Vayudoot Aviation

1. An aircraft on a heading of 235°(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.

zero, since quadrantal error affects only the VOR.

a very small value.

zero, since quadrantal error affects only the RBI.

2. The range promulgated in the Air Pilot and flight guides for all NDBs in the UK is the range

Within which bearings obtained by day should be accurate to within 5°.

Up to which bearings can be obtained on 95% of occasions.

Within which a protection ratio of 3:1 is guaranteed by day and night

Within which protection from skywave protection is guaranteed.

3. In an ADF system, night effect is most pronounced

when the aircraft is at low altitude.

when the aircraft is at high altitude.

during long winter nights.

at dusk and dawn.

4. ADF Quadrantal Error is caused by

station interference and/or night effect.

the aircraft's major electrical axis, the fuselage, reflecting and re-radiating the incoming NDB transmissions.

NDB signals speeding up and bending as they cross from a land to water propagation path

static build up on the airframe and St. Elmo's Fire.

5. 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

The increased skip distance that occurs at night.

The possibility of sporadic E returns occurring at night.

Skywave signals from the NDB to which you are tuned.

Long range skywave interference from other transmitters.

6. The protection ratio afforded to NDBs in the UK within the Promulgated range(DOC) applies

by night only.

by day only.

both day and night.

at dawn and dusk.

7. 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.

selecting beacons situated well inland

choosing NON A2A beacons.

only using beacons within the designated operational coverage.

8. Each NDB has a range promulgated in the COMM section of the Air Pilot. Within this range interference from other NDBs should not cause bearing errors in excess of

night ± 5

night ± 10

day ± 6

day ± 5

9. The BFO facility on ADF equipment should be used as follows when an NDB having NON A1A type emission is to be used

BFO on for tuning and identification but may be turned off for monitoring.

BFO on for tuning but can be turned off for monitoring and identification purpose.

BFO off during tuning, identification and monitoring because this type of emission is not modulated.

BFO should be switched on for tuning, ident and monitoring.

10. The principal propagation path employed in an NDB/ADF system is

direct wave

surface wave

ducted wave

skywave

11. The phenomenon of coastal refraction which affects the accuracy of ADF bearings

is most marked at night.

is most marked one hour before to one hour after sunrise and sunset.

can be minimised by using beacons situated well inland.

can be minimised by taking bearings where the signal crosses the coastline at right angles.

12.
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?

D

B

A

C

13. In order to Tune, Identify and Monitor NON A1A NDB emissions the BFO should be used as follows

Tune on Identify off Monitor off

Tune on Identify on Monitor On

Tune on Identify on Monitor off

14. 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'.

Port of track and nearer ‘ A'.

Starboard of track and nearer ‘ A'

Port of track and nearer ‘B'.

15. 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°(T)

225°(T)

279°(T)

145°(T)

16.
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 140° 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?

C

D

B

A

17. 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

inaccurate due to the transmitted wave front decelerating.

further from the coast.

closer to the coast.

co-incident

18. 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 towards

accelerating away from

decelerating away from

decelerating towards

19. When the induced signals from the loop and the sense antenna are combined in an ADF receiver, the resultant polar diagram is

figure of eight shaped

a limacon

a cardioid

circular

20. 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, radial.

at the aircraft, cardioid, bearing.

at the aircraft, limacon, bearing.

at the transmitter, limacon, bearing.

21. The overall accuracy of ADF bearings by day within the Promulgated Range (DOC) is

± 6°

± 3°

± 5°

± 10°

Question Bank

Questions for ADF