仪表等级飞行员理论培训stage1-107 VOR

CDI / TO-FROM indications will always be as if the aircraft were actually heading in the direction you have set in the OBS course selector (regardless of your actual heading)!
VOR VORTAC VOR/DME
108.00-117.95 MHz
VHF frequencies have “line of sight” limitation
VOR stations transmit radio beams, or Radials, which radiate outward FROM the station in every direction, like spokes on a wheel
OFF or NAV FLAG RIGHTNEEDLE
030 FROM Or 210 TO RIGHT NEEDLE
030 FROM Or 210 TO LEFT NEEDLE
210 FROM Or 030 TO RIGHT NEEDLE
210 FROM Or 030 TO LEFT NEEDLE
210 FROM Or 030 TO CENTERED NEEDLE
Station Passage
Close to the station Cone of confusion
CDI needle fluctuates First complete reversal of TO/FROM is station passage
The TO/FROM Indicator
Only one VOR receiver is required for instrument flight But having 2 helps simplify your arrival at intersections
2 centered needles tells you that you’ve arrived at the intersection with 1 receiver, track your course and tune in the off-airway radial with FROM Needle will deflect toward off airway station until you arrive at intersection then it will center and move away from station after you pass the intersection
REMEMBER: The VOR indicates your position relative to selected OBS course as if you were actually making good that course!
REVERSE SENSING
VOR INTERSECTIONS
CONE OF CONFUSION: over the station
ZONE OF AMBIGUITY: “ABEAM” the station The VOR will indicate “OFF” or “NAV” flag indications when over or abeam the station or when out of range and not receiving a reliable signal.
indications depend on aircraft’s POSITION
ONLY, regardless of heading!
Βιβλιοθήκη Baidu
All aircraft located in a POSITION where flying in the direction selected on the OBS would take them toward the station will have a TO indication
Check TO-FROM window “TO”- selected course will take you generally
TO station “FROM”- selected course will take you generally FROM station
Identifying a Station
Airborne Equipment
Course Index
Unreliable Signal Flag
CDI Needle
Omni Bearing Selector Knob TO/FROM Indicator 2o dots
VOR INDICATOR
Each dot is 2 degrees off course •5 dots sensitivity ; 10 degrees full-scale deflection
120 Deg “FROM”
300 Deg “TO”
VOR ORIENTATION DIAGRAM
The course line (depicted by the red arrow) divides the left /right halves of the compass rose. @ 90 degrees from the selected course (depicted by the green line) divides the TO/FROM halves of the compass rose.
The TO/FROM Indicator
The TO/FROM Indicator
CDI / TO-FROM indications depend on aircraft’s POSITION ONLY. VOR indications are independent of aircraft heading!
VOR CLASSES/Standard Service Volumes
VOR classification in A/FD “radio aids to navigation”
AIM 1-1-8
Terminal VOR
Located at Airports for instrument approaches 25 n.m. 1,000AGL- 12,000 AGL
Aircraft is located AWAY from needle Needle represents selected course line
Each dot is 2 degrees off course
5 dot sensitivity: 10 degrees full-scale deflection
Pull “Volume/Ident” knob Listen to Morse Code Identifier Compare it to desired station on chart Wrong code - Wrong station No code - No station “TEST” ( _ . … _ ) code - Station under maintenance VOR code: approx. every 10 seconds DME code: approx. every 30 seconds
Reverse Sensing
VOR system doesn’t know aircraft’s heading
It senses your position relative to selected course CDI compares your position to OBS course If reciprocal of course selected Reverse sensing occurs (everything is backward) To avoid reverse sensing, set OBS to desired course AND fly a heading that closely matches your selected course
VOR – BASIC OPERATION
VOR GROUND STATION
REFERENCE SIGNAL
VARIABLE SIGNAL
VOR – BASIC OPERATION
IN PHASE: REFERENCE-VARIABLE SIGNAL (360) OUT OF PHASE: VARIABLE SIGNAL (090) OUT OF PHASE: VARIABLE SIGNAL (180) OUT OF PHASE: VARIABLE SIGNAL (360-000)
VOR orientation
TO
WHERE ARE YOU?
VOR orientation
TO
Is this where you thought?
VOR Orientation
FRO M
WHERE?
VOR Orientation
FROM
Is this where you thought?
VOR intercept angle
All aircraft located in a POSITION where flying in the direction
selected on the OBS would take them away from the station will
have a FROM indication
CDI / TO-FROM
Low Altitude VOR
40 n.m. 1,000 AGL - 18,000 AGL at altitudes > 18,000 AGL possible interference
High Altitude VOR
40 n.m. 1,000AGL- 14,500 AGL 100 n.m. 14,500 AGL - 18,000 AGL 130 n.m. 18,000 AGL – 45,000AGL 100 n.m FL 450 - FL 600
Radio Navigation:
VOR
Very High Frequency Omni-directional Range
VOR Navigation
Very High Frequency Omnidirectional Range (VOR)
Most common ground based navaid
VOR RADIALS
VOR RADIALS vs. VOR COURSES
Navigation Procedures
Tune: select frequency Identify: listen to Morse code signal Navigate:
Select desired course on OBS Center needle to determine location
Look on the same side as the needle for a heading to intercept Look 30 degrees to the left for a 30 degree intercept
VOR – Intercepting / Tracking Rules of Thumb
Interpreting VOR Indications
Needle centered with “FROM” in window
Aircraft is on radial OBS course Needle centered with “TO” in window Aircraft is on radial reciprocal to OBS course “FROM TOP - TO BOTTOM” Needle NOT centered (L or R of center)