Fan Marker... How to fly?
- Thread starter asicer
- Start date
RussR
En-Route
I used to have access to historical copies of the AIM (actual paper versions), and I looked this up maybe 15 years ago. The references to various types of markers were removed in about 1995-1997 as I recall. So if you find an AIM from that time period or earlier, you can read about them. They were used on airways as well as approaches. Regardless, they were all 75 MHz marker beacons, so you'd receive them on your standard marker beacon receiver.
I think there were the following types:
- Low powered fan
- High powered fan
- Z
- Dogbone
The first two are fairly obvious what the difference is, but the others I believe just had to do with the reception pattern of the signal - in other words, not really a "pilot" difference. You fly over it, you hear the tone.
I think there were the following types:
- Low powered fan
- High powered fan
- Z
- Dogbone
The first two are fairly obvious what the difference is, but the others I believe just had to do with the reception pattern of the signal - in other words, not really a "pilot" difference. You fly over it, you hear the tone.
RussR
En-Route
If you click on the "Navigation Use" tab, you will see that none of the boxes are checked. I assume this means it isn't actually used on anything. And indeed, I don't see it on any enroute charts OR approach charts. So I question whether it's actually there any more, and perhaps the database just hasn't been updated.
In the past, it may have been used for an airway, or maybe on the ILS for POU runway 6. A fan marker, like an outer marker today, does not provide any lateral guidance, it just identifies when you cross it.
Why the interest in fan markers?
I happened to notice that search option when messing around with eNASR. The mainstream sources gave very little info other than it's not really used any more. I also thought it very strange that the FAA would keep a database of them even though they're not charted or used or even useful.
RussR
En-Route
The outer, middle and inner marker was used on precision approach's, and the outer on some non precision approach's. On an ILS The outer was normally at the FAF. The middle was the normal category one approach DA. And the inner was the cat 2 DA. It was real handy back when we hand flew cat 2 approach's.
From the best of my memory that's what I remember. It also came in handy to put it on the speaker and as soon as the yellow light flashed and the alarm in the speaker. When your passengers asked what was that, and you tell them low fuel alert.
From the best of my memory that's what I remember. It also came in handy to put it on the speaker and as soon as the yellow light flashed and the alarm in the speaker. When your passengers asked what was that, and you tell them low fuel alert.
My instructor taught me to use AN navigation, which makes me really old. Allow for minor brain fade here.
Old AN ranges created airways, and it was important to change from the outgoing range to the incoming range at the proper place, which normally occurred on an estimated time basis. If the change was critical for obstruction clearance or other reasons, a cheap fan marker was placed at the changeover point. The light lit, the tone sounded in your earphones, and you dialed the new frequency and turned. With a lot of skill, or even more luck, you were near the center of the new range.
Not remembered as well, I think the markers on approach procedures were 50 watt, outer markers with a circular dotted depiction were 100 watts, and could be used with ADF radios from 25 to 50 miles out. {The Z markers EDITED after reading Captain Dick Miller's explanation... "Were at the center of the cone of silence at the range transmitter".} Back to my thoughts, dog bones might have been the changeover from outbound of one Adcock transmitter, to the inbound of the next. They would have been more powerful, and had more sophisticated antennae, as the aircraft using them might easily be many miles off course on a windy night.
At the College Park aviation museum, when I was donating some WW 2 items, the lady asked if I would look at an aviation chart that had been donated by the grandchildren of a WW 2 military pilot. It was an IFR chart for the mid Atlantic REGION!, and was marked SECRET. It depicted the AN airway system, marker beacons, and the AN based approaches, including the frequencies. That is where I noticed fan markers at turns in airways. It provided IFR navigation for a region that covered from New York city to South Carolina, Norfolk to Cincinnati. I think that only airports with instrument approaches were depicted, but that was 2 decades ago, and since it was marked secret...................
In the AN airway days, an ADF receiver cost many times as much as an AN receiver plus marker receiver, and was much harder to use accurately than AN. Amelia Earhart found that out the hard way, her navigator was not sufficiently skilled.
As others have said, some of the ones still depicted may have been de commissioned, but the paperwork was not done.
My instructor had promised to fly with me to Norfolk, and perform the AN approach there, as it was the only one still commissioned in the USA, but it was decommissioned before we scheduled it. The club had annual check rides, and this was proposed for the next annual ride. It had fan markers for the step down altitudes.
Old AN ranges created airways, and it was important to change from the outgoing range to the incoming range at the proper place, which normally occurred on an estimated time basis. If the change was critical for obstruction clearance or other reasons, a cheap fan marker was placed at the changeover point. The light lit, the tone sounded in your earphones, and you dialed the new frequency and turned. With a lot of skill, or even more luck, you were near the center of the new range.
Not remembered as well, I think the markers on approach procedures were 50 watt, outer markers with a circular dotted depiction were 100 watts, and could be used with ADF radios from 25 to 50 miles out. {The Z markers EDITED after reading Captain Dick Miller's explanation... "Were at the center of the cone of silence at the range transmitter".} Back to my thoughts, dog bones might have been the changeover from outbound of one Adcock transmitter, to the inbound of the next. They would have been more powerful, and had more sophisticated antennae, as the aircraft using them might easily be many miles off course on a windy night.
At the College Park aviation museum, when I was donating some WW 2 items, the lady asked if I would look at an aviation chart that had been donated by the grandchildren of a WW 2 military pilot. It was an IFR chart for the mid Atlantic REGION!, and was marked SECRET. It depicted the AN airway system, marker beacons, and the AN based approaches, including the frequencies. That is where I noticed fan markers at turns in airways. It provided IFR navigation for a region that covered from New York city to South Carolina, Norfolk to Cincinnati. I think that only airports with instrument approaches were depicted, but that was 2 decades ago, and since it was marked secret...................
In the AN airway days, an ADF receiver cost many times as much as an AN receiver plus marker receiver, and was much harder to use accurately than AN. Amelia Earhart found that out the hard way, her navigator was not sufficiently skilled.
As others have said, some of the ones still depicted may have been de commissioned, but the paperwork was not done.
My instructor had promised to fly with me to Norfolk, and perform the AN approach there, as it was the only one still commissioned in the USA, but it was decommissioned before we scheduled it. The club had annual check rides, and this was proposed for the next annual ride. It had fan markers for the step down altitudes.
Last edited:
- Joined
- Oct 16, 2019
- Messages
- 6,162
- Location
- Atlanta / Marietta
- Display Name
Display name:
Vintage Snazzy (so my adult children say)
I had to look up what a "Fan Marker" was. Interesting how they could do things back in the day with the tech they had at the time.
The instructor that I trained with for my PPL obtained his Instrument rating when the Adcock ranges were still common, and he had to fly a beam across a crows foot station, and also fly an Adcock approach. Captain Miller refreshed the memory of that feature of some ranges.
Back in the day, there was a secret club, known as the "Blind Robins". Repairs on our C150 had been completed, and I was there to fly it home. The whole hanger had been emptied out, scrubbed down, and folding tables set up. There were about a dozen older men chatting. The work bench had a large supply of beer and food. I had gone in to recover our logbooks, and was invited to leave, and the door closed behind me.
I asked around, and found that it was a meeting of the Blind Robins. That was in 1969. All the members must be dead now.
Most likely, from what I could find out, they were pilots who had survived flight in Instrument conditions, and survived, pre gyro. Since rumor was that they were in violation of many FAA regs, they could only share stories with "Members of the club". The host, Turf Field Miller had been a commercial pilot in the '30s, and owned the repair hanger and business at Annapolis, KANP, and at that time, I estimated he was over 65.
Instrument flight was not for the faint of heart in the 1920's and 30's.
Back in the day, there was a secret club, known as the "Blind Robins". Repairs on our C150 had been completed, and I was there to fly it home. The whole hanger had been emptied out, scrubbed down, and folding tables set up. There were about a dozen older men chatting. The work bench had a large supply of beer and food. I had gone in to recover our logbooks, and was invited to leave, and the door closed behind me.
I asked around, and found that it was a meeting of the Blind Robins. That was in 1969. All the members must be dead now.
Most likely, from what I could find out, they were pilots who had survived flight in Instrument conditions, and survived, pre gyro. Since rumor was that they were in violation of many FAA regs, they could only share stories with "Members of the club". The host, Turf Field Miller had been a commercial pilot in the '30s, and owned the repair hanger and business at Annapolis, KANP, and at that time, I estimated he was over 65.
Instrument flight was not for the faint of heart in the 1920's and 30's.