Marker beacons

[PRB]

From reading the AIM (chapter 1), and Googling the Inter Webs, I'm told that marker beacons are part of the ILS. In real planes, if you're landing on a runway with ILS and marker beacons, but don't have your nav radio tuned to the ILS frequency, do you still get marker beacon lights and tone? In FS we do. Is this accurate?

[bstolle]

Yes, that's correct.

[falcon409]

From reading the AIM (chapter 1), and Googling the Inter Webs, I'm told that marker beacons are part of the ILS. In real planes, if you're landing on a runway with ILS and marker beacons, but don't have your nav radio tuned to the ILS frequency, do you still get marker beacon lights and tone? In FS we do. Is this accurate?
My guess is that you would still get the tones and lights as the marker beacons are also an audible indication to the pilot of his position on final approach and I believe are independent of the ILS approach system in that sense. (strictly a guess though).

Additional info: During the 1960's the marker beacon became an integral part of the ILS system, but prior to that it was as I described above. Also, marker beacons are slowly being phased out in Lieu of GPS coordinates (who knows when that will actually be completed though). Also, since all marker beacons operate on a Freq of 75mhz, even if you weren't tuned to the ILS Freq wouldn't you still pick up that tone? Seems like your radios would have to be turned off completely before you'd not hear it.

[n4gix]

Aircraft that're so equipped have a dedicated receiver for the marker beacon signals.

[PRB]

That makes sense. Since the marker beacons transmit on a different frequency than the ILS, it would have to be a separate system, which you could have installed with or without a "NAV1" radio.

Thanks all.

[fliger747]

Usually there is an audio control for the marker beacons. On the 747-400 and-8 we do not usually turn the audio up, there is a flashing light on the EADI (glass horizon etc display). Our minimums are set via barometric height for Cat I approaches and usually RA for Cat II. For cat IIIB we have an alert height of 100 ft and continue if the aircraft is doing everything correctly, down to 300 RVR.

T

[TeaSea]

The other day I was coming into Brunswick GA and flew over the beacon with my audio on....it started sounding off and I thought my wife was going to jump through the roof.

I told her it was the ejection seat warning.








I'm not a very smart husband......

[expat]

In many years of flying in FS, many if not most a/c have the marker lights on the panel however I do not recall ever seeing them light up on approach or sound a tone, whether I am attempting an ILS approach or otherwise. Is there a different radio/frequency that activates these?

[stansdds]

The other day I was coming into Brunswick GA and flew over the beacon with my audio on....it started sounding off and I thought my wife was going to jump through the roof.

I told her it was the ejection seat warning.

I'm not a very smart husband......:icon_lol::icon_lol::icon_lol::icon_l ol:

[PRB]

In many years of flying in FS, many if not most a/c have the marker lights on the panel however I do not recall ever seeing them light up on approach or sound a tone, whether I am attempting an ILS approach or otherwise. Is there a different radio/frequency that activates these?

The MILVIZ Cessna 310 has a "MKR" button on the audio control panel which, when activated, will play the tones when you fly over the marker beacons. It's pretty loud too! I haven't found another plane that "sounds off" that way yet. I do see the lights often though...

[bstolle]

The MILVIZ Cessna 310 has a "MKR" button on the audio control panel which, when activated, will play the tones when you fly over the marker beacons. It's pretty loud too! I haven't found another plane that "sounds off" that way yet. I do see the lights often though...

Same goes for the default 172.....light & sound

[expat]

Same goes for the default 172.....light & sound

OK, so which navaid (presumably not the same as the ILS frequency for a particular airport) and freq do you tune and which radio do you use?

[bstolle]

OK, so which navaid (presumably not the same as the ILS frequency for a particular airport) and freq do you tune and which radio do you use?

None! As soon as you pass overhead the beacon you get the OM (---), MM (.-.-.-), IM (...) light and aural ID. (if you turned the MKR receiver on the panel on)

http://en.wikipedia.org/wiki/Marker_beacon

[Tako_Kichi]

Most airports in FS are not equipped with marker beacons (just like in real life) so the lights will only be active if the beacons are located on the approach to the airport. These are usually the ones with an ILS system but even then not all ILS equipped airports have marker beacons. Remember too that the beacons are very short range transmitters and the radio beam is directed vertically so you will only pick up the signal for a few seconds (depending on aircraft speed) on the approach, while directly overhead and when flying away from the beacon.

To be absolutely sure the airport in question has them you need to go to 'map view' and zoom in and you should see the symbol for the beacons aligned with the ILS arrow (you also need to make sure the markers are displayed by clicking on the appropriate icon in map view). I discovered, during research for my current development project, that FS is very much like real life in that usually only the outer and middle markers are actually present. The inner marker has been abandoned over the years due to increasing aircraft landing speeds. The increased speed means that the inner marker is now virtually useless as you are committed to the landing (i.e. you have passed the decision point) before you even get to the inner marker as they used to be positioned just outside the 'fence' on short final.

In the real world marker beacons are slowly being phased out as the trend towards GPS/ILS approaches makes them unnecessary equipment.

[bstolle]

In the real world marker beacons are slowly being phased out as the trend towards GPS/ILS approaches makes them unnecessary equipment.

Not quite correct. If there's e.g. no OM you definitely need a substitute (e.g. DME distance) to crosscheck distance vs altitude during the ILS approach.

[PRB]

Finally found an airport that has all three beacons. There aren't many! This is KGEG, Spokane, which has all three on runway 21. Good for testing your marker beacon receiver... Looks like the outer marker is quite a ways out from the other two as well, which is interesting.

[Dain Arns]

Wonder if it has anything to do with Fairchild AFB being to the west, or Felts, which is a GA airport to the NE. :kilroy:
Both are within a few miles of Spokane International if I remember.
(EDIT: i.e. Longer line from outer to middle markers means less chance to "wander".)

[scott967b]

Typical is that a marker beacon receiver is integrated into an audio panel, though stand-alone units exist. All you need in addition is a marker beacon antenna on bottom of AC and some coax to connect. All beacons xmit on 75 MHz so no need to tune. The signal is pretty directional and receiver sensitivity is set you you have to be pretty much on top of it to activate the sound/lights. The 75 MHz is modulated at different frequency to activate the outer/middle/inner options.

The OM is at the FAF, MM at the CAT I ILS decision alt (200) and IM at CAT II decision alt (100). OM often incorporates a co-sited NDB (FAA calls this "locator").

scott s.
.

[TeaSea]

Tako Kichi, I have to disagree with you on the marker beacons. While GPS is now allowing additional approaches and lower decision heights (particularly WAAS equipped), the expense factor for GA aircraft is significant. I'm sure that the FAA would like to eliminate them all, but they would ground a good percentage of the GA fleet (and it would be the middle class pilots that take the hit....not the jet setters).

To upgrade to a GNS-430 in my aircraft is in excess of $12,000.00, and this is for basic functionality....no frills. To obtain what is now considered a "light IFR" package in the airplane is half the total cost of the aircraft. An ILS transceiver, is less than $3K. An NDB, a few hundred bucks (and I can listen to AM radio with it--which would be neat in FSX).

The reality is that while NDB's are indeed being phased out in the Eastern Seaboard of the U.S., the ILS, VOR and the beacons are likely not to go anywhere for some time.

And to get back on topic, scott967b is correct in his description of the functionality. The whole idea is to provide you a visual and audio warning so that you know EXACTLY where you are....so you have to fly EXACTLY over the beacon to get the indicators.