Any old timers fly "A's & N's" ?

Kritchlow

Kritchlow

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Kritchlow
I'm fascinated by early forms of navigation. I have read as much as possible about the yellow arrows, and beacon lights.

Before VOR's, which I *believe* were introduced in the 40's (and before NDB's?), there were the A's and N's. Probably nobody here actually used them for navigation, but I want to learn as much as possible about that form of nav. I was able to find some early charts...

For the younger people here, it was a Morse code thing. A was ._ , and N was _.

(Heck, I may have that backwards!!)

Anyway, if you heard a constant tone you were on course. A little more "A" meant left of corse. A bit more "N" right of corse (again, possibly backwards).

Does anyone have any info to add too this? I find it totally amazing.
 
Right and left for A and N depended on which quadrant you were in and which direction you were flying. Never flew one.
 
I'm too much of a newbie to have flown one, but I did learn about them in private pilot ground school. The "N" quadrant was the one that included north (true?/magnetic?). The Sanderson film strips had an audio record that played the 'off' and 'on course' sounds for comparison. We also learned about "bone markers" and "fan markers". That was when I used to tag along with my dad when he was learning to fly, late 1950s early 1960s.

dtuuri
 
I think you might still find a fan marker or two around. The A/N stations are long gone.
 
When you were on the course line, the audio A and N overlapped into a solid tone. Really kind of clever.
 
I think one of the A& N routes became Victor Airway 6, from NYC to SFO. Before A&N, along that route there were beacon lights mounted on towers, which rested on concrete pads that had arrows to show the way in daytime. Some of the pads and the beacon towers still exist, even if the A&N radios that replaced them do not.
 
Kritchlow said:
I'm fascinated by early forms of navigation. I have read as much as possible about the yellow arrows, and beacon lights.

Before VOR's, which I *believe* were introduced in the 40's (and before NDB's?), there were the A's and N's. Probably nobody here actually used them for navigation, but I want to learn as much as possible about that form of nav. I was able to find some early charts...

For the younger people here, it was a Morse code thing. A was ._ , and N was _.

(Heck, I may have that backwards!!)

Anyway, if you heard a constant tone you were on course. A little more "A" meant left of corse. A bit more "N" right of corse (again, possibly backwards).

Does anyone have any info to add too this? I find it totally amazing.
Click to expand...

Low frequency Radio Range. The legs were arranged to form the 1930s, 40s, and even 50s airway structure in the U.S. Instrument approaches could also be flown on stations near an airport. ADF could be used on some of them, depending on the installation. They started phasing them out in the late 1950s. The FAA left one operating at Elkins, West Virgina as a museum piece of sorts. But, the budget caught up with it and it was shut-down late 60s or early 70s.

It was a terrible form of navigation, especially when there were lots of TRWs around.

The instrument rating ride of the 1950s included ILS, VOR and L/F Range.

Attached is an old O'Hare NDB chart. Although it isn't a L/F Range procedure, several range stations are depicted on the chart.
 

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NoHeat said:
I think one of the A& N routes became Victor Airway 6, from NYC to SFO. Before A&N, along that route there were beacon lights mounted on towers, which rested on concrete pads that had arrows to show the way in daytime. Some of the pads and the beacon towers still exist, even if the A&N radios that replaced them do not.
Click to expand...

V6 went (and still does go) to OAK. SFO was not an important airport before WW2.

Even many of the local pilots don't realize the building atop Mt. Diablo is the penultimate lighted beacon on the first transcontinental air mail route, now V6.

Some old VOR CDIs are still labeled A and N.
 
When I took ground school, in 1969, the Sanderson Private Pilot Course that we used included information about four-course range approaches and the written had some questions about them. There was still a range station at HLN, which we were told was the last operational one in the country. If I can find it, I have a Butte sectional from the late '60s that shows the HLN range (and, yes, I know there is no Butte sectional; there was 50 years ago).

The airway beacons were still being used at that time, as well. Today, the Aeronautics Division of the MT Dep't. of Transportation still maintains the beacons in a couple parts of the state. Years ago, I flew over
Wolf Creek Canyon, between HLN and GTF at night. It was clear and a million and the beacons were highly visible. A first generation HUD. :rolleyes:

In 1962, the Governor of MT was killed when the ANG C-47 which was taking him back to Helena crashed in Wolf Creek Canyon while trying to follow the beacons in a storm. To this day, if you're driving on I-15 and need to relieve yourself, you can stop at the Donald G. Nutter Memorial Rest Area, located below the ridge where the gov's plane went down. I don't know how many governors who died on the job are commemorated with a rest stop. I'm guessing not many.

Mark
 
Kritchlow said:
Before VOR's, which I *believe* were introduced in the 40's (and before NDB's?), there were the A's and N's. Probably nobody here actually used them for navigation, but I want to learn as much as possible about that form of nav. I was able to find some early charts...
Click to expand...

The first Very High Frequency Omnidirectional Radio ranges were commissioned in 1946 or 1947, sources vary. The first Victor airways were put in operation in 1950 or 1951.

NDBs preceded VORs. I can't say exactly when, but they can be found on aeronautical charts prior to 1945.

The last L/MF Radio Range in the US was in Alaska, 1974.
 
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MAKG1 said:
V6 went (and still does go) to OAK. SFO was not an important airport before WW2.

Even many of the local pilots don't realize the building atop Mt. Diablo is the penultimate lighted beacon on the first transcontinental air mail route, now V6.
Click to expand...

The V (Victor) stands for VHF airway. VORs are VHF. The old L/F airways carried one of four colors as their designation. Two were for north/south. I don't recall which was which.

Some old VOR CDIs are still labeled A and N.
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I never saw that. What purpose would it have served? A lot of the earlier VORs had yellow and blue for the localizers and for a briefly-lived system, the four-course VHF range station. LAX had one of those.
 
When I was in USAF Nav school in 1975 they taught us about the four course ranges, because there were still a few of them out somewhere in the world.

We did use the CONSOLAN system in our T-29s, which was very similar the A-N system, except it was a 360 degree system.
 
aterpster said:
Attached is an old O'Hare NDB chart. Although it isn't a L/F Range procedure, several range stations are depicted on the chart.
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I have a 1949 vintage Michigan state aeronautical chart. It's a sectional type chart on one side with an airport directory and eleven approach plates on the other side. They're all range station approaches. I've attached scans of two of the approach plates as well as the Detroit area inset.
 

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And I thought flying the NDB could be tricky. I read about A N nav but never had the chance to fly it.
 
So glad to hear people interested in this kind of aviation history! (I would hate for us to lose touch with how we got where we are.) I too studied the AN radio range topic a while back and it is fascinating; it would have been neat to experience this even once. There is a video that covers the basics of this, in it they say they used them for enroute nav as well as approaches....down to 300' minimums! 10 minute video in which you can see a depiction of the airplane going around a beacon (ignore that it is traveling the wrong way - it still gives the idea) and you can hear the signal, see the positional relationship of the airplane to the beacon.
David Franz's yt video here.
https://www.youtube.com/watch?v=p-VqtNY8vpw
 
aterpster said:
The V (Victor) stands for VHF airway. VORs are VHF. The old L/F airways carried one of four colors as their designation. Two were for north/south. I don't recall which was which.



I never saw that. What purpose would it have served? A lot of the earlier VORs had yellow and blue for the localizers and for a briefly-lived system, the four-course VHF range station. LAX had one of those.
Click to expand...

If you compare the transcontinental route to V6, you'll find a match. It wasn't called that, but it's the same route.

I can't answer the why. I've seen a CDI, in a museum, clearly labeled VHF as well as A and N.
 
aterpster said:
The V (Victor) stands for VHF airway. VORs are VHF. The old L/F airways carried one of four colors as their designation. Two were for north/south. I don't recall which was which.
Click to expand...

Green and red were east-west, amber and blue north-south.

Civil Airways of he United States

I never saw that. What purpose would it have served? A lot of the earlier VORs had yellow and blue for the localizers and for a briefly-lived system, the four-course VHF range station. LAX had one of those.
Click to expand...
That was VAR, Visual Aural Range.

I thought the blue and yellow arcs were a good thing for localizers. Whether on back course or front course, a displaced needle in the colored arc on your CDI indicated the aircraft was in that same color of the localizer.
 
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JimNtexas said:
When I was in USAF Nav school in 1975 they taught us about the four course ranges, because there were still a few of them out somewhere in the world.

We did use the CONSOLAN system in our T-29s, which was very similar the A-N system, except it was a 360 degree system.
Click to expand...

Do you know if they still teach celestial navigation at Nav school?
 
Gucci Pilot said:
Do you know if they still teach celestial navigation at Nav school?
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My understanding is that the Air Force no longer has 'navigators', they have 'Combat System Operators'.

I'm pretty sure that celestial is not part of the core CSO syllabus, but I suppose students going to one of the few transport type platforms that still have a small-n navigator crew position might still learn celestial, but I don't know.
 
I've never actually used that system, but my Dad did, I'd listen to the tones when i was a kid riding along in his SR10 Reliant.
 
write-stuff said:
When you were on the course line, the audio A and N overlapped into a solid tone. Really kind of clever.
Click to expand...

And over where the radio tower was is called "a cone of silence". I asked my 80 year old helo CFI and he said he flew them regularly a long time ago. They actually worked quite well at the time.
 
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Geico266 said:
And over where the radio tower was is called "a cone of silence". I asked my 80 year old helo CFI and he said he flew them regularly a long time ago. They actually worked quite well at the time.
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Until they realized that loss of signal was a poor indicator of station passage and installed Z markers in the cone.
 
Not an old timer, rather i'm gen-x, but yes i've flown them when i started flying ~1990
 
JHW said:
central africa. They also had DME-only approaches with no course guidance, something I assumed was normal at the time.
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In DME inward-spiraling mode? Like a Boa Constrictor? I guess given the locale, it would make sense. :wink2:
 
RotorDude said:
In DME inward-spiraling mode? Like a Boa Constrictor? I guess given the locale, it would make sense. :wink2:
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I guess there were lots of techniques, I tended to fly them as a sort of elliptical holding pattern getting lower as you approach the station, then climbing as you get further away, but with no formal "approach" vs "missed approach"
 
The 4 course range and headphones allowd the pilot to fly without needing a meter instrument. So it was simpler and less expensive. Those old instruments were heavy too.
 
Lots of great info here... Thanks!!
 
Celestial navigation. Its easy to pick a star and follow it. Dont even need the name of the star. Of course you initially need to be able to point yourself in the right direction.
 
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