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Flashcards in VHF Omni Directional Range Deck (19)
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0
Q

Standard service volumes

A
  • works on line of site; reception may be affected by terrain or other obstacles
  • the 3 classes of VORs are depicted on charts as AIM 1-1-8
    1. High altitude (H)- 1,000 to 14,500 range 40 NM, 14,500 to 18,000 range 100 NM, 18,000 to 45,000 range 130 NM, 45,000 to 60,000 range 100NM
    2. Low altitude (L)- 1,000 to 18,000 range 40 NM
    3. Terminal (T)- 1,000 to 12,000 range 25 NM
  • note to determine VOR range below 1000’ refer to AIM 1-1-8 for service chart
1
Q

VOR ground equipment; this is the transmitter that broadcasts a radio signal that can be used for navigation. This facility is a cone shaped building

A

Radial:
Is a magnetic bearing outbound from the VOR station. There is one radial for each degree on the compass
Signals:
The ground station sends out 2 VHF signals. The difference in these signals is measured to determine the exact radial you are on.
1. Reference phase - signal is the same in all directions
2. Variable phase- rotates at 1800 RPMS, sends out signal on each radial

2
Q

VOR facilities

A
  • VORDME- when paired, DME is automatically dialed up the pilot does not have to dial up separate frequency for DME
  • VORTAC/TACAN- VOR co-located with TACAN. Non military pilots can get DME from this
  • sometimes a test signal can be heard it has 4 morse code identifiers
3
Q

VOR cock-pit display

A
  • OBS (omni-bearing selector) the desired course is selected by turning the OBS knob until the course is aligned
  • CDI (course deviation needle) the CDI shows angular deviation from your selected course
  • to/from indicator- this indicator shows wether the selected course will take the aircraft TO or From the station
  • to identify a VOR- select VOR frequency, push the V button, turn up the volume and listen to the morse code, it should match what you have on your chart
4
Q

RMI (radio magnetic indicator)

A
  • RMI needle always points to the station and indicates MB to the station
  • MB= what heading we would fly to actually get to the station
  • compass card moves
5
Q

HSI (horizontal situation indicator)

A
  • heading indicator superimposed with VOR and or ILS indicators
  • indicates magnetic heading of the aircraft and position of the aircraft relative to the selected course
6
Q

VOR navigation

A

Orientation your position relative to the VOR

  • put the desired VOR in corner 1 as your waypoint
  • no procedure needed to track to the VOR
  • make sure you are in VLOC mode
    1. Turn up the volume and identify the station signal (morse code)
    2. Rotate the OBS to center the CDI needle with a from indication and read the course, this tells you which radial you are on. You can also center the CDI with a TO indication to determine your direct course to the VOR
  • put in appropriate communication frequency
7
Q

VOR tracking and intercepting

A
  • select VOR frequency
  • identity the station
    1. Morse code identifier/check for any flags
    2. Sent out every 10 seconds, low pitch
  • select desired course with OBS
  • track to or from the station
  • select heading that allows a 30 degree intercept to or from the station
  • wait for CDI to center
8
Q

Display on aeronautical charts

A
  • chart shows frequency, position and morse code identifier
  • magnetic north arrowhead usually emanates from VOR
  • compass rose marked every 30 degrees
  • victor airways
9
Q

Fixing position using 2 VORs

A
  • ID position by crossing radials from two VORs in reception range
10
Q

Cone of confusion: caused by lack of signal directly over the station

A
  • display will be inaccurate- NAV flag can come down/CDI (full deflection)
  • To/from flag flips
  • fly compass heading when near the VOR (within .5 NM)
11
Q

Reverse sensing

A
  • due to pilot error needle can point the wrong way
  • back course
  • wrong heading under course index
  • wrong heading on ILS (HSI)
12
Q

VOR receiver checks (FAR/AIM 91.171)

A
  • must be inspected within 30 days for VOR to be current
  • must log SPED
    Signature
    Place
    Error
    Date
13
Q

VODGA

A

V- VOT test facility only transmits radial 360 (360 from or 180 to) error +/- 4 degrees (listed in A/FD) not a real VOR can be anywhere on the airport
O- Operator check; select a VOR radial that lies along center line of an established victor airway- then select a land mark along that radial at least 20 NM away from the station and over-fly it. Error +/- 6 degrees
D- Dual check; checking 2 separate VOR receivers (they are tuned to the same VOR station) error within 4 degrees of each other
G- ground check; specific location on the airport. Error +/- 4 degrees (listed in the A/FD)
A- Airborne; fly to a specific altitude, radial, distance over a specific landmark. Error +/-6 degrees (listed in the A/FD)

14
Q

NDB (non directional beacon)

A

The NDB is the simplest form of radio navigation. For the most part, these are just AM radio stations and a device in the air to pickup and locate those signals.

15
Q

NDB

A
  • NDB is the ground based transmitter
  • transmits radio energy in all directions
  • operates on medium frequencies (between 200 and 1750 KHz)
  • NDB classes
    1. Compass locator - 15 NM range
    2. MH class- 25 NM range
    3. H class- 50 NM range
    4. HH class- 75 NM range
16
Q

Problems which reduce NDB signal accuracy

CMINT

A

Coastal effect
- caused by the NDB signal bending slightly toward the coastline when crossing at an angle
- cross shore at mor than 30 degrees
Mountain effect:
- caused by reflections of the NDB signals from mountains
Interference:
- can come from other NDB transmitting on similar frequencies, or AM radio stations (causes needle to wander, sound clutter)
- can hear radio or morse code-needle inaccurate
Night effect:
- signals can be refracted by the ionosphere causing interference with normal NDB surface waves
- results in wandering signal
Thunderstorm effect:
- causes the needle to be deflected towards a nearby electrical storm away from the NDB

17
Q

ADF (automatic direction finder)

A
  • ADF is the name for the instrument in the aircraft
  • 3 components of the ADF
    1. The ADF receiver installed in the cockpit radio panel
    2. The antenna system
    loop antenna (think OBS):
    -rotatable
  • narrows the possibility of what direction the NDB is located down to a possibility of 2 reciprocals
    Sense antenna (think to/from flag)
  • determines which of the two possible directions is correct
    3. The cockpit display (needle always points to the NDB
    RBI (relative bearing indicator)
  • relative bearing is the angle between the aircrafts nose and the direction of the NDB
  • fixed compass rose, 360 degrees
    Rotatable card:
  • compass rose must be manually aligned with the aircrafts magnetic heading
  • gives MB without math
    RMI (radio magnetic indicator)
  • similar to HSI
  • easiest to use
  • MB shown automatically
18
Q

Navigation

A

Station identification:
- each NDB transmits its own 3 letter morse code
- the signal must be continuously monitored because there is no off flag to indicate signal failure
Intercepting/tracking/navigation:
- tune, identify and check instruments. Keep IDENT tone audible
- track TO the NDB turn to the tip of the needle
- track FROM the NDB turn to the tail of the needle
Homing:
- flying without using a wind correction angle keeping the needle on the nose of the aircraft
- flight path is going to be curved
Tracking:
- use WCA
- most effective
RMI-DME arcs:
- keep needle 10 degrees ahead or behind left or right
- as needle gets to be 10 degrees behind your left or right, turn about 20 degrees and wait for 10 degrees behind again before turning