I'm Confused. Why So Many Navigation Types?

D

DR750S

Pre-takeoff checklist
Joined
Mar 22, 2018
Messages
135
Display Name
Display name:
DR750S
Hello!

This thread was inspired by DenverPilot's "And away goes VOR/DME RNAV...." thread.

Why so many?

I'm going to be new student pilot soon. I'll be purchasing my training aircraft (in case you have not seen my first thread, check it out and offer your thoughts on my question) and my time building aircraft, a twin turboprop. One the things that began concerning me as I started my study into buying an aircraft had to do with how the aircraft is equipped with avionics. The type and kind of avionics seems to determine a lot about what kind of IFR flying you can and cannot do - particularly with respect to Navigation and Approaches.

After reading DenverPilot's OP title, it struck me as odd that there are so many different Navaid Types. It then dawned on my that such an array of Navaid Types are probably what also leads to instrument panel clutter. I'm still fairly green, so that last statement might not be true - but that's why I'm asking the question, to find out.

VOR, DME, RNAV - heck I thought RNAV was fairly new! I've heard of LPV, GPS, Localizer, etc., etc., and I've always wondered, why so many? What's the point? I then had the thought that an airspace system that had no back-up was not very safe, so I blamed it on the need for back-up Navaids. But, then I thought, why not just have one type of Navaid and then fill the airspace system with back-ups that support that kind of Navaid. Its just confusing right now for me, personally. I'm sure it will all sink in at some point.

Is this a regional issue. Are there only certain types of Navaids located in certain parts of the country that caused the initial proliferation of so many different Navaid Types in the CONUS? Or, was this a technology issue. Did the world of aviation spin-off multiple types of Navaids as a direct result of competing technologies, or the innovative spirit of engineers, or by way of regulatory requirements?

I have so many questions about Navaids that its not even funny. Or, maybe it is funny, but I should not be laughing because I've got to figure this stuff out sufficient to pass my first DPE check-ride!:eek:

Again, what's the point. Doesn't GPS effectively obsolete just about everything else, or am I way oversimplifying the matter entirely? Seriously, how much of this glut of Navaid Types will we be flying, say 20 years from now?

Thanks!
 
The answer is "history". As technology progresses, we add more sophisticated types of NAV aids. Some old ones are decommissioned, but there is always overlap of technologies.

VOR, DME, Localizer, and ILS(localizer with glide slope) are basically the same technology now being slowly replaced by GPS(which is a specific type of RNAV). ILS is still super useful, however. But expensive. LPV(a type of GPS approach) is a more sophisticated GPS-WAAS technology which also takes ground station information. This is a current "state of the art".
 
genna said:
The answer is "history". As technology progresses, we add more sophisticated types of NAV aids. Some old ones are decommissioned, but there is always overlap of technologies.

VOR, DME, Localizer, and ILS(localizer with glide slope) are basically the same technology now being slowly replaced by GPS(which is a specific type of RNAV). ILS is still super useful, however. But expensive. LPV(a type of GPS approach) is a more sophisticated GPS-WAAS technology which also takes ground station information. This is a current "state of the art".
Click to expand...


So, is the system getting closer to a single Navaid, that being GPS or GPS variants working in tandem with each other? Also, if buying an airplane for the purpose of cross-country flying in all (safe) weather conditions day and night, do I need to be concerned to any meaningful degree about the age/type of avionics on-board (aside from the obvious, that if flying IFR, the aircraft needs to be IFR equipped)?

Also, does this put something like Garmin's Avionics product line directly in the sweet spot. Meaning, it can be adapted, configured and arranged to meet the needs of today and with its LRU implementation, can be re-adapted, re-configured and re-arranged to meet the needs of tomorrow? Or, gain, am I oversimplifying things?

Thank you for the reply.
 
It's a marketing ploy.
Which preys upon the well known pilot weakness for new Gadgets!
 
Single navaid, such as GPS? ok, do you trust your life to a single pount of failure? To the fact that GPS can be spoofed? That there are places where GPS fails? One local example is the 400 ft agl off the
departure end of 26 at Front Range (FTG) which is 5 nm SE of DIA/DEN.

Multiple navigation avionics means redundancy in event of failure of one type of navigation.
 
murphey said:
Multiple navigation avionics means redundancy in event of failure of one type of navigation.
Click to expand...

So, is the redundancy a fluke? Or, was redundancy planned so as to mesh with genna's post above about the number of so many different types of Navaids being a function of historical, overlapping innovation in advanced technology?
 
As long as you are a /G that can shoot a RNAV and a ILS its all good.


Side note debated installing a TACAN in my 185 when I saw one come up for sale.
 
N659HB said:
Google LORAN while you're at it! ;)
Click to expand...


Thanks, I did. Having just looked at it from a purely technology standpoint, it seems cumbersome and high maintenance to manage for wide area navigation purposes. However, for strictly Approach purposes (and, I don't know if LORAN was ever used exclusively for this purpose) it would seem to have some advantages, if the transmitting stations were clustered correctly near the airport. The LLoP calculations of the LORAN seem fairly straight forward and it does appear to work down to sea level. The Cost Guard used to operate it. The President and the Congress tried to kill it back in 2009, or so. I don't see companies like Garmin, Avidyne, etc., with products that support it.

Is LORAN completely done?
 
James331 said:
As long as you are a /G that can shoot a RNAV and a ILS its all good.


Side note debated installing a TACAN in my 185 when I saw one come up for sale.
Click to expand...



I had to thrash google on your post. Remember, I'm new at this and just getting up to speed. I've got a long way to do. What I found was:

Global Navigation Satellite System (GNSS), including GPS or WAAS, with enroute and terminal capability.
Click to expand...

This seems to conflict somewhat with murphey, above. Unless, a /G equipped aircraft also contains other non-GPS related instruments on-board. Should I assume that would in fact be the case with a /G equipped aircraft? It would seem to make sense. Discontinuance of VOR Service by FAA here: https://www.faa.gov/air_traffic/flight_info/aeronav/acf/media/Presentations/12-01_Discon-of-VOR-update.pdf. TACAN was listed (by way of reference) in the above document.

When I start doing Flight Planning, will I be able to figure out Waypoints en route using strictly GPS and/or WAAS? Or, will those Waypoints include other Navaids such as the VORs which the FAA is apparently leaving in tact. Moreover, what defines what a Waypoint consists of anyway? Can a Waypoint be any Navaid? And, what if my aircraft does not have the required equipment to pick-up that Waypoint/Navaid - do I just select another nearby Waypoint on the chart, or rearrange my entire flight plan after running into that same scenario multiple times (not enough Waypoint/Navaids that match my equipment)? Or, does GPS on-board simply cancel out the need for Waypoint Navigation because you are flying direct? And, what about when/if ATC redirects me to something that my aircraft does not have sufficient equipment on-board to use - or would that simply never happen?

Regarding TACAN. Isn't that used by the Military, where a VORTAC is used by us Civilians? Lastly, with the FAA shutting down VORs and VORs are the kingpins of VORTACs, would you still install such equipment?

Now, you know why I say that I'm somewhat confused by all this Navaid Soup. Also, as a design engineer (systems engineer) myself, I'm having something of a hard time understanding why no one has cleaned-up this system before now. Any ideas on what's going on there? It seems a little weird as a functional system, for lack of a better definition. I mean, stuff works - but it seems so sprawling with diversity all manner of dissimilar maintenance requirements to keep it all going. Or, is this just the way it is in GA?
 
N659HB said:
LORAN is still used for shipping, i.e. ocean ships, I believe.
Click to expand...


Thanks. That tells me what I need to know. In other words, I won't be worrying about learning it as a GA pilot, nor installing equipment for it in my airplane. Ok, that's one down and apparently a billion more Navaids to go! Anybody got a book reference that covers all Navaids and that covers what the government is doing about terminating or keeping them. That would be very helpful. I'm trying to wrap my head around the Navaid Concept before training begins.

Also, any recommendation on whether FSX or X-Plane 11 would be good for initial introduction to using Navaids before actual flight training begins? My concern here is that I get into an airplane with my Instructor, become so overwhelmed with "Stuff" like this and not being able to focus on the basics of how to properly handle an aircraft and keep in flying. I don't want to put the cart before the horse. But, I also don't want the horse running away without the cart either.

There's so much to learn and I have a lot of excitement. But, right now, the whole Navaid thing and the on-board equipment it requires seems strangely hobbled together in a kind of piecemeal fashion, quite honestly. I'm not complaining. It is just that being an engineer myself, I tend to see "systems" as being designed with apparent strategic intent. In other words, you can fly an approach to KABC using VOR/DME (which is being phased out primarily by the FAA). And, you can fly an approach using LPV to KDEF. Both will require two completely different kinds of on-board technology in the form of Instruments and/or Equipment. That just seems weird. I don't know, maybe I'm weird for thinking its weird. I have no idea right now.

Its gonna be an interesting learning process!
 
One thing I wish that existed that would have made my IR training much easier was just a simple list of all the types of approaches and what they generally mean, in summary format.. I felt like this was only haphazardly covered in Kings, and the FAA publications, and they kind of just expect you to figure out by studying a myriad of approach plates and doing the research

Knowing the ins and outs of all of these up front to study off as flashcards or something would have really helped. Especially knowing the reasons for the differences and how they impact DA/DH/MDA, etc.

LNAV
LNAV+V
LNAV/VNAV, baro VNAV
LPV
LP
Stand-Alone GPS
PAR
ASR
VOR
ILS
LOC
NDB
Circling
Visual
..oh, and an explanation of why the additional letters at the end. Like why is Gillespie (SEE) localizer approach called a LOC-D. I later learned why this was, but I can almost guarantee that most people walkout out of the testing room after passing the FAA written would not be able to break all that stuff down above that well

I ended up figuring all of this out and learning it, but it takes a lot of sleuthing. Try Googleing "list of approach types" and you get a lot of basic beginner type stuff, or stuff that doesn't help answer the questions at all

Also, I find some irony that a type of navaid designed back in the 5th century BC (or, BCE for the secular people here) is still being used today to guide airliners
upload_2018-3-22_18-59-35.png
 
DR750S said:
seems strangely hobbled together in a kind of piecemeal fashion
Click to expand...
Yeah, when I started my IFR training I had this expectation that the IMC world was super deliberate and precise.. and don't get me wrong, IT IS, but the way they do it is incredibly hokey. Have you seen a DME arc? You literally fly a giant circle staring at your DME while gently turning the plane and incrementally moving the OBS so continue to intercept the radial as you change it, in order to fly the arc. When I first learned about that, and flew it, I was amazed at how ridiculous that was. It seriously made me feel like I should just whip out my sextant and abacus and start doing calculations

DR750S said:
maybe I'm weird for thinking its weird
Click to expand...
You are not weird at all. It drives me nuts. Luckily, we're moving more and more toward GPS type systems and the mess seems to be cleaning itself up.. as others said though, I think as technology advanced you saw new systems get born, but due to costs, etc., old systems stayed alive for reasons XYZ..
 
You're starting out at the beginning. Don't worry about the many different and diverse methods of navigation. You'll start with paper (a map), a pencil, a watch (for timing) and a compass. Understand that, become comfortable with that, then you'll be introduced to other forms of navigation. Most of the other forms are for instrument navigation. You'll have a tiny bit of that as a student pilot but until you get to the private pilot (ASEL) no need to worry about it right now.

As for buying the airplane now, I and probably most people here would highly recommend that you start lessons in whatever is available at the flight school and get familiar with the basics of aviation, aerodynamics, navigation, weather, etc. Give it a few hours (or more) and you'll have a better idea what you want in the airplane intend to buy. You don't buy a Maserati to learn to drive. Or an 18-wheeler. Same principle applies to aviation. IPT (Initial Pilot Training) in the Air Force starts with single engine aircraft. They don't throw the newbies into F22s.
 
The more “advanced” the nav systems get the less robust and vulnerable they become.
 
Most modern commercial aircraft can't even fly an NDB approach anymore, unless it is an overlay, not that there many left anyway. Thirty or forty years ago VLF/Omega was the primary nav system. After a seven hour oceanic crossing you would be lucky to coast in within 20-30 miles of where you thought you were. Then came the INS or inertial nav system, basically it used gyros and accelerometers to determine position. It was similar to what was being used on nuclear subs.

It allowed you to coast in within about 5-10 miles of where you thought you were. INS would update it's position whenever it received a VOR or DME signal. You could tell you were getting close to the coast in point when the airplane would make a gentle turn after an update.

Big airplanes still use INS but now it is updated continuously by GPS. It is so accurate that we actually offset to the right 1 or 2 miles for lateral clearance from traffic above us for wake turbulence avoidance. It is called SLOP (no really) it stands for Strategic Lateral Offset Procedure and is actually required when oceanic.

Loran was never used that much in commercial aviation because the signal would tend to go away when in the clouds.

VOR nav is being phased out today just as NDBs a few years ago and the really old A-N ranges from the thirties. Europe usually leads the way and has been decommisioning VORs for a number of years and I believe all of their NDBs are long gone. Satnav and satcom are here to stay, as are ADS-B and ADS-C.

I realize that general aviation aircraft don't usually have long range nav equipment, my point is that things continually get better. Old stuff gets phased out and replaced with better stuff. GPS is much more reliable than any NDB or VOR ever was and more accurate as well.

The only thing in my Cessna 180 is GPS.
 
DR750S said:
Thanks. That tells me what I need to know. In other words, I won't be worrying about learning it as a GA pilot, nor installing equipment for it in my airplane. Ok, that's one down and apparently a billion more Navaids to go! Anybody got a book reference that covers all Navaids and that covers what the government is doing about terminating or keeping them. That would be very helpful. I'm trying to wrap my head around the Navaid Concept before training begins.

Also, any recommendation on whether FSX or X-Plane 11 would be good for initial introduction to using Navaids before actual flight training begins? My concern here is that I get into an airplane with my Instructor, become so overwhelmed with "Stuff" like this and not being able to focus on the basics of how to properly handle an aircraft and keep in flying. I don't want to put the cart before the horse. But, I also don't want the horse running away without the cart either.

There's so much to learn and I have a lot of excitement. But, right now, the whole Navaid thing and the on-board equipment it requires seems strangely hobbled together in a kind of piecemeal fashion, quite honestly. I'm not complaining. It is just that being an engineer myself, I tend to see "systems" as being designed with apparent strategic intent. In other words, you can fly an approach to KABC using VOR/DME (which is being phased out primarily by the FAA). And, you can fly an approach using LPV to KDEF. Both will require two completely different kinds of on-board technology in the form of Instruments and/or Equipment. That just seems weird. I don't know, maybe I'm weird for thinking its weird. I have no idea right now.

Its gonna be an interesting learning process!
Click to expand...


"Enhanced LORAN" is in the works. Its accuracy is equal to that of GPS according to flight tests. No apples-to-apples comparison with legacy LORAN. All new equipment will be required. Congress mandated a ground-based backup to GPS and this is it. At the age of 89 I will never live to see it in action.

Bob, USCG-Ret, skipper of two LORAN stations back in the day.
 
Stickman said:
Then came the INS or inertial nav system, basically it used gyros and accelerometers to determine position
Click to expand...
Thanks for the detailed write up

INS always amazed me.. incredible that a mechanical device has the capability to be that accurate just by internally sensing where it's position has changed based on the accelerations placed upon it
 
There's always the old 4-course radio too, that'll keep you up at night.
 
DR750S said:
I had to thrash google on your post. Remember, I'm new at this and just getting up to speed. I've got a long way to do. What I found was:



This seems to conflict somewhat with murphey, above. Unless, a /G equipped aircraft also contains other non-GPS related instruments on-board. Should I assume that would in fact be the case with a /G equipped aircraft? It would seem to make sense. Discontinuance of VOR Service by FAA here: https://www.faa.gov/air_traffic/flight_info/aeronav/acf/media/Presentations/12-01_Discon-of-VOR-update.pdf. TACAN was listed (by way of reference) in the above document.

When I start doing Flight Planning, will I be able to figure out Waypoints en route using strictly GPS and/or WAAS? Or, will those Waypoints include other Navaids such as the VORs which the FAA is apparently leaving in tact. Moreover, what defines what a Waypoint consists of anyway? Can a Waypoint be any Navaid? And, what if my aircraft does not have the required equipment to pick-up that Waypoint/Navaid - do I just select another nearby Waypoint on the chart, or rearrange my entire flight plan after running into that same scenario multiple times (not enough Waypoint/Navaids that match my equipment)? Or, does GPS on-board simply cancel out the need for Waypoint Navigation because you are flying direct? And, what about when/if ATC redirects me to something that my aircraft does not have sufficient equipment on-board to use - or would that simply never happen?

Regarding TACAN. Isn't that used by the Military, where a VORTAC is used by us Civilians? Lastly, with the FAA shutting down VORs and VORs are the kingpins of VORTACs, would you still install such equipment?

Now, you know why I say that I'm somewhat confused by all this Navaid Soup. Also, as a design engineer (systems engineer) myself, I'm having something of a hard time understanding why no one has cleaned-up this system before now. Any ideas on what's going on there? It seems a little weird as a functional system, for lack of a better definition. I mean, stuff works - but it seems so sprawling with diversity all manner of dissimilar maintenance requirements to keep it all going. Or, is this just the way it is in GA?
Click to expand...

You still have waypoints with GPS, they just don't need to be based on any ground navigation equipment(though they often are). Lots of them are just made up points on the chart(often intersections of some routes or significant points on approaches). WAAS GPS is realistically all you need today. These are the most common approaches around. But you really want redundancy. Especially flying IMC. Some have dual GPS, but at least one LOC/GS receiver(for ILS/LOC/VOR) is still pretty useful i think. ILS is not going away for a while i think. It's my understanding that there are many older commercial birds that do not have very up-to-date GPS equipment. $$$$$ For some airports, sometimes GPS(LPV) is better, often it's not available or ILS is simply better. It all depends where you fly.
 
Tantalum said:
INS always amazed me.. incredible that a mechanical device has the capability to be that accurate just by internally sensing where it's position has changed based on the accelerations placed upon it
Click to expand...
IRUs are no longer mechanical. They use laser-ring gyros that sense acceleration by measuring the red or blue shift of the laser beam.

https://en.wikipedia.org/wiki/Ring_laser_gyroscope

The INS positions (there are either two or three IRUs onboard) are not updated. The FMS takes input from the IRUs, DME/DME, and GPS (if installed) to compute its position (again, two or three FMS units on board, each with its own calculated position).

Still quite a few airplanes flying around without GPS. Many of the 767s flying cargo are pre-GPS.
 
I didn't read all of the posts so this may have been said but, I think another reason there are so many different kinds navaids is because there are a lot of planes out there that still rely on a lot of the old systems. For example, we have an airplane that does not have GPS. If the government shut down VOR's and NDB's, we would have no IFR navigation. And as much as I'd like to have GPS capability, I don't have an extra $20,000 lying around.
 
lancie00 said:
And as much as I'd like to have GPS capability, I don't have an extra $20,000 lying around
Click to expand...
Genuine question, but does a 430 install really cost $20K? I thought you could get a 430 for a few thousand?
 
Tantalum said:
Genuine question, but does a 430 install really cost $20K? I thought you could get a 430 for a few thousand?
Click to expand...

430W (WAAS) will be more than a non-upgraded 430. And they’re in high demand as they’re cheaper than the GTN series but not by much. Labor and other misc parts (including the proper WAAS or no-WAAS GPS antenna) will be roughly double the price of the unit by itself at most avionics shops. Install ain’t cheap.

Since install and labor don’t really go any higher with the GTN, the delta is usually only the unit price. Which is why we went GTN. Plus the age of the 430/530 which could lead to maintenance issues sooner than the GTN should. But then again, touchscreens can become problematic so we shall see.

In the end, for us, the GTN 650 was reasonable. The 750 price jump wasn’t worth it to us with adding the Flightstream 510 for iPad integration. Can buy a big iPad for cheap. :)

And frankly spinning the knobs on the 430/530 feels really klunky after trying out the GTN touchscreen. It’s a preference thing, but I’m enjoying the touchscreen more. Silly thing will even do pinch-zoom after a particular software release, just like the iPad.
 
bobmrg said:
"Enhanced LORAN" is in the works. Its accuracy is equal to that of GPS according to flight tests. No apples-to-apples comparison with legacy LORAN. All new equipment will be required. Congress mandated a ground-based backup to GPS and this is it. At the age of 89 I will never live to see it in action.

Bob, USCG-Ret, skipper of two LORAN stations back in the day.
Click to expand...
Was this one of yours? Near Carolina Beach, NC? I was flying over this field one day, and wondering, what the heck is it. So I used google maps to look at the street view of the entrance and it was a Coast Guard gate. Eventually figured out(I think) it was a retired LORAN site.

upload_2018-3-23_22-48-6.png
 
denverpilot said:
And frankly spinning the knobs on the 430/530 feels really klunky after trying out the GTN touchscreen.
Click to expand...
I hear you! There's a '76 Archer I fly with a GTN, I recently rented an older Avidyne 430 SR20 and it actually felt much more "low tech" than the Archer

The G1000 Perspective is nice, but that GTN is a slick and very smart unit. Garmin did a great job with it
 
exncsurfer said:
Was this one of yours? Near Carolina Beach, NC? I was flying over this field one day, and wondering, what the heck is it. So I used google maps to look at the street view of the entrance and it was a Coast Guard gate. Eventually figured out(I think) it was a retired LORAN site.

View attachment 61231
Click to expand...

St. Paul Island, Alaska, in the middle of the Bering Sea; Gesashi, Okinawa.

Bob
 
Tantalum said:
LNAV
LNAV+V
LNAV/VNAV, baro VNAV
LPV
LP
Stand-Alone GPS
PAR
ASR
VOR
ILS
LOC
NDB
Click to expand...

And there’s MLS, microwave landing system, but it was decommissioned at its only airport, Heathrow, a year ago.

It was intended to replace ILS, but then GPS came along.
 
bobmrg said:
"Enhanced LORAN" is in the works. Its accuracy is equal to that of GPS according to flight tests. No apples-to-apples comparison with legacy LORAN. All new equipment will be required. Congress mandated a ground-based backup to GPS and this is it. At the age of 89 I will never live to see it in action.

Bob, USCG-Ret, skipper of two LORAN stations back in the day.
Click to expand...


eLORAN has been talked about for a long, long time. I seriously doubt it will ever come to anything, but there are a few vocal entities out there still trying to make it happen.

I was stationed at CG Navigation Center when we shut LORAN down. Also did my year on Attu Island, AK in the mid '90s.
 
My two methods: GPS, and back-up GPS.

The back-up is really my primary...iFly 740, which displays all the sectionals and TACs, and has ADS-B in via a Ping receiver.

If I had a failure of one or both, I'd grab the paper sectional out of the map box. Keep those pilotage skills sharp! :D
 
NoHeat said:
And there’s MLS, microwave landing system, but it was decommissioned at its only airport, Heathrow, a year ago.
Click to expand...

Didn't they have one installed somewhere in the states? For some reason I'm thinking Minnesota somewhere.
 
mscard88 said:
Didn't they have one installed somewhere in the states? For some reason I'm thinking Minnesota somewhere.
Click to expand...
Hailey Idaho (Sun Valley) had one for a while. The plate said for Horizon Air DHC-8 aircraft only on it. I have no idea if it is still being used.
 
You must log in or register to reply here.
Back
Top