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► A VOR is sited at position A (45° 00 minutes N, 010° 00 minutes E). An aircraft is located at position B (44° 00 minutes N, 010° 00 minutes E). Assuming that the magnetic variation at A is 10°W and at B is 15°W, the aircraft is on VOR radial:
A) 190°
B) 195°
C) 185°
D) 180°
The VOR is to the NORTH of the aircraft so from VOR to ACFT is 180° (T). For VOR, we take the variation at the station so 180°(T) + 10W = 190°(M)
► An aircraft is flying on the true track 090° towards a VOR station located near the equator where the magnetic variation is 15°E. The variation at the aircraft position is 8°E. The aircraft is on VOR radial:
A) 255°
B) 278°
C) 262°
D) 285°
These type of Question just test your knowledge about which variation to apply. (VOR takes the variation at the station, for a NDB we would take the variation at the aircraft).
Form VOR to ACFT = 270°
270°(T) - 15E = 255°(M)
► An aircraft is 100 NM from a VOR facility. Assuming no error when using a deviation indicator where 1 dot = 2° deviation. How many dots deviation from the centre line of the instrument will represent the limits of the airway boundary? (Assume that the airway is 10 NM wide)
A) 6.0
B) 3.0
C) 4.5
D) 1.5
TE = ( Distance off track (DOT) / Distance along track (DAT) ) x 60
DOT = 5NM (airway is 10NM wide so from centreline of airway to its boundary is 5)
DAT = 100NM
TE = 5 / 100 x 60
TE = 3°
1 dot represents 2° so 3° is 1.5 dots
► An airway 10 NM wide is to be defined by two VORs each having a resultant bearing accuracy of plus or minus 5.5°. In order to ensure accurate track guidance within the airway limits the maximum distance apart for the transmitter is approximately:
A) 165 NM
B) 50 NM
C) 105 NM
D) 210 NM
TE = ( Distance off track (DOT) / Distance along track (DAT) ) x 60
5.5° = 5NM / DAT x 60
DAT = 54.5 NM
But it is defined by the two VORs so 54.5 + 54.5 = 109 NM (105 being closest)
► The maximum theoretical range at which an aircraft at FL230 may receive signals from a VOR facility sited at mean sea level is:
A) 230 NM
B) 190 NM
C) 170 NM
D) 151 NM
MTR = 1.25 x (SQRT(0) + SQRT(23000))
MTR = 1.25 x SQRT(23000)
MTR = 190
► An aircraft is flying on a heading of 270°(M). The VOR OBS is also set to 270° with the full left deflection and FROM flag displayed. In which sector is the aircraft from the VOR ground station?
A) SE
B) SW
C) NW
D) NE
The OBS is set to 270° and we see a FROM flag meaning we are flying AWAY from the VOR station. This could only place us on a outbound radial 270. Should the Question have said OBS 270° and a TO flag showing than we would be flying towards the station and we'd be positioned on the radial 90° inbound.
We have already established that we are in the West sector of the VOR. Now we need to find out if we are NW or SW. The heading is 270° so our nose is pointing West aswel and the Question states we have a full left deflection meaning that the radial 270 lies to our left (we are right of the radial). This places us in the NW sector.
► An aircraft is on radial 120 with a magnetic heading of 300°, the track selector (OBS) reads: 330. The indications on the Course Deviation Indicator (CDI) are "fly":
A) left with FROM showing
B) right with TO showing
C) right with FROM showing
D) left with TO showing
We are on the radial 120° which means 300° towards the station (reciprocal). The heading is also 300° so we are flying inbound (TO flag).
The OBS is set to 330° which lies to the right of 300° which we are flying at the moment. So we should turn to the left.
Another way to see it is to convert the OBS to a radial aswel = radial 150 (reciprocal) and see where that radial lies in comparison to our current radial (120) = To the left.
► Given: Course Deviation Indicator (CDI) for a VOR is selected to 090°. From/To indicator indicates "TO". CDI needle is deflected halfway to the right. On what radial is the aircraft?
A) 085
B) 275
C) 265
D) 095
If we are flying inbound on 90° Selected on CDI than we must flying on VOR radial 270°.
The deflection is to the right so we are flying left of the radial 270° (only 1 answers corresponds to this position , 275°). Full deflection is 10° so halfway is 5° deviation to the right.
► Given: Aircraft heading 160°(M). Aircraft is on radial 240° from a VOR. Selected course on HSI is 250°. The HSI indications are deviation bar:
A) ahead of the aeroplane symbol with the TO flag showing
B) behind the aeroplane symbol with the TO flag showing
C) ahead of the aeroplane symbol with the FROM flag showing
D) behind the aeroplane symbol with the FROM flag showing
The aircraft is currently on radial 240° from the VOR and nose is pointing towards 160°. We are flying away from the station so FROM flag is shown.
The course selected is 250° which lies BEHIND us.
► OBS 123, TO/FROM showing TO, CDI is indicating 4 dots right on a 5-dot indicator. On what radial is your position?
A) Radial 295
B) Radial 131
C) Radial 311
D) Radial 115
123° Selected = Radial 303° and we are flying inbound (TO flag)
CDI is indicating that we are left of 303° (radial lies to the right of us) so we need to add the deviation.
4 dots on a 5 dot indicator = (10/5 x 4) 8°
303 + 8 = 311°
► The maximum width of the cone of silence above a VOR at 30.000 ft is:
A) 4.1 NM
B) 8.2 NM
C) 11.6 NM
D) 5.8 NM
We can construct a triangle with the known values:
"The ICAO limits of the cone of confusion are up to 50° from the vertical" so Tan(50°)
Opposite side = what we are trying to calculate
Adjacent side = 30.000ft or 4.9 NM
Tan(50) = O / 4.9
O = 1.19 x 4.9
O = 5.8 NM
BUT this is only half the width of the cone (as we can see in the sketch) so 5.8 x 2 = 11.6 NM
A) 190°
B) 195°
C) 185°
D) 180°
The VOR is to the NORTH of the aircraft so from VOR to ACFT is 180° (T). For VOR, we take the variation at the station so 180°(T) + 10W = 190°(M)
► An aircraft is flying on the true track 090° towards a VOR station located near the equator where the magnetic variation is 15°E. The variation at the aircraft position is 8°E. The aircraft is on VOR radial:
A) 255°
B) 278°
C) 262°
D) 285°
These type of Question just test your knowledge about which variation to apply. (VOR takes the variation at the station, for a NDB we would take the variation at the aircraft).
Form VOR to ACFT = 270°
270°(T) - 15E = 255°(M)
► An aircraft is 100 NM from a VOR facility. Assuming no error when using a deviation indicator where 1 dot = 2° deviation. How many dots deviation from the centre line of the instrument will represent the limits of the airway boundary? (Assume that the airway is 10 NM wide)
A) 6.0
B) 3.0
C) 4.5
D) 1.5
TE = ( Distance off track (DOT) / Distance along track (DAT) ) x 60
DOT = 5NM (airway is 10NM wide so from centreline of airway to its boundary is 5)
DAT = 100NM
TE = 5 / 100 x 60
TE = 3°
1 dot represents 2° so 3° is 1.5 dots
► An airway 10 NM wide is to be defined by two VORs each having a resultant bearing accuracy of plus or minus 5.5°. In order to ensure accurate track guidance within the airway limits the maximum distance apart for the transmitter is approximately:
A) 165 NM
B) 50 NM
C) 105 NM
D) 210 NM
TE = ( Distance off track (DOT) / Distance along track (DAT) ) x 60
5.5° = 5NM / DAT x 60
DAT = 54.5 NM
But it is defined by the two VORs so 54.5 + 54.5 = 109 NM (105 being closest)
► The maximum theoretical range at which an aircraft at FL230 may receive signals from a VOR facility sited at mean sea level is:
A) 230 NM
B) 190 NM
C) 170 NM
D) 151 NM
MTR = 1.25 x (SQRT(0) + SQRT(23000))
MTR = 1.25 x SQRT(23000)
MTR = 190
► An aircraft is flying on a heading of 270°(M). The VOR OBS is also set to 270° with the full left deflection and FROM flag displayed. In which sector is the aircraft from the VOR ground station?
A) SE
B) SW
C) NW
D) NE
The OBS is set to 270° and we see a FROM flag meaning we are flying AWAY from the VOR station. This could only place us on a outbound radial 270. Should the Question have said OBS 270° and a TO flag showing than we would be flying towards the station and we'd be positioned on the radial 90° inbound.
We have already established that we are in the West sector of the VOR. Now we need to find out if we are NW or SW. The heading is 270° so our nose is pointing West aswel and the Question states we have a full left deflection meaning that the radial 270 lies to our left (we are right of the radial). This places us in the NW sector.
► An aircraft is on radial 120 with a magnetic heading of 300°, the track selector (OBS) reads: 330. The indications on the Course Deviation Indicator (CDI) are "fly":
A) left with FROM showing
B) right with TO showing
C) right with FROM showing
D) left with TO showing
We are on the radial 120° which means 300° towards the station (reciprocal). The heading is also 300° so we are flying inbound (TO flag).
The OBS is set to 330° which lies to the right of 300° which we are flying at the moment. So we should turn to the left.
Another way to see it is to convert the OBS to a radial aswel = radial 150 (reciprocal) and see where that radial lies in comparison to our current radial (120) = To the left.
► Given: Course Deviation Indicator (CDI) for a VOR is selected to 090°. From/To indicator indicates "TO". CDI needle is deflected halfway to the right. On what radial is the aircraft?
A) 085
B) 275
C) 265
D) 095
If we are flying inbound on 90° Selected on CDI than we must flying on VOR radial 270°.
The deflection is to the right so we are flying left of the radial 270° (only 1 answers corresponds to this position , 275°). Full deflection is 10° so halfway is 5° deviation to the right.
► Given: Aircraft heading 160°(M). Aircraft is on radial 240° from a VOR. Selected course on HSI is 250°. The HSI indications are deviation bar:
A) ahead of the aeroplane symbol with the TO flag showing
B) behind the aeroplane symbol with the TO flag showing
C) ahead of the aeroplane symbol with the FROM flag showing
D) behind the aeroplane symbol with the FROM flag showing
The aircraft is currently on radial 240° from the VOR and nose is pointing towards 160°. We are flying away from the station so FROM flag is shown.
The course selected is 250° which lies BEHIND us.
► OBS 123, TO/FROM showing TO, CDI is indicating 4 dots right on a 5-dot indicator. On what radial is your position?
A) Radial 295
B) Radial 131
C) Radial 311
D) Radial 115
123° Selected = Radial 303° and we are flying inbound (TO flag)
CDI is indicating that we are left of 303° (radial lies to the right of us) so we need to add the deviation.
4 dots on a 5 dot indicator = (10/5 x 4) 8°
303 + 8 = 311°
► The maximum width of the cone of silence above a VOR at 30.000 ft is:
A) 4.1 NM
B) 8.2 NM
C) 11.6 NM
D) 5.8 NM
We can construct a triangle with the known values:
"The ICAO limits of the cone of confusion are up to 50° from the vertical" so Tan(50°)
Opposite side = what we are trying to calculate
Adjacent side = 30.000ft or 4.9 NM
Tan(50) = O / 4.9
O = 1.19 x 4.9
O = 5.8 NM
BUT this is only half the width of the cone (as we can see in the sketch) so 5.8 x 2 = 11.6 NM
