How to read VOR/ADF headings on the RMI?

Good evening,

 

Some aircraft have a DDRMI, like Airbus.

 

Could anyone explain me how we should read it?

 

1) If we chose a VOR and a ADF, both are VOR1 and ADF1?

2) So if I put both selector to VOR, there will be VOR1 and VOR2?

3) There are small triangles around the compass. What does that mean?

 

4) So the ADF shows us the magnetic heading to the NDB?

5) For a VOR, it will show on which course we are?

 

6) The big triangle on the top is our actual heading?

 

Thanks a lot!

1. Yes

2. Yes

3. The Cardinal and quarter compass points N, E, S, W, NE, SE, SW, NW...

4. It points at the mag heading to the NDB, but you may have to set the dial (depending on the type of instrument) to your current course to see the course to the beacon.

5. No, it shows what radial you are currently on - not your course unless the pointer is to your current course.

6. Your magnetic heading

 

DJ

Thanks a lot David!

 

1) We can select on the EFIS control panel, VOR mode:

http://www.efbdesktop.com/flight-instruments/sys-8.1.16.html

Does it show us VOR1 or VOR2? The closest?

 

2) What do you mean by: " buy you may have to set the dial [...] to see the course on the beacon"

 

Thanks a lot!

3) If we don't enter any radial, what does it show on the Navigation display in VOR mode? Because theee won't be any alignement!

Referencing the image you linked above the "alignment" to the VOR radial you chose to follow will not happen until:

1) The aircraft CONTINUES to follow the current course until the chosen radial is CROSSED (the blue line in the middle aligns with the outside blue lines and...

2) The aircraft is then turned (the aircraft symbol aligns with the blue lines while they are both themselves aligned.)

 

Note:

Blue line radial course alignment does not occur because you rotated the radial control, it aligns when the AIRCRAFT is in the proper position in the sky so the radio waves emitting in straight lines out from the VOR point directly to the VOR.

 

Think of a VOR transmitter as spokes on a bicycle wheel. The object is to follow spoke #24 or whatever compass direction you have chosen to the center. You do this by piloting the aircraft until it crosses spoke #24, then following the spoke to the center.

If AP NAV mode is turned on, the plane will turn onto spoke #24 as soon as it crosses it.

The further away you cross the "spoke", the easier the turn and track of the spoke will be.

If you get too close, you will snake ("S-turn") all over the place when using an airliner.

 

Please read the FSX Learning Center which explains this better than I just did. There is also an in-flight tutorial in the sim as well as help videos on YouTube.

 

-Pv-

RMIs point to station, regardless of it being an NDB or a VOR.

 

Some are slaved to your DG so your current heading will always be at the top of the card and the needles will always point to the bearing to the station. Others have to be manually adjusted to your heading.

 

http://en.wikipedia.org/wiki/Radio_direction_finder#Radio-magnetic_indicator_.28RMI.29

 

peace,

the Bean

Thanks a lot!

 

1) Ok, so the VOR display will change to another VOR if:

- we pass the selected radial

- if we align with the selected radial.

Do you agree?

 

2) What if you don't enter any radial? What does it show?

 

3) When the ND shows us where the VOR is, what is it showing basically? A special radial? The radial we are on?

 

4) So in VOR mode, it shows the closest VOR between VOR1 and VOR2?

 

Thanks a lot!

There is no way to select a radial with an RMI.

 

It simply points to the VOR.

 

If the compass card has been adjusted to match your heading (as I said, slaved models do this automatically) the needle will give you the heading to the VOR. You could be close to the reciprocal radial.

 

That is, if the needle is pointing at 90 degrees, you would be near the 270 degree radial.

 

The VOR display does not change stations automatically, it points to the VOR tuned to on the appropriate NAV radio, if it can hear it.

 

If the RMI is set to VOR1 it will point to the VOR that is tuned into NAV1. VOR2 reads NAV2.

 

peace,

the Bean

"1) Ok, so the VOR display will change to another VOR if:

- we pass the selected radial

- if we align with the selected radial.

Do you agree?"

 

No. By "change to another VOR : you mean change to another radial? No. The alignment lines always track the VOR you have tuned to. Whether the alignment lines line up is subject to the radial you have selected and your current aircraft position relative to the radial.

Change to another VOR frequency? No.

The VOR receiver only tracks the VOR transmitter you are TUNED to nnn.n

The receiver is able to obtain ALL the tuned VOR radials. The only difference is which one you want to align with and which one the autopilot will track.

 

Consult this section from the Learning Center:

 

Each compass point is a spoke emanating from the VOR transmitter. By setting the radial offset on your display, you are just telling the instrument which "spoke" you want to show your aircraft's relative position to. Your receiver is ALWAYS getting signals from the VOR as long as you are tuned to it and within range. See my "lighthouse" analogy below. By selecting a radial, you are asking the instrument to show you if you are South of it, or North of it, or some other compass direction. Knowing this is useful for airway navigation where you need to approach the VOR from a certain direction and leave it on a certain heading, not just point your plane at it from wherever you are.

 

"2) What if you don't enter any radial? What does it show?"

 

You ALWAYS have a radial chosen (000 is straight north.) No matter if you "enter" something or not, you have a radial chosen. It's your job to choose the best radial for the task. Two common tasks are:

1) Intercepting a radial during cruise navigation which gets you on the correct airway leaving the VOR in the right direction to intercept the next desired VOR. This is usually called "VOR Navigation."

2) Getting your plane aligned with a runway heading while approaching your destination.

 

"3) When the ND shows us where the VOR is, what is it showing basically? A special radial? The radial we are on?"

 

"ND"? Hope you are not confusing NDB for VOR. They are not the same. NDB transmitters do not have radials "spokes" and always point to the center of the transmitter. When using NDB navigation, you simply point your plane to the arrow from wherever you are.

 

Lighthouse analogy:

When you chose a radial to follow and the radial you chose and the guide line align, you have CROSSED the radial pointing to the CENTER of the transmitter. If you do not turn at this point, your aircraft will not be facing the center of the transmitter which is your ultimate goal. No such thing as a "special" radial. The VOR transmitter is like a lighthouse lamp with a bunch of shutters at each compass point so the light coming from each of the shutters can only be seen when you are facing the light from the selected shutter (radial.)

You cannot see the light coming from the lighthouse shutter which is pointing north when you are approaching the VOR from the South. My analogy breaks down a little here because your receiver can really see all the spokes, but the arrow starts working in reverse when your aircraft is not in the correct position over the earth to face the selected transmitter.

 

"4) So in VOR mode, it shows the closest VOR between VOR1 and VOR2?"

 

No, not in the way you asked the question.

You have two VOR receivers on your aircraft. They can each be tuned to separate transmitters, but each can only obtain ONE at a time (the frequency each is tuned to) In my lighthouse analogy, each radio can be tuned to ONE lighthouse, and both can be tuned to the SAME lighthouse if you want, but this is not very useful. Each radio can only obtain one transmitter and only if it's in range.

The reason you might (and skilled pilots often do) use two different VOR transmitters is to crosscheck their position by comparing two radials and distances against each other. Also, while tracking one, you can set up the other for the next VOR you want to track to make crossing them more seamless and convenient.

 

Note:

VOR is not the only way to navigate. There are other and simpler ways to navigate which as a beginning pilot you should learn first. Save VOR for later when you have gained a lot of confidence in navigation.

 

One way to learn is to use a flight plan and the GPS to control your flight. While flying under NAV/GPS control, tune to varius VOR frequencies along your path and watch the display while selecting different radials. If the VOR is in front of you and to the right while you are heading North, you will use radials between 000 and 90 and when you cross the radial you selected, you will see the needles align then drop away again. The alignment moments are the heading you turn to the point your aircraft directly at the VOR. After a few flights doing this, a light will click on and what I've explained so far will begin to make sense.

 

VOR navigation is not easy for someone who does not have refined map skills or the ability to IMAGINE in your mind a picture your place in the sky as a place on a map AND at the same time, see VOR "spokes" as roads you turn onto to get to the center of the VOR instead of trekking through the woods. While using the GPS map, you can see the location of nearby VORS and the needles will begin to make sense.

 

-Pv-