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The main advantage of ssr over a primary radar is ? [ Answer reports ]

Question 193-1 : Air traffic control ssr systems can interrogate the transponder of an aircraft and obtain answers air traffic control ssr systems continually interrogating the aircraft in range the follow up is uninterrupted air traffic control ssr systems can respond to an aircraft interrogation and provide the required information ssr has the ability to discriminate mobile targets moving target indicators mti which eliminates returns and permits to track more aircraft

exemple 293 Air traffic control ssr systems can interrogate the transponder of an aircraft and obtain answers.Air traffic control ssr systems can interrogate the transponder of an aircraft and obtain answers.

What is the accuracy of mode s altitude reporting ?

Question 193-2 : 25 feet 200 feet 100 feet 50 feet

Admin .mode s can provide enhanced vertical tracking using a 25 feet altitude increment exemple 297 25 feet.25 feet.

To increase the maximum range of a radar it is necessary to ?

Question 193-3 : Decrease the recurrence frequency and to increase the wavelength decreases the recurrence frequency and the wavelength increase the recurrence frequency and the wavelength increase the recurrence frequency and to decrease the wavelength

exemple 301 Decrease the recurrence frequency and to increase the wavelength.Decrease the recurrence frequency and to increase the wavelength.

Ssr transponder .with the 'enhanced' mode s additional aircraft parameters can ?

Question 193-4 : Ias vertical rate roll angle angle of attack pitch angle ground speed fuel remaining oat cross track error usable fuel pitch 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 305 Ias, vertical rate, roll angle.Ias, vertical rate, roll angle.

An antenna is defined as a ?

Question 193-5 : Wave type transducer for the process of converting a line ac into a free electromagnetic wave transformer for the process of converting ac into a radio wave device used for the purpose of receiving a free electromagnetic radio wave and converting it into an audible frequency wave type transducer for the process of converting a dc into a free electromagnetic wave

Ecqb04 november 2017 exemple 309 Wave-type transducer for the process of converting a line ac into a free electromagnetic wave.Wave-type transducer for the process of converting a line ac into a free electromagnetic wave.

Ssr transponder .what is involved in enhanced downlink . tas. ground speed. ?

Question 193-6 : Tas ground speed magnetic heading tas eas flight level ground speed magnetic heading course eas course flight level

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 313 Tas, ground speed, magnetic heading.Tas, ground speed, magnetic heading.

Ssr transponder .a mode s surveillance protocols implicitly use the principle ?

Question 193-7 : It permits unambiguous aircraft identification the range does not depend on transmitter power there is no interaction with the air or space segment in the event of an ssr failure it can act as a primary radar

Ecqb04 november 2017 exemple 317 It permits unambiguous aircraft identification.It permits unambiguous aircraft identification.

A vertical aerial antenna needs the receiver to be oriented in the plane to ?

Question 193-8 : Vertical vertical horizontal vertical horizontal horizontal vertical horizontal

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 321 Vertical, vertical.Vertical, vertical.

Which of the following statements about a primary radar are correct .1 target ?

Question 193-9 : 1 2 3 1 3 2 3 1 2

Ecqb04 november 2017 exemple 325 1, 2, 3.1, 2, 3.

Ssr transponder mode s enhanced surveillance .the controller's information ?

Question 193-10 : Magnetic heading indicated airspeed vertical rate and selected altitude landing mass aircraft turbulence category computed approach speed magnetic heading altitude and identification pressure altitude flight level flight number or aircraft registration ground speed

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 329 Magnetic heading, indicated airspeed, vertical rate and selected altitude.Magnetic heading, indicated airspeed, vertical rate and selected altitude.

Ssr transponder mode s enhanced surveillance .automatic extraction of an ?

Question 193-11 : Radio telephony workload and will free them to concentrate on ensuring the safe and efficient passage of air traffic attention and may lead to routine errors awareness of the situation and may lead to interpretation errors workload but will increase radio telephony exchanges

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

Ssr transponder mode s enhanced surveillance .the reduction in radio ?

Question 193-12 : Reduce pilot workload and remove a potential source of error reduce pilot awareness of the situation and may lead to interpretation errors increase attention but may lead to routine errors reduce the static interferences experienced by gps receivers

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 337 Reduce pilot workload and remove a potential source of error.Reduce pilot workload and remove a potential source of error.

Airborne weather radar awr should be used with extreme caution when on the ?

Question 193-13 : It can hurt the ground staff it may interfere with the alignment of the inertial reference system it can disrupt communication with the tower it can disrupt the airport's radio navigation systems

Ecqb04 november 2017 exemple 341 It can hurt the ground staff.It can hurt the ground staff.

The main disadvantage of using an airborne weather radar awr on the ground is ?

Question 193-14 : Shf waves it emits can damage tissues of the people on whom it radiates reflections on ground and buildings can overheat the radar and switch it off momentarily reflections on ground and buildings are very strong and prevent to see potentially dangerous phenomena when align for take off its antenna can be damaged while taxiing especially on rough runway and taxiway

Ecqb04 november 2017 exemple 345 Shf waves it emits can damage tissues of the people on whom it radiates.Shf waves it emits can damage tissues of the people on whom it radiates.

Which of the following is a complete list of airborne weather radar antenna ?

Question 193-15 : Roll and pitch pitch and yaw roll and yaw roll pitch and yaw

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 349 Roll and pitchRoll and pitch

In an airborne weather radar that has a colour cathode display increasing ?

Question 193-16 : Green to yellow red magenta yellow to orange red green to red black yellow to amber blue

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 353 Green to yellow, red, magenta.Green to yellow, red, magenta.

Considering a primary radar system what kind of aerials are used ?

Question 193-17 : One directional antenna both for transmitting and for receiving an omnidirectional antenna for transmitting and a directional antenna for receiving a directional antenna for transmitting and an omnidirectional antenna for receiving one directional antenna for transmitting and one 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 357 One directional antenna both for transmitting and for receiving.One directional antenna both for transmitting and for receiving.

What information may be displayed on an atc radar screen connected only to a ?

Question 193-18 : Aircraft position only aircraft altitude aircraft position and ssr code aircraft position ssr code and altitude

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 361 Aircraft position only.Aircraft position only.

Airborne weather radar has been primarily developed to detect ?

Question 193-19 : The kinds of intense precipitation which are usually accompanied by turbulence all kinds of frozen precipitation such as hail snow and graupel areas of wind shear and severe aircraft icing areas of severe clear air 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 365 The kinds of intense precipitation which are usually accompanied by turbulence.The kinds of intense precipitation which are usually accompanied by turbulence.

An airborne transponder can provide coded reply signals in response to ?

Question 193-20 : Ground secondary surveillance radar and from aircraft equipped with tcas primary ground radar and from aircraft equipped with a transponder ground secondary surveillance radar and from aircraft equipped with a mode a and c transponder ground secondary surveillance radar and from primary ground radar

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 369 Ground secondary surveillance radar and from aircraft equipped with tcas.Ground secondary surveillance radar and from aircraft equipped with tcas.

A mode c transponder is able to report the pressure altitude in ?

Question 193-21 : 100 ft increments 100 m increments 50 m increments 25 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 373 100 ft increments.100 ft increments.

Why should airborne weather radar awr systems be used with extreme caution when ?

Question 193-22 : People could be exposed to super high frequency shf radiation which if absorbed in large enough amounts can lead to tissue damage the radar system may overheat and shut down due to the intensity of the returns from the ground buildings and surrounding terrain the radar antenna can be easily damaged during ground taxi manoeuvres especially on uneven taxiways the intense returns from the ground and surrounding terrain will not allow accurate identification of potentially hazardous weather when lined up for departure

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

Which data can be determined and displayed by atc secondary surveillance radar ?

Question 193-23 : Psr target range and bearing ssr target range and bearing aircraft identification codes aircraft altitude selective addressing and full two way data link psr target range bearing and aircraft altitude ssr target range and bearing aircraft identification codes aircraft height selective addressing and full two way data link psr target range ssr target range and bearing aircraft altitude and height selective addressing and full two way data link psr target range bearing and aircraft identification ssr 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 381 Psr: target range and bearing. ssr: target range and bearing, aircraft identification codes, aircraft altitude, selective addressing, and full two-way data link.Psr: target range and bearing. ssr: target range and bearing, aircraft identification codes, aircraft altitude, selective addressing, and full two-way data link.

The main factor which determines the minimum range that can be measured by a ?

Question 193-24 : Pulse length pulse amplitude pulse frequency pulse repetition rate

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 385 Pulse length.Pulse length.

The airborne weather radar ?

Question 193-25 : May receive no reflections from a thunderstorm in an area behind a heavy rain shower uses circular polarisation in order to reduce echoes of heavy showers has a second transmitter working on a lower frequency in order to penetrate rain showers has the possibility to detect clear air turbulence behind a thunder storm by measuring phase differences caused by the doppler effect

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

What determines the operating mode a or c of the ssr transponder ?

Question 193-26 : The time interval between the pulses p1 and p3 the position of the spi pulse the difference in amplitude of the pulses p1/p3 and p2 the travel time of the pulses transmitted by the interrogator

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 393 The time interval between the pulses p1 and p3.The time interval between the pulses p1 and p3.

Airborne weather radar systems use a wavelength of approximately 3 cm in order ?

Question 193-27 : Detect larger water droplets obtain optimum use of the cosecant squared beam transmit at a higher pulse repetition frequency for extended range detect small as well as large cloud formations

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 397 Detect larger water droplets.Detect larger water droplets.

What beam is used in the mapping mode of an airborne weather radar that can ?

Question 193-28 : A cosecant squared beam effective up to a maximum of 50 nm to 60 nm a cosecant squared beam effective up to a range of 150 nm a pencil beam effective up to a maximum range of 60 nm a pencil beam effective up to a range of 150 nm

The radar can has two modes weather and mapping the weather beam is used for detecting clouds and is a conical pencil beam with a width of 5 degrees and the mapping is for ground features and uses a fan shaped or cosecant squared beam .the directional properties of the radar produce side lobes one side lobe goes vertically down to the ground and is received back by the weather radar receiver this received signal produces a height ring on the display the ring indicates that the radar is working and appears at the approximate height of the aeroplane above the gound an aeroplane flying at 12000ft will have a permanent return at approximately 2nm .weather radars produce a wide fan shaped beam cosecant square beam by placing parasitic elements in front of the radar dish to deflect the beam it is also referred to as the spoil beam the cosecant square beam provides a wider coverage than the conical beam at short range and its transmission pattern has the effect of compensating for range by sending more power to the top part of the beam which hits more distant objects the cosec beam works out to between 60nm and 150nm depending on type this is probably an old question that’s why the correct answer is from 50nm to 60 nm only beyond that range there is not enough power in the beam to produce reasonable returns so the more concentrated conical beam should be used instead in the weather mode the radar display of ground returns does not always look like the terrain would look like on a map hills can cause 'shadowing' at low altitude masking the terrain behind them and giving a false impression of water in arctic regions returns from ice can mask the true shape of the coastline exemple 401 A cosecant squared beam effective up to a maximum of 50 nm to 60 nm.A cosecant squared beam effective up to a maximum of 50 nm to 60 nm.

Ground secondary surveillance radar ssr equipment incorporates a transmitter ?

Question 193-29 : Transmits on 1030 mhz and receives on 1090 mhz transmits on 1090 mhz and receives on 1030 mhz transmits and receives on 1030 mhz transmits and receives on 1090 mhz

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 .. . ground transmits on 1030 mhz and receives from aircraft on 1090 mhz exemple 405 Transmits on 1030 mhz and receives on 1090 mhz.Transmits on 1030 mhz and receives on 1090 mhz.

Ignoring pulse length the maximum pulse repetition frequency prf that can be ?

Question 193-30 : 405 pps 810 pps 782 pps 308 pps

Prf pulse recurrence frequency is the number of pulses trasmitted in a second . .prf is one of the main factors that determine the maximum theoretical unambiguous range of a pulse radar . .the trasmitter must remain silent while the receiver is listening for echoes . .if the design maximum range is 200nm the receiver must be allowed to listen for the period of time fro when a pulse has been trasmitted untill it can go to 200nm and than return . .that is a round trip of 400 nm which would require a longer silent period than a radar whit a range of 100nm where the pulses have to travel only 200nm . .therefore we can say that a lower prf enables a longer maximum theoretical range max therorical range is inversly proportional to the prf .the following formula may be used to calculate the max theoretical unambiguous range .range in km = 300 000 ÷ prf x 2 or if we need to find the required prf based on a specific unambiguous range needed we can rearrange the formula . .prf = 300 000 ÷ range in km x 2 .in our case we can apply the second one . .1 nm = 1 852 km so . .200 x 1 852 = 370 4 km.prf = 300 000 ÷ 370 4 x 2 . .prf = 404 97 pps = approx 405 pps exemple 409 405 pps.405 pps.

To double the effective range of a primary radar the power output must be ?

Question 193-31 : 16 8 2 4

Primary surveillance radar psr works on the echo principle that uses strong transmitted signals at a known time these signals reflect from objects and the echoes are detected psr theoretical range depends among others on the power output of the radar transmitter .. range nm =4 power w . if we double the range the power output required increases by 16 exemple 413 16.16.

The prime factor in determining the maximum unambiguous range of a primary ?

Question 193-32 : Pulse repetition frequency size of the parabolic receiver aerial power output height of the transmitter above the ground

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 .. 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 .note the minimum detection range of a pulse radar is determined primarily by the pulse length/width exemple 417 Pulse repetition frequency.Pulse repetition frequency.

Airborne weather radars are generally based on the use of ?

Question 193-33 : Primary radar in the shf band secondary radar in the vhf band secondary radar in the shf band primary radar in the uhf band

Airborne weather radar awr is a primary radar system that is fitted to an aeroplane the selected frequency for awr is in the shf band and is 9 375 ghz this has an associated wavelength of 3 2 cm awr must be optimised not to detect very small particles such as thin fog but to accurately identify rain particles in storms .. too small wavelengths will result in reflection from very small particles larger wavelengths result in the waves bending around particles of interest exemple 421 Primary radar in the shf band.Primary radar in the shf band.

Which of the following types of radar equipment operate by means of the pulse ?

Question 193-34 : 1 2 3 and 4 1 2 and 4 only 2 3 and 4 only 2 and 4 only

The pulse technique works by the transmission of pulse modulated signals the pulses are short interval high energy electromagnetic emissions this method is used by .. distance measuring equipment dme interrogator/transponder principle. secondary surveillance radar ssr interrogator/transponder principle. atc area or terminal surveillance radar echo / reflection principle . airport surface movement radar echo/reflection principle. airborne weather radar awr echo principle exemple 425 1, 2, 3 and 41, 2, 3 and 4

Which of the following phenomena is least likely to be detected by radar ?

Question 193-35 : Clear air turbulence wet snow and turbulence in cloud that has precipitation turbulence in cloud that has precipitation precipitation

Conventional weather radar cannot detect wind speed or turbulence directly it only detects solid and liquid objects above a threshold size the most turbulent areas of thunderstorms are also those areas that contain the most water and ice note that the areas in which the concentration of droplets decreases rapidly which are marked on the radar screen by a sharp fall in signal intensity are normally areas in which the most severe turbulence can be encountered these are areas in which the strong up going air currents are in close proximity to downward flowing currents and there is a strong risk of severe vertical wind shear these areas will be identified on the radar screen by a rapid change in appearance of the cloud return steep change in colors of the return steep color gradient if you identify this area on your radar screen avoid that area .* green light precipitation slight turbolence.* yellow or amber medium precipitation light turbolence.* red heavy precipitation medium to severe turbolence.* magenta extremely high precipitation severe turbolence.so the weather radar is merely detecting the presence of water it is the pilot interpreting the picture who is really detecting the turbulence .clear air turbulence cat does not have condensated water in it and is therefore undetectable by conventional radar there are systems such as lidar that can detect cat but they generally not installed on aircraft

What equipment works on the interrogator/transponder principle ?

Question 193-36 : Secondary surveillance radar ssr airborne weather radar awr aerodrome surface movement radar global positioning system gps

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 exemple 433 Secondary surveillance radar (ssr)Secondary surveillance radar (ssr)

If the airborne weather radar system is fitted with an auto tilt function what ?

Question 193-37 : Based on the altitude of the aircraft to tilt fully down when taxiing to reduce the possibility of injury to ground personnel to track the areas with the greatest intensity of precipitation based on the attitude of the aircraft

Modern aircraft are equipped with an automatic tilt function which sets the antenna tilt based on aircraft position altitude and range in weather mode the tilt is set to be above any terrain ahead based on the worldwide navigation database which supplies elevation data to the awr management computer exemple 437 Based on the altitude of the aircraft.Based on the altitude of the aircraft.

To improve the detection of precipitation area s in e g thunderstorms in which ?

Question 193-38 : Lower when the aircraft climbs to a higher altitude higher when the aircraft climbs to a higher altitude lower when the selected range increases higher when the selected range decreases

If we know of the presence of thunderstorms then tilting the radar can be very useful to gather information about the strength of the thunderstorm and the levels at which it is worst .if we are at a level just below the top of the thunderstorm it is likely that we have the tilt set to 0 or even 1 or 2 degrees in order to see the more violent lower section of the thunderstorm if we climb higher perhaps to overfly the storm then that same tilt setting will be looking higher up within the storm and will be seeing the ice crystals rather than the wet hail and large water droplets this is why we would set the tilt further downwards after making such a climb .it is important to remember that there are other questions asking about the tilt setting during take off and climb out well of course the setting at that time of flight would be quite high to see the weather the aircraft is climbing towards and avoid clutter from ground returns after that though the tilt setting should gradually be reduced until the cruise and then in the descent gradually increased again to avoid ground returns .remember also that the radar is automatically stabilised so it follows the horizon plus/minus any tilt not the aircraft attitude plus/minus tilt

When using airborne weather radar in the mapping mode in polar areas one runs ?

Question 193-39 : Mistaking the edge of coastal ice off shore for the real coastline aurora borealis polar light causing false returns getting a distorted picture because of ice reflection underestimating distances because the cold seawater is causing super refraction

Mapping mode is very useful to provide basic orientation relative to significant terrain features it may be used to distinguish land from water by detecting coastlines in map mode the receiver sensitivity is decreased to accomodate terrain characteristics instead of weather this mode enables identification of terrain features such as mountains coastlines bodies of water etc however it is important to note that off shore ice blocks may be mistaken for the real coastline with black areas in between being mistaken for the shadowed lee side of mountains

In order to provide an air traffic services ats surveillance service what ?

Question 193-40 : Any map information needed to provide the surveillance service and when available the aircraft identification and level any map information needed to provide the surveillance service aircraft speed and when available the aircraft identification and level level speed vertical speed an overlay of the terrain and when available the aircraft identification and destination an overlay of the terrain and the aircraft identification speed vertical speed and level

To provide air traffic services ats surveillance service the minimum required information is .. position and. map information which serves as a reference to airspace structure .. if the aircraft is equipped with a transponder depending on the mode of operation additional information may be provided .. mode a provides solely 2d position information that is presented on the screen of the controller in the horizontal plane . mode c provides 3d position information that is presented on the screen of the controller in the horizontal plane with an altitude indication . mode s in addition to the functions of mode c it provides data transmission as well which contains further aircraft derived data exemple 449 Any map information needed to provide the surveillance service, and (when available) the aircraft identification and level.Any map information needed to provide the surveillance service, and (when available) the aircraft identification and level.

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