Q1. X An aircraft has an RMI with two needles. Assume that: i) The aircraft is outbound from NDB Y on a track of 126° (M) drift is 14° Port. ii) A position report is required when crossing a QDR of 022 from NDB Z. Which of the diagrams below represents the RMI at the time of crossing the reporting point?
A
Q2. #An NDB transmits a signal pattern in the horizontal plane which is:
Omnidirectional
Q3. What is the wavelength of an NDB transmitting on 365 kHz?
822 m
Q4. %**An aircraft is tracking 060° (T) in still air. The relative bearing of an NDB is 035° at 1300. 12 min later the relative bearing is 070° . If the GS is 180 kts, what is the aircraft’s distance from the NDB at 1312:
36 NM
Q5. #Which statement with respect to the range of an NDB?
With propagation over sea the range will be greater than the range with propagation over land
Q6. An aeroplane is tracking towards an NDB maintaining track 120 degrees with 15 degrees starboard (right) drift. The relative bearing indicator (RBI) should indicate a bearing of?
015 degrees relative
Q7. ##*The reading of the RMI bearing is 300 degrees At the tip of the needle. The magnetic variation at the DR position is 24W, the magnetic variation at the NDB is 22W and the deviation is -2 degrees. The compass heading is 020 degrees. The true bearing is?
274 degrees
Q8. ***When flying over the sea and using an inland NDB to fix position with a series of position lines, the plotted position in relation to the aircraft’s actual position will be:
closer to the coast
Q9. *There are two NDBs, one 80 NM inland, and the other 50 NM inland from the coast. Assuming that the error caused by coastal refraction is the same for both propagations, the extent of the error in a position line plotted by an aircraft that is over water will be?
Greater from the beacon that is 80 NM inland
Q10. The magnitude of the error in position lines derived from ADF bearings that are affected by coastal refraction may be reduced by:
choosing beacons on or near the coast
Q11. A radio beacon has an operational range of 10 NM. By what factor should the transmitter power be increased in order to achieve an operational range of 30 NM?
Nine
Q12. # With regard to the range of NDBs and the accuracy of the bearings they provide it can be stated that in general at night?
The range increases and the accuracy decreases
Q13. When the induced signals from the loop and the sense antenna are combined in an ADF receiver, the resultant polar diagram is:
a cardioid
Q14. %*An airplane is tracking away from an NDB maintaining track 120 degrees with 15 degrees starboard (right) drift. The relative bearing indicator (RBI) should indicate a bearing of?
195 degrees relative
Q15. %*The ADF of an aircraft on a heading of 189° (T) will experience the greatest effect due to quadrantal error if the NDB bears:
$234^{circ}(T)$
Q16. An aircraft on a heading of 225° (M) shows an RMI reading of 090° with respect to an NDB. Any quadrantal error which is affecting the accuracy of this bearing is likely to be:
a maximum value
minimum at RB of 360,090,180,270,000.
Only NDB suffers from Quadrantal Error.
VDF and VOR does not suffers form Quadrantal Error
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Quadrantal error in Automatic Direction Finder (ADF) systems arises from the aircraft’s metallic structure reflecting and re-radiating incoming signals, leading to bearing inaccuracies. This error is most pronounced when the signal arrives from angles of 45°, 135°, 225°, or 315° relative to the aircraft’s nose.
In this scenario, the aircraft’s magnetic heading is 225°, and the Radio Magnetic Indicator (RMI) shows a bearing to the Non-Directional Beacon (NDB) of 090°. This indicates that the NDB is located at a relative bearing of 135° to the aircraft’s nose (since 225° + 225° = 450°, or 90° ). Given that 225° is one of the angles where quadrantal error reaches its maximum, the bearing accuracy is likely to be significantly affected.
Therefore, in this situation, any quadrantal error affecting the accuracy of the bearing is likely to be at its maximum value.
Q17. # Which of the following is likely to have the greatest effect on ADF accuracy?
Interference from other NDBs, particularly at night
Q18. %* A VOR and an NDB are co-located. You cross the VOR radial of 240 on a heading of 360 (M). In the vicinity of the station, you should read an ADF bearing of..
60
Q19. An aircraft is intending to track from NDB ‘A’ to NDB ‘B’ on a track of 050° (T), heading 060° (T). If the RBI shows the relative bearing of ‘A’ to be 180° and the relative bearing of ‘B’ to be 330° then the aircraft is:
starboard of track and nearer ‘B’
Q20. %*An aeroplane is tracking away from an NDB maintaining track 120 degrees with 12 degrees port drift. The relative bearing indicator (RBI) should indicate a bearing of?
168 degrees relative
Q21. #/The BFO facility on ADF equipment should be used as follows when an NDB having NONA1A type emission is to be used:
BFO should be switched on for tuning, ident and monitoring
Q22. #Errors caused by the effect of coastal refraction on bearings at lower altitudes are maximum when the NDB is:
Inland and the bearing crosses the coast at an acute angle
Q23. #The range promulgated in the AIP and flight guides for all NDBs in the UK is the range:
within which bearings obtained by day should be accurate to within $5 dEGREES
This ensures that within the specified range, bearing errors are limited to ±5 degrees or less during daylight hours only ( not in the night ).
Beyond this published range, bearing errors may increase, and adverse propagation conditions, particularly at night, can further degrade accuracy.
Therefore, the correct interpretation is that the promulgated range for UK NDBs defines the distance within which bearings obtained by day should be accurate to within ±5 degrees.
Q24. # The BFO selector on an ADF receiver is used to:
Hear the IDENT of some NDB stations radiating a continuous wave signal
Q25. A radio beacon has an operational range of 10 NM. By what factor should the transmitter power be increased in order to achieve an operational range of 20 NM?
Four
Q26. **What causes the so-called “night effect”?
A change in the direction of the plane of the polarization due to reflection in the ionosphere
Q27. %*On the QDR of 075 degrees, (in the vicinity of the station) with the magnetic heading of 295 degrees, the relative bearing on the ADF indicator is.
320 degrees
Q28. ADF quadrantal error is caused by:
the aircraft’s major electrical axis, the fuselage, reflecting and re-radiating the incoming NDB transmissions
Q29. *Which statement is correct for tracking towards and NDB in an area with constant wind and constant magnetic variation?
The relative bearing of the NDB should be equal (in magnitude and sign) to the experienced drift angle
Q30. #Factors liable to affect most NDB/ADF system performance and reliability include:
Static interference – night effect – absence of failure warning system
Q31. Each NDB has a range promulgated in the COMM section of the AIP. Within this range interference from other NDBs should not cause bearing errors in excess of:
day $pm 5^{circ}$
Q32. An aircraft is tracking away from an NDB on a track of 023° (T). If the drift is 8° port and variation 10° west, which of the RMIs illustrated below shows the correct indications? (Visual Q.)
D
Q33. % *Given: W/V (T)=230/20 kts. Variation =6E. TAS=80 kts. What should relative bearing from an NDB be maintained in order to achieve an outbound course of 257(M) from overhead the beacon?
188 degrees
Q34. The phenomenon of coastal refraction which affects the accuracy of ADF bearings:
can be minimized by taking bearings where the signal crosses the coastline at right angles
This bending occurs because radio waves travel at different speeds over land and water due to their differing conductivities. Water, being more conductive than land, causes the radio waves to bend toward the coastline as they transition from land to sea or vice versa.
The degree of this bending depends on the angle at which the radio signal intersects the coastline. When the signal crosses the coastline at a acute angle, the bending effect is more pronounced, leading to greater inaccuracies in ADF bearings. Conversely, if the signal crosses the coastline at a right angle (perpendicularly), the change in conductivity affects the wavefront uniformly, minimizing the bending effect.
Therefore, taking bearings where the signal crosses the coastline at right angles reduces the coastal refraction, enhancing the accuracy of ADF readings.
Regarding the timing of coastal refraction effects, while some radio wave propagation phenomena are influenced by time of day—such as “night effect,” which affects ADF accuracy during dawn and dusk—coastal refraction is primarily a function of the physical properties of the terrain and is not significantly affected by the time of day.
Therefore, the statement that coastal refraction is most marked one hour before to one hour after sunrise and sunset is incorrect.
In summary, to minimize errors caused by coastal refraction in ADF bearings, it’s advisable to take bearings where the signal crosses the coastline at right angles. This approach reduces the bending effect of the radio waves, leading to more accurate navigation readings.
Q35. ***If a failed RMI rose is stuck on 090 and the ADF pointer indicates 225, the relative bearing of the station will be?
135 degrees
IF RMI ROSE is stuck , it will act as a RBI.
( to check Relative bearing you can see the difference between RMI heading and tip of the needle in Clockwise.)
Q36. The ADF indication in the cockpit is a?
Relative bearing on a fixed card
Q37. *Quadrantal errors associated with aircraft Automatic Direction Finding (ADF) equipment are caused by:
Signal bending by the aircraft metallic surfaces
Q38. *Which of the following is likely to have the greatest effect on ADF accuracy?
Interference from other NDBs, particularly at night
Q39. If an NDB with a transmitter power of 25 kW which has a range of 50 NM is adjusted to give a power output of 100 kW the new range of the NDB will be approximate:
100 NM
Q40. **A VOR and an NDB are co-located. An aircraft equipped with an RMI is flying away from the beacons on a radial of 090 degrees through an area where magnetic variation is changing rapidly. Which statement is correct?
The ADF needle moves, the VOR needle does not
Q41. % You are on a magnetic heading of 055 degrees, and your ADF indicates a relative bearing of 325 degrees. The QDM is?
020 degrees
Q42. *What actually happens in the ADF receiver when the BFO position is selected?
The BFO circuit imposes a tone onto the carrier wave to make the NDB’s ident audible
Q43. **** In order to Tune, Identify and Monitor NONA1A NDB emissions the BFO should be used as follows:
Tune On; Identify On; Monitor On
Q44. The overall accuracy of ADF bearings by day within the promulgated range (DOC) is:
$pm5^{circ}$
Q45. #In order to obtain an ADF bearing the:
Signal must be received by both the sense and loop aerials
in question they are talking about getting bearing information which is monitoring stage.
also it is not mentioned – A2A or A1A.
In A2A for monitoring BFO not required.
“”” so BFO must be on “” this answer is wrong
Q46. ### The reading of the tip of the RMI needle is 100 degrees. The magnetic variation at the DR position is 20W, the magnetic variation at the NDB is 10E and deviation is 5W degrees. The compass heading is 020 degrees. The true bearing is?
075 degrees
Q47. *The phenomena of coastal refraction affecting ADF bearings is caused by the signal……. when it reaches the coastline and bending……. the normal to the coast:
accelerating; away from
Q48. Which of the following is the ICAO allocated frequency band for ADF receivers?
200-1750 kHz
Q49. *On which of the following displays are you able to get a direct read-out (no calculation is necessary from the pilot) of the magnetic bearing from the aircraft to the NDB?
Moving card ADF and RMI
Q50. * Which statement about the errors and effects on NDB radio signals is correct?
The mountain effect is caused by reflections onto steep slopes of mountainous terrain which may cause big errors in the bearing
Q51. *~*An aircraft is intending to track from NDB ‘A’ to NDB ‘B’ on a track of 090° (T), heading 100° (T). If the RBI shows the relative bearing of ‘A’ to be 180° and the relative bearing of ‘B’ to be 345° then the aircraft is:
starboard of track and nearer ‘A’
Q52. An aeroplane is tracking away from an NDB maintaining track 020 degrees with 5 degrees starboard (right) drift. The relative bearing indicator (RBI) should indicate a bearing of?
185 degrees relative
Outbound Track: 020°
Drift: 5° starboard (right)
Magnetic Heading (MH): 020° – 5° = 015°
Magnetic Bearing to Station (MB): 020° + 180° = 200°
Relative Bearing (RB) = Magnetic Bearing to Station (MB) – Magnetic Heading (MH)
Relative Bearing (RB): 200° – 015° = 185°
Therefore, the RBI should indicate a relative bearing of 185°.
Q53. %* An NDB is on a relative bearing of 316 degrees from an aircraft. Given: Compass heading 270. Deviation =2W. Variation at the aircraft =30E. Variation at the station =28E. Calculate the true bearing of the NDB from the aircraft?
254 degrees
Q54. *In an ADF system, night effect is most pronounced:
at dusk and dawn
Q55. # In order to resolve the 180° directional ambiguity of a directional LOOP aerial its polar diagram, is combined with that of a SENSE aerial………to produce a………whose single null ensures the ADF needle moves the shortest distance to indicate the correct…………
at the aircraft, cardioid, bearing
Q56. The protection ratio afforded to NDBs in the UK within the promulgated range (DOC) applies:
by day only
but for VOR = = +/- 5 degree ; vailed for day and night both
Q57. *** The protection ratio of 3:1 that is provided within the promulgated range/designated operational coverage of an NDB by day cannot be guaranteed at night because of:
long range sky wave interference from other NDB transmitters
Q58. An NDB is on a relative bearing of 316 degrees from the aircraft. Given: Compass heading 265 degrees. At aircraft deviation =3W Variation =36E. At station variation =34E. Calculate the true bearing of the NDB from the aircraft?
254 degrees
Q59. ***Which statement with respect to the range of an NDB in an area with NO wind and constant magnetic variation?
The relative bearing of the NDB should be kept $000/180$ degrees
Q60. #The quadrantal error of an ADF?
Is caused by the refraction from the aircraft’s fuselage and is compensated for
Q61. **Which one of the following disturbances is most likely to cause the greatest inaccuracy in ADF bearings?
Local thunderstorm activity
Q62. #Night effect in an ADF may cause?
Fluctuating indications of the needle on the RMI
Q63. *The principal propagation path employed in an NDB/ADF system is:
surface wave
Q64. An RMI shows the bearing of an NDB as 020° The heading of the airplane is 020°(M). In order to intercept an outbound course of 330° (from the NDB) at an angle of 40°, the airplanes heading should be altered to:
10
Q65. A RMI shows the bearing of an NDB as 040°. The heading of the aeroplane is 020° (M). In order to intercept an outbound course of 360° (from the NDB) at an angle of 15°, the aeroplane heading should be altered to:
15