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Question 204-1 : In order to indicate unlawful interference with the planned operation of the flight, the aircraft secondary surveillance radar ssr transponder should be selected to ? [ Exam pilot ]
7500.
.7600 radio communication failure...7500 unlawful interference with the planned operation of the flight...7700 emergency situation.
Question 204-2 : An apparent increase in the transmitted frequency which is proportional to the transmitter velocity will occur when ?
The transmitter moves towards the receiver.
.because the radio signals travel at a constant speed assuming they are not refracted by the atmosphere , the receiver can calculate exactly how far away it is from the transmitter..speed is most often calculated by the receiver using the doppler effect, which is the process by which the frequency of a signal changes due to the relative motion of the transmitter. frequency is raised when the transmitter moves towards the receiver.
Question 204-3 : A primary radar operates on the principle of ?
Pulse technique.
Question 204-4 : The main factor that limits the range of an ndb is the ?
Transmitted power.
Question 204-5 : The two main design functions of secondary surveillance radar ssr mode s are ?
Air to ground and ground to air data link communications and improved atc aircraft surveillance capability.
Question 204-6 : A frequency of 10 ghz is considered to be the optimum for use in an airborne weather radar system because ?
The larger water droplets will give good echoes.
.a high frequency is used since it gives strong return of echoes from big water droplets and clouds of high water contents, usually thunderstorm movements, but do not reflect the clouds with lower contents of water or fog.
Question 204-7 : Which of the following is a complete list of airborne weather radar antenna stabilisation axes ?
Roll and pitch.
.weather radar antenna in the nose radome of a boeing 757. 2547.you can clearly see the stabilisation system. 2548
Question 204-8 : In an airborne weather radar that has a colour cathode ray tube crt increasing severity of rain and turbulence is generally shown by a change of colour from ?
Green to yellow to red.
. 2614
Question 204-9 : When an aircraft is operating its secondary surveillance radar in mode c an air traffic controller's presentation gives information regarding the aircraft's indicated flight level in increments of ?
100 ft.
.air traffic controller's presentation gives information regarding the aircraft's indicated flight level mode c in increments of 100 ft. 2615.afr1670 air france 1670.038 3800 ft climbing, m15 control sector m15
Question 204-10 : A radar facility transmitting at a pulse recurrence frequency prf of 1200 pulses/second will have a maximum unambiguous range of approximately ?
69 nm.
.maximum range = pulse repetition time/ 2 x 0,162 nm/microsecond..pulse repetition time = 1 x 106 / recurrence frequency..pulse repetition time = 833.33..maximum range = 833.33/2 x 0,162 = 67.5nm...also.velocity of light = 300000km/s.range = 300000/prf x 2.range = 300000/1200 x 2.range = 125km ==> 67,5nm.
Question 204-11 : The frequency of an ssr ground transmission is ?
1030 +/ 0.2 mhz.
Question 204-12 : The doppler navigation system is based on ?
Radar principles using frequency shift.
.doppler principle.the relative motion between transmitter and receiver causes a proportional frequency shift fd which is known as doppler shift, doppler effect or doppler frequency...transmitter and receiver are screened from each other but use the same aerial. beams are transmitted with a depression angle of 60 and 70 degrees and the receiver measures the reflected frequency shift caused by aircraft's speed along track, ground speed, speed across track and drift...as the transmitter and receiver get closer, a positive shift occurs in fd and as they move far apart, a negative shift occurs in fd.
Question 204-13 : In which mode of operation does the aircraft weather radar use a cosecant radiation pattern ?
Mapping.
. boeing 737ng navigation displays in map mode. 2613
Question 204-14 : The main factor which determines the minimum range that can be measured by a pulsed radar is pulse ?
Length.
.pulse length defines the minimum theoretical range of a radar.
Question 204-15 : Complete the following statement..aircraft surface movement radar operates on frequencies in the i.......... band employing an antenna that rotates at approximately ii.......... revolutions per minute it is iii......... possible to determine the type of aircraft from the return on the radar screen. ?
I shf ii 60 iii sometimes.
Question 204-16 : The maximum pulse repetition frequency prf that can be used by a primary radar facility in order to detect targets unambiguously at a range of 50 nm is. pps = pulses per second ?
1620 pps.
.range = c / 2f..f pps = c velocity of light / 2 x range..range= 50 nm..f = 162000 nm/s / 2 x 50..f = 1620 pulses per second.
Question 204-17 : Ignoring pulse length and fly back, a radar facility designed to have a maximum unambiguous range of 50 km will have a prf pulses per second of ?
3000.
.maximum range = velocity of light x 1/ prf..50 km = 300000 x 1/prf..prf = 300000 / 50 = 6000..but we have to ignore pulse length and fly back, so 6000/2.
Question 204-18 : Which combination of characteristics gives best screen picture in a primary search radar ?
Short pulse length and narrow beam.
Question 204-19 : The minimum range of a primary radar, using the pulse technique, is determined by the i........ the maximum unambiguous range by the ii......... ?
I pulse length ii pulse recurrence frequency.
Question 204-20 : The maximum range of primary radar depends on ?
Pulse recurrence frequency.
.primary radar provides bearing and distance of targets...primary ground radar is used to detect aircraft that are not equipped with a secondary radar transponder...the maximum theoretical unambiguous range if the prf is given using the formula.range in km = 300000/ prf x 2.. prf pulse repetition frequency..take care pulse length defines the minimum theoretical range of a radar.
Question 204-21 : A frequency of airborne weather radar is ?
9375 mhz.
.the wavelength is approximately 3 cm and frequency of most airborne weather radar awr is approximately 9 ghz.
Question 204-22 : Under easa cs 25 colour code rules for electronic flight instrument systems efis , increasing intensity of precipitation are coloured in the order ?
Green, amber/yellow, red, magenta.
. 2616
Question 204-23 : For any given circumstances, in order to double the effective range of a primary radar the power output must be increased by a factor of ?
16.
.to increase the range of a radio transmission the power is increased by a square factor to double its range the power is increased by a 4 factor x2²...but for a primary radar, signal must return to the ground station in order for the radar to work...power output must be increased by a factor of 2²x 2² = 16.
Question 204-24 : A weather radar, set to the 100 nm scale, shows a squall at 50 nm. by changing the scale to 50 nm, the return on the radar screen should ?
Increase in area and move to the top of the screen.
. 2617.by changing the scale to 50 nm, the squall line increases in area and moves to the top of the screen.
Question 204-25 : The code transmitted by a ssr transponder consists of ?
Pulses.
Question 204-26 : In which frequency band do most airborne weather radars operate ?
Shf.
.vor operating frequencies vhf.localiser vhf.marker beacon vhf..dme operating frequencies uhf.glide slope uhf.gnss/gps uhf.l1 and l2 frequencies used by navstar/gps uhf..ils localiser and glide slope vhf and uhf bands...microwave landing system mls shf.airborne weather radars shf.locator lf/mf
Question 204-27 : The maximum range of an en route radar is approximately ?
200 300 nm.
.an aircraft at flight level 410 41000 ft can be seen by a long range radar located at mean sea level at..1.23*sqrt41000 = 250 nm.. sqrt square root.
Question 204-28 : In airborne weather radar awr , the main factors which determine whether a cloud will be detected are ?
Size of the water drops wavelength/frequency used.
. 2618
Question 204-29 : In order to ascertain whether a cloud return on an aircraft weather radar awr is at or above the height of the aircraft, the tilt control should be set to. assume a beam width of 5° ?
2.5° up.
.an aircraft weather radar awr is typically located in the nosecone of the aircraft, behind a radome that is composed of non reflective material..incorporated in the cockpit equipment is a tilt feature, either automatic or manual, which enables the crew to raise or lower the sweep above and below the longitudinal axis of the aircraft..when assessing the intensity of a thunderstorm, the tilt should be adjusted to the middle and lower portions of the system where the density of precipitation provides the most accurate indications of size and intensity.. 2619
Question 204-30 : In relation to radar systems that use pulse technology, the term pulse recurrence rate prr signifies the ?
Number of pulses per second.
Question 204-31 : What is the maximum number of usable secondary surveillance radar ssr transponder codes in mode a ?
4096.
.squawk codes are four digit octal numbers the dials on a transponder read from 0 to 7, inclusive..thus the lowest possible squawk is 0000 and the highest is 7777. four octal digits can represent up to 4096 different codes.
Question 204-32 : Which of the following equipments uses primary radar principles ?
Airborne weather radar awr.
.radar is a distance measuring system using the principle of radio echoing. the term radar is an acronym for radio detecting and ranging. it is a method for locating targets by using radio waves. the transmitter generates microwave energy in the form of pulses. these pulses are then transferred to the antenna where they are focused into a beam by the antenna. the radar beam is much like the beam of a flashlight. the energy is focused and radiated by the antenna in such a way that it is most intense in the center of the beam with decreasing intensity near the edge. the same antenna is used for both transmitting and receiving. when a pulse intercepts a target, the energy is reflected as an echo, or return signal, back to the antenna. from the antenna, the returned signal is transferred to the receiver and processing circuits located in the receiver transmitter unit. the echoes or returned signals are displayed on an indicator..this is the same principle uses for an airborne weather radar.
Question 204-33 : Which of the following equipments works on the interrogator/transponder principle ?
Secondary surveillance radar ssr.
Question 204-34 : In order to indicate an emergency situation, the aircraft secondary surveillance radar ssr transponder should be set to ?
7700.
.7600 radio communication failure...7500 unlawful interference with the planned operation of the flight...7700 emergency situation.
Question 204-35 : The theoretical maximum range for an airborne weather radar is determined by the ?
Pulse recurrence frequency.
Question 204-36 : The selection of code 7500 on an aircraft ssr transponder indicates ?
Unlawful interference with the planned operation of the flight.
.7500 unlawful interference with the planned operation of the flight...7600 radio communication failure...7700 emergency situation.
Question 204-37 : The selection of code 7700 on an aircraft ssr transponder indicates ?
An emergency.
.7700 emergency situation...7600 radio communication failure...7500 unlawful interference with the planned operation of the flight.
Question 204-38 : In a primary radar using pulse technique, pulse length determines ?
Minimum measurable range.
.pulse length defines the minimum theoretical range of a radar..pulse repetition frequency prf gives the maximum theoretical unambiguous range of the radar..range in km = 300000/ prf x2..if you search for the prf.prf = 300000 / range in km x 2.
Question 204-39 : In a primary radar using pulse technique, pulse recurrence frequency determines ?
Maximum theoretical range.
.pulse length defines the minimum theoretical range of a radar...pulse repetition frequency prf gives the maximum theoretical unambiguous range of the radar.. maximum theoretical range = velocity of light / 2 x pulse repetition frequency.
Question 204-40 : Which of the following radar equipments operate by means of the pulse technique.1. aerodrome surface movement radar.2. airborne weather radar.3. secondary surveillance radar ssr.4. aerodrome surveillance approach radar ?
1, 2, 3 and 4.
.pulse technique.radar involves the transmission of pulses of electromagnetic waves by means of a directional antenna some of the pulses are reflected by objects that intercept them. the reflections are picked up by a receiver, processed electronically, and converted into visible form by means of a cathode ray tube. the range of the object is determined by measuring the time it takes for the radar signal to reach the object and return. the object's location with respect to the radar unit is determined from the direction in which the pulse was received. in most radar units the beam of pulses is continuously rotated at a constant speed, or it is scanned swung back and forth over a sector, also at a constant rate. the velocity of the object is measured by applying the doppler principle if the object is approaching the radar unit, the frequency of the returned signal is greater than the frequency of the transmitted signal if the object is receding from the radar unit, the returned frequency is less and if the object is not moving relative to the radar unit, the return signal will have the same frequency as the transmitted signal...aerodrome surface movement radar, airborne weather radar, secondary surveillance radar ssr and aerodrome surveillance approach radar operate by means of the pulse technique.
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