NAV Questions

Hi all,

I've flown the Cessna 172 that comes with MSFS since Meig's Field was the default flight. I never really needed much more to play around.

Last year, I printed out some airport charts and started learning to fly IFR. I can navigate most of Georgia, USA without ever needing to look out the windows.

At some point, I "upgraded" to a Diamond with a Glass Cockpit. I've figured out how (mostly) to set up radios and use the CDI.

So, here are the questions that are bugging me:

1. KCTJ has an ILS. The Localizer is 111.7. There is no other radio beacon at the airport. I use VORTAC Lagrange and Rome to navigate in and out.

How do I know how far I am from that Airport? VORTACs give DME info, but Localizers don't. I know some places have an OMI indicator. But it seems like distance from overrun would be critical info.

2. Can I autopilot from NAV2? I want to fly a course until I intercept a radial. Then fly that radial until I intercept the glideslope. As it stands, I fly the bug (HDG with NAV armed) with the VORTAC on NAV1 active and ILS on NAV1 standby. Once I intercept the VORTAC, the autopilot does its thing. As I approach the airport, I switch back to the bug (HDG with APR armed) and flip from VORTAC to ILS.

Seems like there is an extra step in that workflow. Is there a better way?

3. Does the OBS matter on a localizer?

4. Zoom and Pan suck. No real question here. Just that FS pan and zoom gets worse with every generation. 'Member when we could put a bunch of dials and gauges on screen with a tiny little 3D window? Panning around a virtual cockpit to flip switches may be more realistic, but it sucks for practical training.

5. Can I hide the yoke? It obscures the lighting controls.

Do you have the approach plate for the airport (which you can get here)? The lower part of that plate shows that it is 3.6 nautical miles from the IAF (Initial Approach Fix and, in this case, also the FAF, or Final Approach Fix) called GPQ to the runway. Note that the ADF is required equipment for the approach, since it defines both the IAF and FAF.

1. On the lower left of the plate is a FAF to MAP table, which provides timings at specific (ground) speeds, ranging from 60 to 180 knots (interpolate between values) to travel that 3.6 NM. The only other indication of distance is if you're tuned to the LAGRANGE VOR, which it shows is 31.2 NM from the FAF, though not being in alignment with your approach path it will only give a rough distance approximation for you IF you can receive it.

But there's no need for further distance information, since you must either follow the glide slope until the time after FAF has expired or until you see the runway, if on the ILS. On localizer, you want to be at 2400 MSL crossing the FAF, then descending to 1480 MSL and no lower until the runway is in sight, or until the time runs out.

2. If the aircraft you are flying has a way to use the AP with NAV 2, then you can certainly do that, but on the NAV1 radio you can set your initial course in the active and the LOC/ILS freq in the standby (as you indicate you are doing), then just switch STBY to ACT for LOC intercept. There's no other nav facility for you to use in the NAV radios on this approach, so NAV 2 can be set wherever you like, but won't really be much help. In any case, the AP doesn't do auto switching from NAV 1 to 2.

3. No. When you tune a localizer freq, the operating mode of the NAV radio changes so that the L/R needle (CDI) is four times as sensitive as it was in VOR mode, and the OBS is disengaged, since you'll only be navigating with that freq when intercepting and flying the designed course, and more than 2.5º (if memory serves) off course there'll be no needle change until you're within that narrow range.

4. That's why I have TrackIR, so that I can move my head around in the virtual cockpit, even move fore and aft and up and down, with touching any keys or other controls. That's also why I have a HOTAS-style stick so that I don't have to hunt in the cockpit for most controls I use -- just use the button/knob on the stick or throttle for most things. Even when I freeze the TrackIR so that I can then use the pan and zoom controls, the button for that is on my stick. This allows me to keep my head outside most of the time (or monitoring the gauges if IMC).

5. Some aircraft allow that, some don't. I don't normally use the default aircraft, so don't know what they do.

Although you may be flying via NAV, not GPS, you could use the GPS to give you distance information.

The cunning pilot uses ALL the information and informatics at his/her disposal.

Hmmm -- I didn't know the sim GPS worked at all with the switch thrown to NAV.

Distance is read from the face of the instrument. All it has to have is a focus - usually an identifier for the `destination`. It does NOT need to be driving the navigation.

Plenty of YouTube videos to illustrate.

I usually fly the default 747 vc. In that an ils gives distance info. (on the hsi).

So I think ils gives distance, ils is always a combi of localiser and dme I think.

How else to know when to start the descent? Can't if no distance is known.

If you don't see the dme info in your 'hsi', then fixing may be more of a matter of finding a usefull gauge.

Or of using one that is in the aircraft already. On the default pros plane radio gauge (bendix?) is a distance info option. You can switch that to nav2 or nav1 distance. Try that.

(not at pc a.t.m. Or I would try myself first.)

I usually fly the default 747 vc. In that an ils gives distance info. (on the hsi).

So I think ils gives distance, ils is always a combi of localiser and dme I think.

How else to know when to start the descent? Can't if no distance is known.

 

If you don't see the dme info in your 'hsi', then fixing may be more of a matter of finding a usefull gauge.

Or of using one that is in the aircraft already. On the default pros plane radio gauge (bendix?) is a distance info option. You can switch that to nav2 or nav1 distance. Try that.

(not at pc a.t.m. Or I would try myself first.)

Nope -- not all ILSs have DME -- DME is a separate installation that may or may not be present.

"ils is always a combi of localiser and dme I think. " should be "ils is always a combi of localiser and glideslope.

On an ILS, you start your descent when you intercept the glideslope, but in any case (even with LOC only), you descend after the FAF (the GPQ NDB in this case), which is ALWAYS present on an instrument approach. Distance has nothing to do with it, in terms of when to start, unless it is specified as part of the approach itself (basically, as the FAF).

A "useful gauge" can't display what's not available. Take a look at the approach plate for the specific ILS/airport that the OP specified: KCTJ, here. Find any DME on that plate other than on the LAGRANGE VOR.

On ANY instrument approach, it is only legal to use DME as a defining part of the approach when it is specifically specified on the approach plate. IF a DME is available, it can be used as supplementary information when not actually part of the approach definition, but may not legally be used for defining the approach.

Do what you like in the sim, but note that the above is part of why it takes a lot of ground time, as well as flying time, to get an instrument ticket in the real world -- there's a LOT to learn, and much (most?) of it is NOT intuitive. And please don't teach others the wrong information. I used to teach this stuff, and even though that's almost 20 years in the past, not that much has changed, and certainly not that.

Addendum: Page 10-13 of the FAA's Instrument Flying Handbook starts the section on instrument approaches. There are 371 pages in this PDF, and they cover regs, weather, procedures, theory and much more. The section on approaches goes through 10-22, where Instrument Weather Flying starts.

Of course, glideslope antenna, no dme needed, must have not had coffee yet.:(

But didn't know that there are ils without dme. Good to know.

Thanks all.

So, I planned a flight from KCTJ to KJAX. FSX advised me to fly towards VNA (116.5) and then on to AMG (115.10).

I put VNA on NAV1 and AMG on NAV2. I set my bug to 140 and ALT to 5K and take off. I get into a stable flight and then arm NAV.

The first thing I noticed is that I can't actually "see" VNA. No worries, I'll just head that way and see what happens.

Well, NAV2 sprang to life shortly after. I confirmed the DME reading of 167NM. Still nothing on NAV1.

After some time, I start to question what I'm seeing/doing. Still no NAV1. I've checked and double-checked frequencies. Now I'm checking the in-game map. Still nothing.

Finally, NAV1 springs to life. At 60NM on the DME!

Do they change the power on these things?

What's the point of a flight plan where I can't see the first step after takeoff?

I'll be so glad when they invent some more reliable method of navigation...

Well, NAV2 sprang to life shortly after. I confirmed the DME reading of 167NM. Still nothing on NAV1.

You're unlikely to ever see that in the real world, rarely more than 60-80 NM.

What's the point of a flight plan where I can't see the first step after takeoff?

First, pilots are responsible for their own flight planning -- ATC doesn't do that for you. It's the pilot's responsibility to ensure that there are usable navaids where needed. You could have flown outbound from the NDB (using the ADF, of course) until getting in range of VNA. Otherwise you can look into other available VORs. This is one big reason that pilots use charts to plan flights.

When VFR, some folks may do as you did, but when IFR that isn't viable, normally, so you can sometimes have some odd routing in order to stay within range of needed navaids.

Alternatively, you could use the GPS.

I'll be so glad when they invent some more reliable method of navigation...

They have. It's called G-P-S. If you make an actual flight plan, like with the integral Flight Planner in FSX, it'll show up in the GPS.

Alternatively, plug your flight plan into an FMC. Again, another "more reliable" method of Navigation. Flying VFR? Use a AAA Atlas, and follow a highway. It wasn't so long ago a AAA Atlas and a good stopwatch, or even just a wristwatch, were the navaids.

Have fun!

Pat☺

Again, thanks all.

I'm just floundering my way through this. I will eventually learn to use the GPS. It's just that I want to know how to do it the old way.

I had read somewhere that a VOR could do 200 miles. So maybe that's total coverage? 100 miles in every direction from the station? With obstructions and conditions, I could see how 20~40% of that gets knocked off.

Thanks for all your help.

Again, thanks all.

 

I'm just floundering my way through this. I will eventually learn to use the GPS. It's just that I want to know how to do it the old way.

 

I had read somewhere that a VOR could do 200 miles. So maybe that's total coverage? 100 miles in every direction from the station? With obstructions and conditions, I could see how 20~40% of that gets knocked off.

 

 

Thanks for all your help.

Please use FSX's own inbuilt Learning Center. You've paid for it!

VOR's will vary in range from a few to very many. They are line-of-sight radio navaids so will vary in range on any given day.

You don't need to even load the sim to use FSX Learning Center. No need to flounder, FSX Learning Center is there to guide you through these basic questions, and offer interactive lessons to answer some you haven't asked.

Thanks all.

 

So, I planned a flight from KCTJ to KJAX. FSX advised me to fly towards VNA (116.5) and then on to AMG (115.10).

 

I put VNA on NAV1 and AMG on NAV2. I set my bug to 140 and ALT to 5K and take off. I get into a stable flight and then arm NAV.

 

The first thing I noticed is that I can't actually "see" VNA. No worries, I'll just head that way and see what happens.

 

Well, NAV2 sprang to life shortly after. I confirmed the DME reading of 167NM. Still nothing on NAV1.

 

After some time, I start to question what I'm seeing/doing. Still no NAV1. I've checked and double-checked frequencies. Now I'm checking the in-game map. Still nothing.

 

Finally, NAV1 springs to life. At 60NM on the DME!

 

Do they change the power on these things?

 

What's the point of a flight plan where I can't see the first step after takeoff?

 

I'll be so glad when they invent some more reliable method of navigation...

There is nothing wrong with cross country navigation under IFR using radio NAVAIDS .

You need to understand both proper flight planning preparation and the limits of the Radio NAVAIDS .

You were only flying at 5,000' , if you fly higher you will receive longer range reception .

Regards Flight planning .

Your route KCTJ to KJAX is 257.8 nm track 140 degrees .

That is a very long leg , might be OK for a fast jet , but for slower GA aircraft the route should be broken down to several legs .

When planning the flight you need either an aviation chart that has , airports , VOR , NDB showing ,

or the FS map , it has all that detail plus NAVAID frequencies .

You need to note NAVAIDS and their frequencies along that route and their distance positions so that you can use you NDB , VOR , DME to keep track of your progress.

Starting from KCTJ , it is about 30 nm to NDB EQQ (234.0) , then a further 30 nm to left off track NDB OP (339.0) , then a further 30 nm to left off track VOR/DME MCN (114.20) and NDB BEP (350.0).

Further along you had VOR NVA (116.50) .

Again futher along you had VOR/DME AYS (110.20) as Well as nearby off track VOR/DME AMG (115.10) .

As you proceeded towards KJAX you had VOR/DME CRG (114.50) about 12 nm past KJAX it would have yielded useful direction and distance information in the latter stage of your flight .

Basically you can see that you populate you Flight Plan with Radio NAVAIDS spaced along your route to enable you to check and keep track of your current position and to plot your time progress along

your route .

At the planning stage also gather destination KJAX info ,

RW 07 (059 degrees) ILS 110.70

RW 25 (239 degrees) ILS 110.30

RW 13 (119 degrees) ILS 110.50

RW 07 has a NDB JA (344.0) that can be used for approach guidance purposes , it could also be used to help with RW 25 .

Whenever you fly IFR and use NAVAIDs you are always one very busy pilot .

Cheers

Karol

There's high altitude Vor's, range 200NM.

There's also low altitude Vor's, range 40 NM I think. Not sure, may be 60.

(that distance is max distance if there are no mountains between you and the Vor to block the signal.)

range of ATIS weather broadcast is 60 NM. (again only if no mountain in the way.)

that's fsx distances.

I'll tell you what we used RW in the 1960's While flying "cross country" at regulated low altitude in low population areas such as Western Texas, Arizona, etc. We tuned in commercial "Clear Channel" AM Radio Stations.

WHAS, WLS, WLW, etc. are all examples of high powered "Clear Channel" AM radio stations which we used. All these stations are on the low end of the AM (Audio Modulated) radio band. Lower frequencies are much less line of sight and carry for a much longer distance.

Did you ever live in an apartment building and the only "music" you heard from your next door neighbor was the bass notes? How about at a stoplight? Do your windows rattle from other people's "music?" When they do, isn't that usually only the base notes you hear?

The lower the frequency, whether it be a radio or an audible frequency, the more distance that frequency travels. And the wave length is wide enough that it flows down into the valleys and goes around a ton of obstacles.

VHF and especially UHF frequencies are often used for various purposes simply because they are very directional and don't carry for a long distance. (Think how many different airports use almost the exact same ILS frequencies. They couldn't do that if they weren't high frequencies, because they would interfere with each other.)

So if we knew that WLS was near Chicago and WHAS was near Louisville, we'd tune our "ADF" radio to WLS, and write down which direction on the compass rose the needle was pointing to. Then tune to WHAS and again write down where your needle is pointed.

From Chicago you draw a straight line on your map running away from WLS at the same angle you just wrote. Then do the same from Louisville using the WHAS angle. Where the signal from WLS and the signal from WHAS intersect is about where you are. "Triangulation!"

Yes, you probably won't find many AM radio stations simmed on Flight Simulator. But if you look at the sim provided world map, you should be able to find a ton of ADF stations listed. Tune your Auto Direction Finder to those and use them in the same manner as you would if using WLS.

Triangulation is surely considered at least "Old School" in today's world. But it still works, even in flight sim and just for practice, I still use it from time to time.

Rupert

One other method we used for cross country navigating, though not helpful with a Flight Sim, was the AAA Road Maps! We always said we flew the the Hillbilly version of IFR. We called it "I Fly Roads." I, like many others I knew, joined AAA and got lots of their road maps. Especially out in those open spaces most major roads ran fairly straight and were far enough apart to be easy to recognize at the 500'-1,000' AGL we were supposed to fly.

And if you're confused about which town is what, fly a loop around the water tower. They often have the town name written on them.;) I've seen G.A. aircraft of many types and sizes do that as well.

VFR Supplements were wonderful for giving various com radio frequencies and showing where all the Restricted Areas were. We sometimes said there were more Restricted Areas in the Southwest back then than fences!!:rolleyes: But they really weren't that oriented to help those who by regulation have a hard ceiling of 1,000' AGL when flying "ferry hops."

Rupert

All interesting but taking our OP to places he doesn't want to go, or is not ready to go.

The FSX Learning Center is designed to do all this, and more. It is the core training module and should be the first port of call.

From recollection it doesn't address AM stations or the use of AAA Road Maps and their are precious few accurate roads (or towns with names on them) in the basic FSX.

So can we please stay on-point or else we'll and up talking about LORAN as well - not a nice lady we met in bar.

Our simmer is trying to learn radio navigation not remember the old days.

One other method we used for cross country navigating, though not helpful with a Flight Sim, was the AAA Road Maps! We always said we flew the the Hillbilly version of IFR. We called it "I Fly Roads."

See??? Told ya so! Neener :rolleyes: :D

Sorry, just one of those days I'm having.

Not to be a nit-picker, but actually, AM, in electronics parlance, is Amplitude Modulation. They may have started it as Audio, but as long as I've been a tweak, it's been Amplitude. As opposed to FM, or Frequency Modulation. In AM, they change the amplitude, or height of the wave transmitted. Lower frequency is used, but it takes more power to transmit with. Your transmitter has to be capable of making the amplitude, or power, of the final output to the antenna to the maximum allowed, or the signal gets "clipped" or chopped off, top and bottom, carrying less audio information that intended. The reason it picks up lightning bolts so wonderfully is that the lightning, being an electric signal, really, "adds on" to the AM signals travelling through the atmosphere. Any electrical device will do that. Car ignitions, spark plugs, alternators, power tool, you name it.

Michael (Rupert) is right about the lower freq's travelling better up over hills, down into valley's, etc.

In FM, they vary the transmitted frequency, not height, or power. You tune to the frequency in the middle of the transmitter's output, and as it varies, your receiver picks that off as audio again. That's why it's NOT affected by lightning to the extent AM is. It doesn't care the amplitude of the received signal, just the frequency. Ligtning can't change the signal's frequency. FM uses higher frequencies so each station can have a wider band of frequencies, thus giving more variety to the audio it can carry. That's why FM is, or can be anyway, stereo and AM is only mono.

FM is also used for the video signals carried between a remote video transmitter, like a blimp over a sports arena, to the main TV transmitter on the ground.

Having said all that, actually, radio shouldn't work. The transmitted signal attenuates, or decreases, at such a rate that much more than a mile or two beyond the transmitter's antenna it's so weak, receivers shouldn't be able to pick it up. That's why a lot of tweaks call it Advanced Magic, and Fricken (or another word similar...) Magic. Shouldn't work, but it does, and rather well. Magic.

Sorry, I babble...

Pat☺

Pat,

You're correct, radio probably shouldn't work. But often at night I could hear the Cubs play on WLS, the Reds play on WLW, and/or Kentucky play basketball on WHAS almost anywhere east of the Mississippi River. And often as far southwest as Arizona or Nevada as well.

Cross the mountains to the left coast and lower frequency AM radio stations there carry just as well. Plus while simming we can use various ADF signals.

So triangulation should be still doable most places for those who don't want to just use GPS even today.

One point, to clarify Pat's last post: AM broadcast radio is, indeed, on a much lower frequency than the FM broadcast radio, but aircraft communications radios are AM, that is, Amplitude Modulation, yet are very near the FM broadcast band. So the point is that either AM or FM or several other types of modulation, can be on most any frequency.

In other words, the modulation type and the frequency or frequency range are totally independent of each other. I'm not sure this was completely clear from Pat's excellent description of the way things are currently done.

The transmitted signal attenuates, or decreases, at such a rate that much more than a mile or two beyond the transmitter's antenna it's so weak, receivers shouldn't be able to pick it up.

radio probably shouldn't work

That's why receiver sensitivity is measured in microvolts, is why reception at long distance needs a high powered transmitter, and is also why larger and/or higher antennas get better reception.

And for the uninitiated, these are very simplified explanations.

That's why FM is, or can be anyway, stereo and AM is only mono.

Though I don't think it's around now, there was at one time an experiment in AM stereo -- it might have done well if FM hadn't beat them to the punch, plus it was still susceptible to all the AM interference types. I heard a little of that in the 1980s, but I didn't actually own a receiver so my experience was limited to a couple of demos. Wiki has some good info on that, BTW.

That's why receiver sensitivity is measured in microvolts, is why reception at long distance needs a high powered transmitter, and is also why larger and/or higher antennas get better reception.

Oh, I've done the math. Even with one of the tall, high-power TV transmission towers, the signal much more than 10-12 miles should be attenuated below the local noise. And AM doesn't do well with noise. It needs a relatively decent signal-to-noise ratio. With FM you can clip the noise, and filter the worst of it out, but not AM.

I'm sorry if I gave the wrong impression. You are 100% correct, in that the frequency range and the modulation type aren't in any way necessarily dependent.

Having said that, certain frequency bands lend themselves to certain applications better. Like FM needs the higher band to broadcast, since you're changing the transmitter's frequency up and down. The further you can do that, the more information it can carry on a specific channel. By the same token, if you're willing to sacrifice some of the information, you can then pack the channels closer together in a band. That's why some radios, like those on aircraft, Police, Fire, etc etc sound flat, or somewhat...bland. You're not getting the same amount of detail of the audio that you do with, say, an FM radio station.

They spaced the FM radio stations far enough apart to be able to get some very good audio information transmission. To be able to do this, they needed a higher frequency band. You can pack AM stations very closely together, since you're changing the signal's amplitude, not it's frequency. Thus, they could use a lower band. Once again, though the drawbacks are the noise that is let through the receiver's filters, because it appears to be a part of the main signal.

They made radar such a high frequency band because you don't want the signal to bend around things, like over mountains, into valleys, and so on. You want it to go straight there and back, to get accurate angular and distance information off it.

Although there are stories of fighters locking onto themselves around the entire circumference of the Earth. I understand it scared them no end. Here's a plane perfectly mimicing all your maneuvers... Just a very unique circumstance, where the radar waves were bent, but not attenuated, by the atmosphere and ionosphere, and the distance was just right to appear to be another plane nearby.

Also, different materials reflect or pass radio (radar) signals. Thus, you don't see weather (water in motion) on a radar that scans for airplanes (metal objects), and vice versa. Once they discovered the band that water absorbs, doesn't allow to pass, and doesn't reflect, but absorbs, the microwave oven was born :D

Once again, first off, you need the correct band of frequencies to do all that, and you can pack the channels relatively closely together, thus two radars near one another don't interfere with each other. There are other tricks to prevent that, as well, but they're not important here. And don't even get me started on Doppler :D

I'm sorry, I know I ramble a lot on this, but it's what I did for a living my entire life...

Pat

Hi

I'll try to stay on the OP's Topic of IFR navigation using Radio NAVAIDS .

I respect and admire your IFR use of Radio NAVAIDS in Flight planning .

It is a difficult topic to describe and cover well , I have collected some related Links on it , that are well worth reading , the material can be a little heavy , most will need to be read many times to digest the contents and concepts , but I think that they represent a good selection that will help you in your endeavours .

You will find that in reading this stuff that you will feel overloaded , don't worry about it , we all feel that way when first dealing with the subject matter , it can be confusing and overwhelming .

Just keep at it , and you will find that it slowly sinks in .

Following are the Links ,

https://www.recreationalflying.com/tutorials/navigation/other.html

http://www.campbells.org/Airplanes/VOR/vor.html

https://www.ivao.aero/training/documentation/books/PP_ADC_Navigation_instrument.pdf

https://www.ivao.aero/training/documentation/books/PP_ADC_Navigation_VOR.pdf

http://www.langleyflyingschool.com/Pages/IFR%20Groundschool--Instrument%20Navigation.html

http://wiki.flightgear.org/Radio_navigation

https://www.ivao.aero/training/documentation/books/PP_ADC_Navigation_ADF.pdf

Cheers

Karol

EDIT

If at all possible , I would recommend that you download them .

Place them in a folder so that you can read or refer back to them at your leisure .

EDIT 2

Added an ADF pdf link

How reasonable then, that the FSX Learning Center simplifies the topic, and adapts it to suit the specifics and limitations of the platform.

e.g.

https://www.youtube.com/results?search_query=fsx+learning+center

Sorry , but you do need to study (read) , and make an effort , quick and easy won't hack it ,

at least the OP displayed a determination to tackle the topic and a desire to learn about it ,

he should be thoroughly commended for his attitude .

you need at minimum the good basics .

The OP has the choice , he can take the advice of those of us that are IFR rated in Real Life , and hence have an understanding on the subject , or ignore it .

I still advocate that he read at least some of that material , better still all of it and tries to become very familiar with it .

Cheers

Karol