RADIO AIDS OX BACK QUESTIONS - Dgca question bank for pilots

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#1. When would VDF be used for a position fix?

When an aircraft declares an emergency on any frequency.

When joining controlled airspace from uncontrolled airspace.

When declaring an emergency on 121.500 MHz.

When first talking to a FIR on crossing an international boundary.

#2. What equipment does an aircraft need when carrying out a VDF letdown?

VHF radio

None

VOR

VOR/DME

#3. Which of the following is an advantage of a VDF let down?

it is pilot interpreted, so ATC is not required

no special equipment required in the aircraft or on the ground

only a VHF radio is needed in the aircraft

no equipment required in the aircraft

#4. What is the maximum range at which a VDF station at 325 ft can provide a service to an aircraft at FL080?

134nm

107nm

91nm

114nm

#5. Which of the following statements regarding VHF direction finding (VDF) is most accurate?

it is simple requiring only VHF radios on the ground and in the aircraft

it uses line of sight propagation

it is simple and only requires a VHF radio on the ground

It is simple and requires a VHF radio and DF equipment in the aircraft

#6. What is the wavelength corresponding to a frequency of 375 kHz?

800m

8 m

8000m

80m

#7. A NDB transmits a signal pattern which is

a 30 Hz polar diagram

omni-directional

bi-lobal pattern

a beam rotating at 30 Hz

#8. The accuracy of ADF within the DOC by day is:

+/-2°

+/-5°

+/-1°

+/-10°

#9. Given that the compass heading is 270°, the deviation is 2°W, the variation is 30°E and the relative bearing of a beacon is 316°, determine the QDR:

044

224

048

074

#10. Two NDB’s, one 20 nm from the coast and the other 50 nm further inland. Assuming coastal error is the same for each, from which NDB will an aircraft flying over the sea receive the greatest error?

same when the relative bearing is 180/360

the NDB at 50 nm

the NDB at 20 nm

same when the relative bearing is 090/270

#11. Which of the following is likely to have the greatest effect on the accuracy of ADF bearings?

interference between aircraft aerials

frequency drift at the ground station

interference from other NDB's particularly by day

interference from other NDB's, particularly at night

#12. Which of the following are all errors associated with ADF?

night effect, quadrantal error, lane slip

selective availability, coastal refraction, night effect

selective availability, coastal refraction, quadrantal error

mountain effect, station interference, static interference

#13. What action must be taken to receive a bearing from an ADF?

Select the loop position

Select the LOOP position

BFO on

Both the loop and sense aerials must receive the signal

#14. When is coastal error at its worst for an aircraft at low level?

beacon close to the coast at 90° to the coast

beacon inland at an acute angle to the coast

beacon close to the coast at an acute angle to the coast

beacon inland at 90° to the coast

#15. A radio beacon has a range of 10 nm. By what factor should the power be increased to achieve a range of 20 nm?

#16. Which of the following is the most significant error in ADF?

static from Cb

precipitation static

coastal refraction

quadrantal error

#17. Which of the following may cause inaccuracies in ADF bearings?

coastal refraction, slant range, night effect

static interference, height effect, lack of failure warning

lack of failure warning, station interference, static interference

station interference, mountain effect, selective availability

#18. The allocated frequency coverage of NDB’s is:

190 – 1750 kHz

200 – 500 kHz

108 – 117.95 MHz

250 – 450 kHz

#19. The principle used to measure VOR bearings is:

difference in depth of modulation

phase comparison

pulse technique

switched cardioids

#20. When converting VOR and ADF bearings to true, the variation at the …… should be used for VOR and at the …… for ADF.

aircraft, station

station, station

aircraft, aircraft

station, aircraft

#21. An aircraft flies from a VOR at 61N 013W to 58N 013W. The variation at the beacon is 13W and the variation at the aircraft is 5W. What radial is the aircraft on?

005

187

193

#22. In a conventional VOR the reference signal and the variable signal have a 30 Hz modulation. The variable signal modulation is produced by:

a 30 Hz rotation producing a 30 Hz modulation

using Doppler techniques to produce a 30 Hz amplitude modulation

varying the amplitude up and down at +/-30 Hz

adding 30 Hz to the transmitted signal

#23. If the VOR accuracy has a limit of 1.0°, what is the maximum cross track error at 200 nm?

3.5nm

2.5nm

2nm

3nm

#24. What is the maximum distance apart a VOR and TACAN can be located and have the same identification

2000m

600m

60m

#25. What is the maximum distance between VOR beacons designating the centreline of an airway (10 nm wide), if the expected VOR bearing error is 5.5°?

54nm

60nm

120nm

109nm

#26. On a CVOR the phase difference between the AM and FM signals is 30°. The VOR radial is:

330

210

030

150

#27. In a certain VORTAC installation the VOR is coding STN and the DME is coding STZ. This means that the distance between the two beacons is in excess of:

600m

100m

300m

2000m

#28. Using a 5 dot CDI, how many dots would show for an aircraft on the edge of an airway at 100 nm from the VOR beacon?

2.5

1.5

#29. The maximum range an aircraft at FL370 can receive transmissions from a VOR/DME at 800 ft is:

220nm

200nm

275nm

243nm

#30. When tracking a VOR radial inbound the aircraft would fly:

a constant track

a rhumb line track

a great circle track

a constant heading

#31. Which of the following is a valid frequency (MHz) for a VOR?

118.35

112.20

109.90

107.75

#32. Using a VOR beyond the limits of the DOC may result in:

skywave contamination of the VOR signal

scalloping errors

interference from other VOR's operating on the same frequenc

loss of signal due to line of sight limitations

#33. An aircraft is flying a heading of 090° along the equator, homing to a VOR. If variation at the aircraft is 10°E and 15°E at the VOR, what is the inbound radial?

105

075

255

285

#34. When identifying a co-located VOR/DME the following signals are heard in the Morse code every 30 seconds:

4 identifications with the DME at a lower tone

4 identifications with the DME at a higher tone

4 identifications in the same tone

no DME identification, but if the VOR identification is present and a range is indicated then this shows that both are serviceable

#35. What is the maximum range a transmission from a VOR beacon at 169 ft can be received by an aircraft at FL012

60 nm

80 nm

120 nm

220 nm

#36. An aircraft is tracking inbound to a VOR beacon on the 105 radial. The setting the pilot should put on the OBS and the CDI indications are:

105, FROM

105, TO

285, TO

285, FROM

#37. When tracking the 090 radial outbound from a VOR, the track flown is:

a rhumb line

a constant true heading

a straight line

a great circle

#38. The frequency band of VOR is:

VHF

UHF

LF & MF

#39. On which radial from a VOR at 61N025E (VAR 13°E) is an aircraft at 59N025E (VAR 20°E)?

193

167

160

347

#40. What is the minimum height an aircraft must be to receive signals from a VOR at 196 ft amsl at a range of 175 nm?

16000 ft

20000 ft

24000 ft

26000 ft

#41. For a conventional VOR a phase difference of 090° would be achieved by flying …… from the beacon:

West

North

South

East

#42. At a range of 200 nm from a VOR, if there is an error of 1°, how far off the centreline is the aircraft?

1.75 nm

1 nm

3.5 nm

7 nm

#43. The quoted accuracy of VOR is valid:

by day only

at all times except night

at all times

at all times except dawn and dusk

#44. Which of the following provides distance information?

ADF

VOR

VDF

DME

#45. Which of the following would give the best indication of speed?

a VOR on the flight plan route

a DME on the flight plan route

a VOR off the flight plan route

DME off the flight plan route

#46. What happens when a DME in the search mode fails to achieve lock-on?

it stays in the search mode, but reduces to 60 ppps after 15000 pulse pairs

it stays in the search mode at 150 ppps

alternates between search and memory modes every 10 seconds

it stays in the search mode, but reduces to 60 pulse pairs per second (ppps) after 100 seconds

#47. The most accurate measurement of speed by DME for an aircraft at 30000 ft will be when the aircraft is:

overhead the beacon

tracking towards the beacon at 10 nm

passing abeam the beacon at 5 nm

tracking away from the beacon at 100 nm

#48. A DME beacon will become saturated when more than about …… aircraft are interrogating the transponder.

100

200

#49. A typical DME frequency is:

1300 MHz

1000 MHz

1575 MHz

1000 kHz

#50. The DME in an aircraft, cruising at FL210, fails to achieve lock on a DME at msl at a range of 210 nm. The reason for this is:

the aircraft is beyond the maximum usable range for DME

the aircraft signal is too weak at that range to trigger a response

the beacon is saturated

the aircraft is beyond line of sight range

#51. The aircraft DME receiver accepts replies to its own transmissions but rejects replies to other aircraft transmissions because:

the PRF of the interrogations is unique to each aircraft

the pulse pairs from each aircraft have a unique amplitude modulation

the interrogation frequencies are 63 MHz different for each aircraft

the interrogation and reply frequencies are separated by 63 MHz

#52. When an aircraft at FL360 is directly above a DME, at mean sea level, the range displayed will be:

12nm

9nm

6nm

#53. A DME frequency could be:

1000 MHz

10000 MHz

100 MHz

10 MHz

#54. An aircraft at FL360 is 10 nm plan range from a DME. The DME reading in the aircraft will be:

13.6nm

11.7nm

8nm

10nm

#55. A DME transceiver does not lock onto its own reflections because:

the reflections will all fall within the flyback period

it uses MTI

the interrogation and reply frequencies differ

the PRF of the pulse pairs is jittered

#56. What information does military TACAN provide for civil aviation users?

magnetic bearing

DME and magnetic bearing

DME

Nothing

#57. The DME in an aircraft flying at FL430 shows a range of 15 nm from a beacon at an elevation of 167 ft. The plan range is:

16.5 nm

13.5 nm

17.6 nm

15 nm

#58. What are the DME frequencies?

1030 & 1090 MHz

960 &1215 MHz

1030 – 1090 MHz

960 – 1215 MHz

#59. The time from the transmission of the interrogation pulse to the receipt of the reply from the DME ground station is 2000 microseconds (ignore the delay at the DME). The slant range is:

330 nm

185 nm

370 nm

165 nm

#60. The DME counters are rotating continuously. This indicates that:

the DME is trying to lock onto frequency

the DME is receiving no response from the ground station

the DME is unserviceable

the DME is trying to lock onto range

#61. On a DME presentation the counters are continuously rotating. This indicates:

the DME is unserviceable

the DME is receiving no response from the transponder

The transponder is unserviceable

the DME is in the search mode

#62. An aircraft at FL200 is 220 nm from a DME at msl. The aircraft equipment fails to lock on to the DME. This is because:

DME is limited to 200 nm

The aircraft is too low to receive the signal

The aircraft is too high to receive the signal

The beacon is saturated

#63. On an ILS approach you receive more of the 90 Hz modulation than the 150 Hz modulation. The action you should take is:

fly right and down

fly right and up

fly left and down

fly left and up

#64. The errors of an ILS localiser (LLZ) beam are due to:

ground reflections

interference from other systems operating on the same frequency

spurious signals from objects near the runway

emission sidelobes

#65. The amplitude modulation of the ILS outer marker is ……. and it illuminates the …… light in the cockpit.

1300 Hz, blue

400 Hz, blue

400 Hz, amber

1300 Hz, amber

#66. The principle of operation of the ILS localiser transmitter is that it transmits two overlapping lobes on:

the same frequency with different amplitude modulations

the same frequency with different phases

different frequencies with different phases

different frequencies with different amplitude modulations

#67. The ILS glideslope transmitter generates false glidepaths because of:

multiple lobes in the radiation pattern

reflections from obstacles in the vicinity of the transmitter

back scattering of the signals

ground returns from the vicinity of the transmitter

#68. A category III ILS system provides accurate guidance down to:

less than 50 ft

less than 200 ft

less than 100 ft

the surface of the runway

#69. A HSI compass rose is stuck on 200°. When the aircraft is lined up on the centreline of the ILS localiser for runway 25, the localiser needle will be:

centred

centred with the fail flag showing

left of the centre

right of the centre

#70. The coverage of the ILS glideslope with respect to the localiser centreline is:

+/-10° to 25 nm

+/-8° to 10 nm

+/-35° to 17 nm

+/-10° to 8 nm

#71. The middle marker is usually located at a range of ……, with an audio frequency of …… and illuminates the …… light.

4-6 nm, 1300 Hz, white

1 km, 1300 Hz, amber

1 km, 400 Hz, white

1 km, 400 Hz, amber

#72. The sequence of marker colours when flying an ILS approach is:

amber, blue, white

white, blue, amber

blue, white, amber

blue, amber, white

#73. The sensitive area of an ILS is the area aircraft may not enter when:

the ILS is undergoing calibration

category II/III ILS operations are in progress

category 1 ILS operations are in progress

ILS operations are in progress

#74. The ILS localiser is normally positioned:

300 m from the downwind end of the runway

300 m from the upwind end of the runway

300 m from the threshold

200 m abeam the threshold

#75. The audio frequency of the outer marker is:

400 Hz

1300 Hz

3000 Hz

1000 Hz

#76. An aircraft is flying downwind outside the coverage of the ILS. The CDI indications will be:

unreliable in azimuth and elevation

no indications will be shown

reliable in azimuth, unreliable in elevation

reliable in azimuth and elevation

#77. The frequency band of the ILS glidepath is

VLF

UHF

VHF

SHF

#78. In which band does the ILS glidepath operate?

centimetric

decimetric

metric

hectometric

#79. The coverage of MLS is …… either side of the centreline to a distance of

20°, 20 nm

20°, 40 nm

40°, 40 nm

40° 20 nm

#80. Distance on MLS is measured by:

measuring the time taken for the primary radar pulse to travel from the MLS transmitter to the aircraft receiver

phase comparison between the azimuth and elevation beams

co-located DME

measuring the time taken for the secondary radar pulse to travel from the MLS transmitter to the aircraft receiver

#81. Which of the following is an advantage of MLS?

is not affected by heavy precipitation

has a selective access ability

uses the same aircraft equipment as ILS

can be used in inhospitable terrain

#82. The frequency band of MLS is:

VHF

VLF

UHF

SHF

#83. Primary radar operates on the principle of:

pulse technique

transponder interrogation

phase comparison

continuous wave emission

#84. The definition of a radar display will be best with

narrow beamwidth and wide pulsewidth

wide beamwidth and wide pulsewidth

wide beamwidth and narrow pulsewidth

narrow beamwidth and narrow pulsewidth

#85. The main advantage of a continuous wave radar over a pulsed radar is

smaller more compact equipment

more complex equipment but better resolution and accuracy

removes the minimum range restriction

permits measurement of Doppler in addition to improved range and bearing

#86. Which of the following systems use pulse technique? 1. secondary surveillance radar 2. airborne weather radar 3. distance measuring equipment 4. primary radar

2 and 4 only

1 and 3 only

all the above

2 only

#87. To double the range of a primary radar, the power must be increased by a factor of:

A radar signal attenuates with increasing distance from the transmitter. As the signal has to travel out and back the power/range relationship is:

Power available is proportional to the fourth power of range which means that the power
has increased by a factor of 16 to double the range

#88. In a primary pulsed radar the ability to discriminate in azimuth is a factor of:

Rate of rotation

Pulse recurrence rate

Beamwidth

Pulse width

#89. The maximum range of a ground radar is limited by:

peak power

pulse recurrence rate

average power

pulse width

#90. What does pulse recurrence rate refer to?

the number of pulses per second

the ratio of pulse width to pulse repetition period

the number of cycles per second

the delay known as flyback or dead time

#91. The maximum PRF required for a range of 50 nm is:

3280 pps

300 pulses per second (pps)

1620 pps

600 pps

#92. The best radar for measuring very short ranges is:

a pulsed secondary radar

a pulsed primary radar

a continuous wave secondary radar

a continuous wave primary radar

#93. Which is the most suitable radar for measuring short ranges?

millimetric pulse

continuous wave secondary

centimetric pulse

continuous wave primary

#94. The main advantage of a slotted scanner is

sidelobe suppression

removes the need for azimuth slaving

reduces sidelobes and directs more energy into the main beam

can produce simultaneous map and weather information

#95. The maximum unambiguous (theoretical) range for a PRF of 1200 pps is:

134 nm

180 nm

67 nm

360 nm

#96. The PRF of a radar is 450 pps. If the speed of light is 300000 kps, what is the maximum range of the radar?

1326 km

150 km

666 km

333 km

#97. The best picture on a primary radar will be obtained using:

short wavelength, narrow beam

low frequency, narrow beam

high frequency, wide beam

long wavelength, wide beam

#98. Which of the following is a primary radar system?

GPS

AWR

DME

SSR

#99. On what principle does primary ATC radar work?

continuous wave

pulse technique

transponder interrogation

pulse comparison

#100. ATC area surveillance radars will normally operate to a maximum range of:

200 nm

100 nm

400 nm

300 nm