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#1. Assuming the maximum likely error in VOR to be 5.5°, what is the maximum distance apart that beacons can be situated on the centre line of a UK airway in order that an aircraft can guarantee remaining within the airway boundary?
An airway is 10nm wide and the Vor is on the middle so its 5nm either side of the Vor.
The error is 5.5° so we cn use the Track Error(1 in 60 rule) formula.
TE= Distance off/Distance covered *60
We know the TE=5.5° and Max Dist off can be 5nm so it gives the Dist covered as 54.54( 5/5.5*60)
This means that with an error of 5.5 °u can stay within the airways for sure till 54.5nm with one vor. At that point u need the signal from another vor wch cant be more than 54.5nm away with the same error. So total distance comes to 54.5 54.5=109nm.
#2. The Designated Operational Coverage quoted for VOR beacons in the COMM section of the Air Pilot:
The Designated Operational Coverage (DOC) of a VOR, the range, sector and altitude where freedom from interference is guaranteed, is given in the AIP.
This is valid both by day and by night (unlike NDBs).
Outside the DOC, interference from other stations is possible.
ICAO require bearing accuracy of ± 5° on 95% of occasions.
Because of its higher frequency and line of sight transmission VOR is free from sky wave interference and coastal refraction.
Any bending of the signal by the structure of the aeroplane would not affect the indicated bearing so quadrantal error does not exist with VORs
#3. What is the theoretical maximum range that an aircraft at flight level 360 will obtain from a VOR beacon situated at 900 feet above mean sea level?
Max theoretical range (in nm) = 1.23 x square root of H1 plus 1.23 x square root of H2
H1 = height of the transmitter (in feet above msl)
H2 = height of the receiver (in feet above msl)
#4. A Conventional VOR:
VOR bearing is obtained by phase comparison:
An aircraft’s VOR receiver measures the phase difference (angular difference) between two signals from the VOR transmitter:
a 30Hz frequency modulated omni-directional, reference signal which produces constant phase regardless of a receiver’s bearing from the VOR, and
a 30Hz amplitude modulated variable phase (directional) signal created by the rotating transmission pattern (limaçon).
#5. An aircraft is tracking away from a VOR on the 050 radial with 10° starboard drift. An NDB lies to the east of the VOR. Which of the RMIs illustrated below shows the aircraft when it is obtaining a relative bearing of 100° from the NDB?
Tracking away from the vor , rmi would look like this,
tail indicates the radial as needle points to the vor
there is a NDB east of vor
now as we are dealing with NDB lets take wind into consideration
at the 050 radial in order to maintain track nose would be in to the wind,
how much?
the same as the drift component 10°
wind is from left (starboard drift)
heading will be to the left to counteract heading will be 040
Relative bearing is 100 ° so add 100 to 040°
RBI needle will point 140°
Result would be
#6. The OBS on a deviation indicator is set to 330° and gives a 3 dots fly right demand with FROM indicated. What is the QDM of the aircraft to the station?
Each dot is equal to 2° displacement
3 dots are 6° displacement
if obs Is selected 330° and aircraft’s shows fly right it means if you fly right you will achieve 330° , hence currently you are on 324°
as 3 dots are 6° displacement
Radial will be 324-180 = 144°
#7. An aircraft is homing towards a VOR which marks the centre line of an airway. The beacon is 100 nms distant. If the pilot had the airway QDM set on the OBS what deflection of the deviation indicator would be given if the aircraft was on the boundary of the airway? Assume that one dot equals 2 degrees.
Airway is 5nm either side of centre line
Now Frm 1 in 60 rule
X = (5*60)/100
x=3 deg
I.e 1.5 dots
#8. What is the theoretical maximum range that an aircraft at flight level 420 will obtain from a VOR beacon situated at 400 feet above mean sea level?
#9. Concerning conventional and Doppler VORs (DVOR), which of the following is correct?
#10. In a Doppler VOR (DVOR) the reference signal is _________, the bearing signal is _________ and the direction of rotation of the bearing signal is _________:
Doppler VORs are second generation VORs. Although their transmission frequencies are the same, the transmitted bearing accuracy is improved as the transmissions are less sensitive to site error.
The transmission differences are:
The reference signal is AM
The variable phase directional signal is FM.
#11. An aircraft is attempting to home to a VOR on the 064 radial. The CDI shows 4 dots fly right with a TO indication. At the same time the co-located DME shows a range of 45 nm. Where is the aircraft in relation to the required track?
#12. A VOR beacon ceases to transmit its normal identification which is substituted by ‘TST’. This means that:
If a VOR is transmitting the identification TST it indicates that the VOR is on test and the bearing information should not be used.
#13. What is the approximate maximum range that an aircraft flying at 25000′ would expect to obtain from a VOR beacon situated 900′ above mean sea level?
#14. An aircraft is on the airway boundary range 100 nm from a VOR marking the airway centre line. Assuming that each dot equates to 2° how many dots deviation will be shown on the deviation indicator?
Airway is 5nm either side of centre line
Now Frm 1 in 60 rule
X = (5*60)/100
x=3 deg
I.e 1.5 dots
#15. An aircraft is required to intercept and home to a VOR along the 064 Radial. The OBS should be set to:
If you intercept a radial to fly FROM a station, then the radial you wish to intercept must be on the TOP of the OBS, and a FROM indication must be showing.
If you wish to intercept a radial TO a station, then the radial ou wish to intercept must be set on the BOTTOM of the obs… i.e set the reciprocal on the top of the obs, and a TO indication must be showing.
FROM TOP, TO BOTTOM
#16. An aircraft is tracking away from a VOR on the 150 radial with 10° starboard drift. An NDB lies to the South of the VOR. Which of the RMIs illustrated below shows the aircraft when it is obtaining a relative bearing of 100° from the NDB?
Tracking away from a vor this is how rmi will show,
tail of needle will always show radial,
Wind doesn’t affect the radial of the aircraft
Now to calculate the relative bearing, we have to take wind into consideration
since ac experiences right drift, it’s heading will be into he wind by 10°
aircraft’s heading would be, 140,
since relative bearing is 100° from NDB add 100° to heading,
it will give you rbi pointing to the NDB at 240
#17. Assuming the maximum likely error in VOR to be 5°, what is the maximum distance apart that beacons can be situated on the centre line of a UK airway in order that an aircraft can guarantee remaining within the airway boundary?
An airway is 10nm wide and the Vor is on the middle so its 5nm either side of the Vor.
The error is 5° so we cn use the Track Error(1 in 60 rule) formula.
TE= Distance off/Distance covered *60
We know the TE=5° and Max Dist off can be 5nm so it gives the Dist covered as 60 nms
This means that with an error of 5°u can stay within the airways for sure till 60 nm
with one vor. At that point u need the signal from another vor wch cant be more than 60nm away with the same error. So total distance comes to 60×2=120 nm
#18. AN aircraft, heading 150°, is 100 nm north of a VOR, the pilot intends to home to the VOR on the 030 radial. The pilot should set ….. on the OBS and on reaching the 030 radial should turn ….. onto a heading of ….., assuming zero wind.
after the obs is set to 210 it will go in heading 210 and intercept radial
030° and look like this
#19. The type of emission radiated by a VOR beacon is:
The emission characteristics are A9W:
A = main carrier amplitude modulated double side-band.
9 = composite system.( can be single or double channel in this case single Channel )
W = combination of telemetry, (telephony) and telegraphy.
#20. An aircraft wishes to track towards a VOR along the 274 radial. If variation is 10° W what should be set on the OBS?
Vor is magnetic and so is the radial,
it has nothing to do with variation
if you are on radial 274, tail of the needle will be on 274 and head of needle (094°)
will point to the vor,
set the heading on the needle head , 094
#21. An aircraft is tracking away from a VOR on a heading of 287°M with 14° starboard drift. If the variation is 6°W what is the phase difference between the reference and variable phase components of the VOR transmission?
heading of 287°M with 14° starboard drift = 301°
aircraft is tracking away I.e the tail of the needle is heading
tail of the needle is at 301° which is the radial
phase difference between the reference and variable phase components = radial
#22. What is the theoretical maximum range that a pilot would obtain from a VOR situated 900 feet above mean sea level in an aircraft flying at 18,000 feet?
#23. An aircraft is attempting to home to a VOR beacon. The pilot has set 329 on the OBS of the deviation indicator. If the aircraft is situated on the 152 radial then the deviation indicator will show:
Current Radial is 152
radial on a rmi is the tail of the needle
hence head of the needle is pointing 332
Which is also the correct heading as the ac is homing to vor on this heading
from radial 152 to radial 149 will have to turn right to intercept 149
1 dot =2°
3°= 1.5 dot
#24. A VOR receiver in an aircraft measures the phase difference from a DVOR as 220°. Which radial is the aircraft on?
A Radial (QDR) is a magnetic bearing FROM a VOR beacon.
A phase difference measured at the aircraft is corresponding to the Radial.
#25. The RMI indicates the aircraft magnetic heading. To convert the RMI bearings of NDBs and VORs to true bearings, the correct combination for the application of magnetic variation is:
NDB station broadcasts no bearing information. So the aircraft ADF actually determines the QDM by sensing the transmitter bearing relative to its local magnetic north.
If a QDR is needed in this context it will not be computed using the actual variation at the NDB location, it will be the reciprocal angle QDR = QDM 180°.
If the variation changes on the route to the NDB, the ADF will show an updated QDM, and the heading will be adjusted. At the end the route will reach the NDB, though the heading will have changed on the route.
The VOR signals carry the QDR information. The VOR indicator displays this information. The broadcast angle is based on the VOR own magnetic north.
The QDM which the VOR indicates is just the reciprocal of the QDR. Therefore if the variation at the aircraft location is different, this QDM is wrong. This is the reason why it’s clearer with VOR navigation to talk about radial to/from rather than QDM/QDR.
#26. Both the VOR and the ADF in an aircraft are correctly tuned and identified. The indications from both are shown on the RMI illustrated. Use the information to answer the following: The information given on the RMI indicates:
this is hdg
2. The needle points to the vor and the tail is radial
3.
#27. The VOR in an aircraft is correctly tuned and set to define the centre line of an airway within UK airspace which you intend to fly. The indication received on the VOR/ILS deviation indicator is shown below. At the same time the DME gave a range of 90nm from the facility. At the time of the observation, the aircraft’s radial and distance from the airway centre-line were:
OBS 248 with TO indication means selected radial is 068. Each dot and the bulls eye (center circle) equates to a 3 degree deviation. That means we are right of radial 068 by 6 degrees. So the aircraft is on radial 063
*each dot equates 2°
#28. The normal maximum error which might be expected with a VOR bearing obtained within the DOC is:
Site error is caused by uneven terrain such as hills and man-made structures, trees and even long grass, in the vicinity of the transmitter. The error to radiated bearings is termed ‘VOR course-displacement error’. Ground VOR beacon site error is monitored to ± 1°
Propagation error is caused by the fact that, having left the VOR site with ±1° accuracy
Airborne equipment errors are caused by aircraft equipment assessing and converting the phase differences to 1° of bearing ; maximum aircraft equipment error should be 3°.
The above errors are aggregate errors to give a total error of 5°.
#29. An aircraft is tracking away from VOR “A” on the 310° radial with 8° starboard drift; NDB “X” is north of “A”. Which diagram below illustrates the RMI when the aircraft is on its present track with a QDR from “X” of 270°?
The answer demands
1. hdg
2. Radial
3.bearing from ndb
1. hdg
With 8° starboard drift ac in order to counteract drift and follow track will point its nose 8° left making the hdg 302°
2. radial
question says
An aircraft is tracking away from VOR “A” on the 310° radial
the rmi is built to point to the vor and tail will show the radial, 310°
3.
QDR – Mag FROM station
as question says
Which diagram below illustrates the RMI when the aircraft is on its present track with a QDR from “X” of 270°?
again the rmi needle will point to the NDB
#30. The VOR indications on an RMI whose deviation is not zero:
Vor transmits radials which are magnetic ,It produces 360 radials/tracks at 1° spacing which are aligned in relation to magnetic north at the VOR location.
This displacement (or deviation) is presented by a Left / Right needle
all other options do not provide deviation
compass does not provide deviation
relative is used in NDB
#31. An aircraft bears 175°(M) from a VOR. If the aircraft OBS is set to 002 and its heading is 359°(M) which diagram below represents the aircraft VOR/ILS deviation indicator? (assume 1 dot = 2°)
If you intercept a radial to fly FROM a station, then the radial you wish to intercept must be on the TOP of the OBS, and a FROM indication must be showing.
If you wish to intercept a radial TO a station, then the radial ou wish to intercept must be set on the BOTTOM of the obs… i.e set the reciprocal on the top of the obs, and a TO indication must be showing.
FROM TOP, TO BOTTOM.
using above thumb rule radial to intercept will be 182° If obs set on 002°
current radial is 175°( as mentioned 175° magnetic from the vor)
hence 7° Left turn will be required
1 dot is 2°
So 3.5 dots to the left will be required ( centre circle will also be considered a dot )
