25 possible reply forms.

Question 206-11 : The equipment that uses the pulse modulation technique is the ?

Radar

Admin .pulse modulation a modulation form used in radar by transmitting short pulses followed by larger interruptions exemple 346 Radar.

Question 206-12 : Ssr transponder .in intermode a 'short' p4 pulse makes it possible to perform a call ?

A/c

exemple 350 A/c.

Question 206-13 : Ssr transponder .a mode a/c transponder ?

Responds to mode s interrogations but can not send data

exemple 354 Responds to mode s interrogations but can not send data.

Question 206-14 : The main advantage of ssr over a primary radar is ?

Air traffic control ssr systems can interrogate the transponder of an aircraft and obtain answers

exemple 358 Air traffic control ssr systems can interrogate the transponder of an aircraft and obtain answers.

Question 206-15 : What is the accuracy of mode s altitude reporting ?

25 feet

Admin .mode s can provide enhanced vertical tracking using a 25 feet altitude increment exemple 362 25 feet.

Question 206-16 : To increase the maximum range of a radar it is necessary to ?

Decrease the recurrence frequency and to increase the wavelength

exemple 366 Decrease the recurrence frequency and to increase the wavelength.

Question 206-17 : Ssr transponder .with the 'enhanced' mode s additional aircraft parameters can be downloaded by the atc ?

Ias vertical rate roll angle

Ecqb04 november 2017 ..enhanced mode s surveillance consists of the extraction of additional aircraft parameters known as downlink aircraft parameters dap consisting of . magnetic heading . indicated airspeed . mach number . vertical rate . roll angle . track angle rate . true track angle . ground speed . selected altitude .note tas is provided if track angle rate is not available exemple 370 Ias, vertical rate, roll angle.

Question 206-18 : An antenna is defined as a ?

Wave type transducer for the process of converting a line ac into a free electromagnetic wave

Ecqb04 november 2017 exemple 374 Wave-type transducer for the process of converting a line ac into a free electromagnetic wave.

Question 206-19 : Ssr transponder .what is involved in enhanced downlink . tas. ground speed. eas. magnetic heading. course. flight level ?

Tas ground speed magnetic heading

Ecqb04 november 2017 ..enhanced mode s surveillance consists of the extraction of additional aircraft parameters known as downlink aircraft parameters dap consisting of . magnetic heading . indicated airspeed . mach number . vertical rate . roll angle . track angle rate . true track angle . ground speed . selected altitude .note tas is provided if track angle rate is not available exemple 378 Tas, ground speed, magnetic heading.

Question 206-20 : Ssr transponder .a mode s surveillance protocols implicitly use the principle of selective addressing the advantage of mode s for a ssr over a primary radar is ?

It permits unambiguous aircraft identification

Ecqb04 november 2017 exemple 382 It permits unambiguous aircraft identification.

Question 206-21 : A vertical aerial antenna needs the receiver to be oriented in the plane to receive the em wave in the plane ?

Vertical vertical

Ecqb04 november 2017 ..an electromagnetic wave em consists of an oscillating electric field e and an oscillating magnetic field h which propagates at the speed of light .the electric field is parallel to the wire and the magnetic field is perpendicular to it .the e and h fields are perpendicular to each other exemple 386 Vertical, vertical.

Question 206-22 : Which of the following statements about a primary radar are correct .1 target size will influence the maximum range.2 detection of targets in the area close to the radar will be difficult.3 precipitation may reduce the useful range.the combination that regroups all of the correct statements is ?

1 2 3

Ecqb04 november 2017 exemple 390 1, 2, 3.

Question 206-23 : Ssr transponder mode s enhanced surveillance .the controller's information is improved by providing actual aircraft derived data such as ?

Magnetic heading indicated airspeed vertical rate and selected altitude

Ecqb04 november 2017 ..pressure altitude flight level flight number or aircraft registration and ground speed are basic data send by a mode c or s transponder enhanced surveillance consists of the extraction of additional aircraft parameters such as magnetic heading indicated airspeed vertical rate and selected altitude exemple 394 Magnetic heading, indicated airspeed, vertical rate and selected altitude.

Question 206-24 : Ssr transponder mode s enhanced surveillance .automatic extraction of an aircraft's parameters and their presentation to the controller will reduce their ?

Radio telephony workload and will free them to concentrate on ensuring the safe and efficient passage of air traffic

Ecqb04 november 2017 ..with enhanced surveillance mode s the controller's information is improved by providing actual aircraft derived data such as magnetic heading indicated airspeed vertical rate and selected altitude the automatic extraction of an aircraft's parameters and their presentation to the controller will reduce their r/t workload and will free them to concentrate on ensuring the safe and efficient passage of air traffic .the reduction in radio telephony between the air traffic controllers and the pilots will reduce pilot workload and remove a potential source of error exemple 398 Radio-telephony workload and will free them to concentrate on ensuring the safe and efficient passage of air traffic.

Question 206-25 : Ssr transponder mode s enhanced surveillance .the reduction in radio telephony between the air traffic controllers and the pilots will ?

Reduce pilot workload and remove a potential source of error

Ecqb04 november 2017 ..with enhanced surveillance mode s the controller's information is improved by providing actual aircraft derived data such as magnetic heading indicated airspeed vertical rate and selected altitude the automatic extraction of an aircraft's parameters and their presentation to the controller will reduce their r/t workload and will free them to concentrate on ensuring the safe and efficient passage of air traffic .the reduction in radio telephony between the air traffic controllers and the pilots will reduce pilot workload and remove a potential source of error exemple 402 Reduce pilot workload and remove a potential source of error.

Question 206-26 : Airborne weather radar awr should be used with extreme caution when on the ground because ?

It can hurt the ground staff

Ecqb04 november 2017 exemple 406 It can hurt the ground staff.

Question 206-27 : The main disadvantage of using an airborne weather radar awr on the ground is ?

Shf waves it emits can damage tissues of the people on whom it radiates

Ecqb04 november 2017 exemple 410 Shf waves it emits can damage tissues of the people on whom it radiates.

Question 206-28 : Which of the following is a complete list of airborne weather radar antenna stabilisation axes ?

Roll and pitch

The airborne weather radar awr is normally mounted in the nose section and the centre postion is aligned with the fore aft axis of the aircraft the aerial regardless of the type is fitted on a gimbal system that stabilises the aerial with the horizon both in roll and pitch directions therefore regardless of the attitude changes of the aircraft the antenna is kept in the same attitude relative to the horizon this is to ensure that the radar picture is not distorted or lost during manoeuvres of the aeroplane exemple 414 Roll and pitch

Question 206-29 : In an airborne weather radar that has a colour cathode display increasing severity of rain and turbulence is generally shown by a change of colour from… ?

Green to yellow red magenta

Airborne weather radardepending on the returning echoes the reflectivity of the area defines the amount of water droplets present therefore the differing intensity of expected precipitation is presented to the pilot with colour codes the painted colours dependent on the water concentration are as follows colourwater concentrationexpected turbulencegreenlightnone or lightyellowmoderatelightredheavymediu mor severemagentaheavy or icesevere exemple 418 Green to yellow, red, magenta.

Question 206-30 : Considering a primary radar system what kind of aerials are used ?

One directional antenna both for transmitting and for receiving

A primary radar is a conventional radar sensor that illuminates a large portion of space with an electromagnetic wave and receives back the reflected waves from targets within that space .primary radar is used to detect aircraft not equipped with a secondary radar transponder .in order to achieve this function the primary radar uses a directional antenna .a directional antenna or beam antenna is an antenna which radiates or receives greater power in specific directions allowing increased performance and reduced interference from unwanted sources ideally to use for air traffic control services to serve a large number of aircrafts exemple 422 One directional antenna both for transmitting and for receiving.

Question 206-31 : What information may be displayed on an atc radar screen connected only to a primary radar system ?

Aircraft position only

Refer to figure .learning objective 062 03 02 01 01 explain that primary radar provides bearing and distance of targets .primary radar is the simplest type of radar it refers to a system which emits pulses of electromagnetic energy then waits for any of those pulses to return and if/when they do it measures the time between emitting the pulse and receiving the reflected pulse which it can then use to calculate the distance from the target as the electromagnetic waves all travel at the speed of light .it does this whilst scanning the sky from side to side so each pulse targets a different area of the sky horizontally and by sending pulses many hundreds of times per second the radar can scan the region and get both a bearing and a distance to each target this can then be plotted on a display for the radar operator to see .with primary radar you can therefore only see locations of targets and can extrapolate their movements over time to get a rough idea of their speed if the operator is skilled .other radar systems can provide more information than this ssr secondary surveillance radar which use a different method of radar operation exemple 426 Aircraft position only.

Question 206-32 : Airborne weather radar has been primarily developed to detect ?

The kinds of intense precipitation which are usually accompanied by turbulence

Learning objective 062 03 03 01 02 state that modern weather radars employ frequencies that give wavelengths of about 3 cm that reflect best on wet hailstones .airborne weather radars awrs have been created so that the pulses the emit reflect best off objects that are the same size as large water droplets hailstones one of the primary tasks of an awr system is to detect upcoming turbulence and bad weather so that the pilots can take necessary precautions or avoiding action .the largest areas of turbulence come from cumulonimbus cb clouds which contain large droplets of water ice crystals and hail stones modern awrs are set up to have a wavelength of approximately 3cm so they bounce off these types of precipitation the most the radars have been tuned this way to make sure that more radar returns means that there is a higher chance of turbulence in that area usually the bigger the hail/droplets the worse the turbulence .the radar pulses will always reflect off wet hail and large water droplets better than they will off smaller water droplets dry hail and ice crystals exemple 430 The kinds of intense precipitation which are usually accompanied by turbulence.

Question 206-33 : An airborne transponder can provide coded reply signals in response to interrogation signals from ?

Ground secondary surveillance radar and from aircraft equipped with tcas

A transponder xpdr is a receiver/transmitter which will generate a response in the form of a coded pulse train upon proper interrogation the interrogation and reply being on different frequencies an advantage of the transponder is that it is capable of communicating with not only ssr equipment but also other airborne transponders whereby exhanging flight parameters aids the traffic collision avoidance system tcas between flying aircraft .civil aircraft may be equipped with transponders capable of operating in different modes .. mode a equipment transmits an identifying code only . mode c equipment enables the atco to see the aircraft altitude or flight level automatically . mode s equipment has altitude capability and also permits data exchange exemple 434 Ground secondary surveillance radar and from aircraft equipped with tcas.

Question 206-34 : A mode c transponder is able to report the pressure altitude in ?

100 ft increments

Vertical performance.mode c provides pressure altitude information in addition to identification and position information compared to mode a the transponder message is reported in 100 feet increments which should be considered in terms of vertical separaction by atc .mode s has significantly better performance compared to mode c in terms of updating controller with altitude data the altitude may be reported with an accuracy of 25 feet exemple 438 100 ft increments.

Question 206-35 : Why should airborne weather radar awr systems be used with extreme caution when on the ground ?

People could be exposed to super high frequency shf radiation which if absorbed in large enough amounts can lead to tissue damage

Avoid weather radar awr operation when personnel are within the area normally enclosed by the aircraft nose radome these radars can be the most dangerous critters in the cockpit awr work on super high freqencies shf to do what they do and without proper care that energy can be hazardous to you and others around the airplane i e tissues getting damaged exemple 442 People could be exposed to super high frequency (shf) radiation which, if absorbed in large enough amounts, can lead to tissue damage.

Question 206-36 : Which data can be determined and displayed by atc secondary surveillance radar ssr and primary surveillance radar psr systems ?

Psr target range and bearing ssr target range and bearing aircraft identification codes aircraft altitude selective addressing and full two way data link

Primary surveillance radar psr the radar antenna rotates usually at 5 12 rpm emits a pulse of radio wave .upon reaching an aircraft or other object the wave is reflected and some of the energy is returned to the antenna .the psr output data uses polar coordinate system it provides range and bearing of the targets found in respect of the antenna position .note that the range is the slant distance from the antenna and not the horizontal distance .the range is determined by the time difference of the emitted and received pulse the speed of propagation is the speed of light and the bearing is obtained from the antenna azimuth .the rotation speed of the antenna is usually between 5 and 12 rpm .the antenna radiation patern is a narrow beam when seen from above and whith some approximation can be considered as a trapezium if seen from the side .secondary surveillance radar ssr requires an airborne transponder which responds to the receipt of a pulse from a ground based antenna by transmitting a return signal .because the transponder transmits a much stronger signal than that which is reflected off an aircraft in primary radar systems .reater range and reliability can be achieved with secondary radar and cheaper and more efficient ground equipment can be used .additionally information such as altitude and a code can be added to the returned signal from the transponder which is then displayed on the operator’s screen .in mode a the aircraft's transponder provides positive aircraft identification by transmitting a four digit code to the ground station .the code system is octal that is each of the code digits may be any of the numbers 0 7 .there are thus 4096 possible four digit codes .in mode c the aircraft's altitude derived from on board instruments is transmitted to the ground station in addition to the identity .aircraft equipped with transponders supporting mode s are assigned a permanent identification which can be selectively addressed by the ground radar .this reduces problems of garbling between ssr returns from aircraft in close proximity .mode s also offers a wider range of data to be transmitted including potentially an uplink of data from the ground station to the aircraft exemple 446 Psr: target range and bearing. ssr: target range and bearing, aircraft identification codes, aircraft altitude, selective addressing, and full two-way data link.

Question 206-37 : The main factor which determines the minimum range that can be measured by a pulsed radar is ?

Pulse length

Maximum theoretical range.pulse repetition frequency prf is the number of occurrences pulses each second the prf has a large significance on maximum range depending on how far the radar wishes to search for objects and what the visible range is the pulse repetition interval has to be set in a way to always allow the pulse to reach the range limits and return .the maximum theoretical unambiguous range is calculate by the formula .. maximum range km = 300 000 ÷ prf × 2 ..in the above formula the range is given in kilometres and the prf is in pps the formula includes '300 000' which represents the number of km the light travels every second speed of light ..minimum theoretical range.pulse length or width is the measurement taken from the leading to trailing edge of a pulse and is a good indicator of the amount of power contained within the pulse generally longer pulses emitted from a radar return more power the minimum range capability of a radar is determined primarily by the pulse length or width .. minimum range km = 300 000 x pulse length / 2 exemple 450 Pulse length.

Question 206-38 : The airborne weather radar ?

May receive no reflections from a thunderstorm in an area behind a heavy rain shower

Refer to figure .weather attenuation.the weather radar display depends on signal returns the more intense the precipitation the less distance the radar can see through therefore when the radar echo is unable to make the two way trip through heavy precipitation a 'shadowing' effect occurs .the stronger the rainstorm the more radar energy will be scattered by weather attenuation in simple words radar attenuation or shadowing is simply the absorption or reflection of radar signals as the radar pulse penetrates an area of precipitation preventing that radar from detecting any additional cells that lie behind the first storm .. the awr is blind to whatever conditions may be lurking behind the thunderstorm in the area where the shadowing occurs conditions are unknown exemple 454 May receive no reflections from a thunderstorm in an area behind a heavy rain shower.

Question 206-39 : What determines the operating mode a or c of the ssr transponder ?

The time interval between the pulses p1 and p3

A secondary surveillance radar ssr system uses transmitters/receivers interrogators and transponders a pulse coded interrogation message is sent from the ground to the aircraft the transponder responds in accordance with the pulse coded interrogation in the form of a pulse train that is a series of pulses which carry the appropriate information the transmissions are achieved in the uhf band where all ground interrogation pulses are processed at a 1 030 mhz carrier frequency and all transponder responses are completed on the 1 090 mhz carrier channel the two main modes of operation excluding mode s are mode a an interrogation to identify an aircraft mode c an interrogation to obtain an automatic height read out of an aircraft three pulses p1 p2 and p3 are always transmitted to differentiate between interrogations the spacing between p1 and p2 is fixed at 2 s the spacing between p1 and p3 is 8 s for a mode a and 21 s for a mode c interrogation the transponder detects the time interval between the pulses p1 and p3 which determines the mode of interrogation exemple 458 The time interval between the pulses p1 and p3.

Question 206-40 : Airborne weather radar systems use a wavelength of approximately 3 cm in order to ?

Detect larger water droplets

Typically the radar antenna is located in the nose of the aircraft signals from the antenna are processed by a computer and presented on a screen which may be viewed by the pilots droplet size is a good indicator of strong updrafts within cumulonimbus clouds and associated turbulence and is indicated on the screen by patterns colour coded for intensity it needs to be noted that the frequency band of the radio waves x band is selected not to detect any cloud small precipitation such as drizzle fog or wind as the droplets are too little or don’t exist some airborne weather radar systems may also be able to predict the presence of wind shear .weather radars send directional pulses of microwave radiation on the order of a microsecond long using a cavity magnetron or klystron tube connected by a waveguide to a parabolic antenna the wavelengths of 1 – 10 cm are approximately ten times the diameter of the droplets or ice particles of interest because rayleigh scattering occurs at these frequencies this means that part of the energy of each pulse will bounce off these small particles back in the direction of the radar station .shorter wavelengths are useful for smaller particles but the signal is more quickly attenuated thus 10 cm s band radar is preferred but is more expensive than a 5 cm c band system 3 cm x band radar is used only for short range units and 1 cm ka band weather radar is used only for research on small particle phenomena such as drizzle and fog w band weather radar systems have seen limited university use but due to quicker attenuation most data are not operational .radar pulses spread out as they move away from the radar station thus the volume of air that a radar pulse is traversing is larger for areas farther away from the station and smaller for nearby areas decreasing resolution at far distances at the end of a 150 – 200 km sounding range the volume of air scanned by a single pulse might be on the order of a cubic kilometer this is called the pulse volume exemple 462 Detect larger water droplets.


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