The O'Hare Outer Marker Beacons Report

Status
Not open for further replies.

chgomonitor

Silent Key
Joined
Jan 27, 2003
Messages
427
Location
Chicago
I took a 75 mile very round trip yesterday and visited all of the outer marker sites, or what is left of them;

(It should be noted that several of these runways are very seldom used for O'Hare landing anymore, especially given the expansion based trend towards east-west operations).

LEAMA 14L - Northwest Community Hospital on Kirchoff in Arlington Heights. Out of service. Replaced by the JEXOS intersection (no marker) overhead. The transmitter shack remains, but not for long. Site being dismantled. One end of the NDB array hanging from the one remaining pole. No 75 MHz array and no transmissions. Salvage dumpsters inside the fence line surround the transmitter shack. About to vanish into the greater hospital grounds.

CHSTR - 14R. Rear of Elizabeth & Meadowbrook condos off of Algonquin northwest of Golf Road. NDB array dismantled and off air. Insulators hanging from the remaining center feed point post. 75 MHz on the air and in good condition. Sign on door reads; "ORD 14R OM". Recently maintained. Current Approach plate for 14R has this marked as an intersection only, no mention of the outer marker beacon.

ZENAH Intersection. 9L (new). Near the IDOT yard southeast of I-290 and Biesterfield Road. No marker at this location, its just an intersection in the sky. I don't think they are landing 9L yet. The current Approach plate for 9L makes reference to the I-SAJ Distance Measuring Equipment antenna.

LANSE 9R (formerly 9L). Right shoulder of the Elgin-O'Hare Expressway east of Rohlwing Road / I53. No NDB at this site, never has been. 75 MHz beacon is on the air here. Outer Marker not shown on current Approach Plates for 9R, LANSE is now shown as an intersection only.

DEANA formerly 9R now 10. Replaced by the BUGSE intersection directly overhead. Rear of the Hawthorn Industrial Park, east of I53 south of Irving. Serta corporation is no longer here, the business is now Darley, Inc. Site is at the rear of their parking lot. Recent truck tire tracks in the snow leading to the gate. This famous NDB which transmitted from an impressive vertical tower on 350 KHz for many decades is off the air. The 75 MHz array is still present but also off the air. DEANA is out of service, quite sad.

LAPPS 4L. West side of Addison Road south of Interstate Road in Addison. No NDB at this site, never has been. Recently maintained, 75 MHz beacon transmitting. Current Approach plate for 4L lists this as both an outer marker and as an intersection.

REKKS 4R. West side of Elmhurst Road / I83 1/2 mile south of North Avenue. No NDB at this site, never has been. In somewhat poor condition, the 75 MHz array is still up and transmitting but leaning over a few degrees. Very weak signal here. REKKS is on the current Approach Plate for 4R marked as both an Outer Marker and an Intersection.

JOCKY 32L. In the woods northwest of Thatcher and Chicago Avenue in River Forest. (Named for the nearby Maywood Park racetrack). The 75 MHz array is up and transmitting. The NDB array is still up in the trees. I've never found a frequency for this NDB as I've never found it transmitting and yesterday was no exception. Current Approach plate for 32L shows both an outer marker and an intersection.

INDDY 32R. Southside of Greenfield just west of Harlem Ave at the north border of the Fenwick High School athletic field. 75 MHz beacon transmitting. Big surprise here, a very jury rigged NDB antenna strung between three 15 foot square metal frames next to the site, very odd. I searched for NDB transmissions but found none. Current Approach plate for 32R lists this only as an outer marker beacon.

WILLT 28 (formerly 27L). Rear of the school yard a block north of Gunnison on Natchez. No NDB has ever been here. Site is totally gone and black topped over for more lot parking spaces. A sad 6 inch wire hangs from the power pole which once fed this site, now gone. Replaced by the WILLT intersection overhead. Current Approach plate for 28 shows the I-TSL distance measuring equipment ("DME") antenna.

TAFFS 27L (formerly 27R). Now the overhead TAFFS intersection only. Rear of Taft High School off of Bryn Mawr west of Nagle. Site is gone. The only trace remains the odd access gate in the modified high school field fence. Current Approach plate for 27L shows the I-IAC DME antenna a couple hundred feet from the start of the runway.

SIBLY 27R. Intersection only. New. Located roughly on Milwaukee north of Albion in or near Niles. No marker at this intersection ground location. With 27R now operational for landings I've observed pilots calling this intersection to the tower for miles in either direction from here, mostly well west of here. Sit on Pratt anywhere east of River Road when they are landing 27R and you'll see what I mean if you are listening to the new North Tower frequency 135.925.

LAIKE. 22L. Rear southeast corner of the storage facility on the east side of Waukegan south of Dempster. I was amazed to find the old Monogram factory erased and replaced by the Trafalgar Woods condo development. A new street on the north end of the condos - Meadow Lane, runs east from Waukegan. Take it east to where it ends and you can now see the 75 MHz antenna array in the back of the storage yard for the first time! Amazing, but the 75 MHz beacon was off the air, not transmitting. There has never been an NDB site at this location. Current Approach plate for 22L lists this both as an outer marker and as an intersection.

RIDGE 22R. East side of the Golf-Milwaukee shopping plaza north of Golf Road east of Milwaukee. Replaced by the RIDGE intersection directly overhead. Site fencing and the pole which supported the 75 MHz plumbers nightmare array remain and little else. There has never been an NDB here. Site is out of service. I had previously detected traces of a 75 MHz signal near here. Having LAIKE off the air sort of confirmed that is what I was hearing, nothing heard yesterday.

So, this little expedition explains why when I tune my shortwave radio below 500 KHz I rarely hear any non-directional beacons ("NDB's") any more - O'Hare's are all off the air. The end of an era. With increasing reliance on advanced ILS and GPS landing techniques I can't say it is much of a shock. NDB has/is become antiquated technology at bigger airports.

I'm a little more surprised by the 75 MHz outer marker beacons slipping into history as well. A few are still marked on Approach plates as "OM", at least for the ones still in use and on the air. But they are clearly becoming fewer and farther between. I know how the intersection deals works, a radial drawn as a line from a VOR beacon (mostly Northbrook or ORD VOR's for O'Hare) or other nav point.

But if a pilot is on the ILS landing O'Hare and they don't get the flag or nav system beep as they pass over the 75 MHz outer marker ground beacon, well, are they using some other technology to call the exact point? Is it the DME data? Does they ILS system itself give them a distance reading or something?

Happy Scanning! - Ted
 

immelmen

Member
Joined
Jun 13, 2007
Messages
377
But if a pilot is on the ILS landing O'Hare and they don't get the flag or nav system beep as they pass over the 75 MHz outer marker ground beacon, well, are they using some other technology to call the exact point? Is it the DME data? Does they ILS system itself give them a distance reading or something?

Happy Scanning! - Ted
DEANA brings back some memories!!

To answer your question about how to identify the FAF....for transport category jets (most ORD traffic) the FMS/INS is the primary method of navigation.(INS=Inertial Navigation System. It is initialized on the ground by loading a known Latitude, such as a gate or GPS position. It then fixes its position by sensing the rotation of the earth. after its aligned, laser ring gyros and accelerometers are used to very accurately sense the aircraft's position in space for the duration of the days flying until electrical power to the plane is turned off. ) It shows all the way points of the flight plan on the ND(Nav Display) as white or magenta stars. When you are given an approach to expect, you load that into the FMS and up pop the way points of that approach on the screen, including the FAF's. The ND with the PFD make up a "Glass Cockpit". Gone are the days of tuning the LOM and the marker beacon volume is only turned up for a CAT II or lower ILS.

For the ancient DC-9's and cargo 747-200's that lack the FMS/"Glass cockpit" package, DME from the ILS is used to Identify the FAF. The ILS itself is the last radio aid to navigation that is routinely used in modern air carrier aircraft.
 
Last edited:

K4DHR

Member
Joined
Jul 13, 2007
Messages
131
Location
Olive Branch, MS
The same thing is occurring at Hartsfield as well. The inner markers are still in place because they're required for the Cat II/III approaches, but both the CATTA and REDAN NDBs have been decommissioned. IAPs still show the OMs in place for the other runways, but they are in lighter type, ie., they are no longer required for the approach. I suspect that they'll probably keep them running until they break, then they too will be removed. The OM at the airport I fly out of has been OTS for quite some time and almost all recent ILS approaches that I have seen installed recently usually co-locates a DME with the localizer instead of a OM/MM.

If a runway lacks a DME (not all ILS systems include a DME) if there is adequate radar coverage, ATC can call the FAF if requested. About the only time that would be necessary is if an airplane was only equipped with one reliable NAV radio, a situation not too likely unless you're flying a C152.

Speaking of NDBs in general, almost every time a new low altitude chart is released I see a few more NDBs being marked as shutdown. Only one of about a dozen or so aircraft at the club I rent from has a properly functioning ADF. Even one of the newer 172SP's ADFs is unreliable (I don't know why it hasn't been tagged, maybe so people can still listen to AM radio while flying?) and I don't think there is any intention of fixing it. Except maybe in Alaska, I give NDBs in the US maybe another decade before they're gone.
 
Last edited:

immelmen

Member
Joined
Jun 13, 2007
Messages
377
The same thing is occurring at Hartsfield as well. The inner markers are still in place because they're required for the Cat II/III approaches, but both the CATTA and REDAN NDBs have been decommissioned. IAPs still show the OMs in place for the other runways, but they are in lighter type, ie., they are no longer required for the approach.
FWIW, any air carrier aircraft built since the early 80's does not use any radio navigation save the ILS(they are equipped with it, its just not used). Its been years since radio nav was the backbone of the fleets navigation capability. with the retirement of the 737-200's, 727s, and classic 747's even the VOR is no longer used in the airline world (the last exception is NWA DC-9s) Now, its play connect the dots on the screen via RNAV (INS). Navigation procedures are no different now then they were in 1989(on the average airbus/737/75/6), the disappearance of ground base navaids is un-noticed in the cockpit.
 

poltergeisty

Truth is a force of nature
Banned
Joined
May 7, 2004
Messages
4,020
Location
RLG, Fly heading 053, intercept 315 DVV
Ah, why do they always take the fun out of things? :lol:

So this means non-carrier aircraft must have a GPS then? Or at least in about ten years. The radio stack is there, but VOR's are going the way of the Dodo bird as well, then the only thing to use is GPS until established.

...Hope the birds way up there stay a float.
 

chgomonitor

Silent Key
Joined
Jan 27, 2003
Messages
427
Location
Chicago
Thanks

Thanks for the many informative and illuminating replies.

I'll tell you one thing as it pertains to visually spotting and identifying aircraft while sitting out under a FAF and monitoring the associated tower. Without the beep from passing over a 75 MHz outer marker and the positive human interaction that provides these guys now have miles of variation with regards to when they actually get on the air and call in that they have reached reached the point.

I used to sit under RIDGE for hours at a time watching them going into O'Hare. It was like clockwork, every single plane would call in an ID directly overhead. When things got busy on the air they sometimes weren't able to squeeze in the call and might be a half mile inside the point, but that was it.

Now I sit under these intersections and almost nobody calls right at the point. Almost everybody calls well inside, often by many miles. I was sitting near the start of the landing runway and saw one guy call SIBLY about a half mile from landing.

Makes visually ID'ing these guys a lot harder.

Thanks again! - Ted
 

immelmen

Member
Joined
Jun 13, 2007
Messages
377
Without the beep from passing over a 75 MHz outer marker and the positive human interaction that provides these guys now have miles of variation with regards to when they actually get on the air and call in that they have reached reached the point..........

.....Now I sit under these intersections and almost nobody calls right at the point. Almost everybody calls well inside, often by many miles.
Ted, I think the variations you see in reporting the FAF are due to other variables. Some food for thought...The methods used for identifying the FAF have not changed in over 25 years. The marker beacon system remains muted unless a CAT II or III ILS is being flown(its annoying and interrupts what ever checklist or dirty story your in the middle of) . The FMS flight plan driven by the INS/IRU is very accurate and more reliable then the radios.

ORD has a set special way of doing everything, and keeping your mouth shut until the FAF is one of those things. Think of it as waiting till your first in line at the "Soup Nazi" on Seinfeld before you order your soup. Tower controllers at ORD are busy enough, they know your there and they don't need to worry about you till your next in line.

crossing the marker is also the approximate point at which the most significant speed changes take place and when you start setting up the final landing configuration. Shortly after is when the landing checklist is called for and run so there are a few things going on that take time to accomplish. Combine that with over-worked, exhausted and disgruntled crews, compared to 15 years ago, and you can start to see why there is a "margin" in the inbound call especially during visual conditions.

...having said that, when the weather gets low, everybody involved tightens up.
 

rmiller818

Member
Joined
Jun 6, 2003
Messages
506
Location
Marietta GA
FWIW, any air carrier aircraft built since the early 80's does not use any radio navigation save the ILS(they are equipped with it, its just not used). Its been years since radio nav was the backbone of the fleets navigation capability. with the retirement of the 737-200's, 727s, and classic 747's even the VOR is no longer used in the airline world (the last exception is NWA DC-9s) Now, its play connect the dots on the screen via RNAV (INS). Navigation procedures are no different now then they were in 1989(on the average airbus/737/75/6), the disappearance of ground base navaids is un-noticed in the cockpit.
I wouldn't say that, sometimes the INS or FMC or GPS fails, then your left to VORs on the Jet airways. Heard it a few times (ironically all in RJs)

I personally am not sad to see the NDBs go, so unreliable and just a pain in the neck. Plus, with GPS, the FAA doesn't have to maintain thousands of ground based NDBs and VORs, makes things simpler in that respect. I still think it is important to know how to use these however, never know when GPS will quit on you.
 

immelmen

Member
Joined
Jun 13, 2007
Messages
377
I wouldn't say that, sometimes the INS or FMC or GPS fails, then your left to VORs on the Jet airways. Heard it a few times (ironically all in RJs)
well....I would say that(speaking about part 121 airline flying only as the OP referenced Chicago O'Hare). For as long as I have been flying aircraft equipped with INS/FMS, I have never conducted a flight by tuning in and navigating via VOR signals. I have had one of the IRU/FMS's take a dump, but that is why we have two on board and the wide bodies have three...the flight continued normally. The odds that both or all three go T.U. at the same time is virtually zero(unless you have far more serious problems). ... the beauty of redundancy.

It may happen once in a very blue moon but it is exceedingly rare to the point I don't ever recall hearing about it. Regarding the RJ's you were hearing. Keep in mind that with an INS/FMS you still fly the same Jet routs and VOR to VOR as in the old school(with the addition of the direct capability), you just dont tune the VOR and use its signal to navigate, the INS does it for you internally. Also, the RJ only has one CDU so if it dies inflight then they do lose RNAV capability. Also, the CDI's and RMI's behave identicaly when slaved to the INS vs. radio nav, so it not like you get rusty from lack of use, the radios just don't paint the pretty picture on the ND.
 
Last edited:

poltergeisty

Truth is a force of nature
Banned
Joined
May 7, 2004
Messages
4,020
Location
RLG, Fly heading 053, intercept 315 DVV
One thing that I have wondered about is that if all NDBs were eliminated, then why have a STA (station) button in the EFIS control panel control?
Plus, your transitions are used with NDBs as part of the flight plan. :confused: So will these NDBs become just like stranded NAV aids in the future?
 
Last edited:

immelmen

Member
Joined
Jun 13, 2007
Messages
377
One thing that I have wondered about is that if all NDBs were eliminated, then why have a STA (station) button in the EFIS control panel control?
Plus, your transitions are used with NDBs as part of the flight plan. :confused: So will these NDBs become just like stranded NAV aids in the future?

by station button do you mean the ability to display the locations of NDBs on the glass Nav Display MFD? And when you mention transitions, are you referring to transitions on an approach procedure that may use an NDB as the IAF?

If so the answer to both questions is the same. The jet still needs to know where the various Navaids are, even if they don't physically exist anymore, as (RNAV-only procedures excluded) your still flying a published route/procedure that was based on radio navaids(why create new instrument procedures when the old one still work..). Its just that the manner in which the airplane knows where the fix is and how to navigate to it is done differently then the old school.

Sitting at the departure gate you can enter "J156.DJB" and line select it to the flight plan and every VOR and intersection on Jet 156 between your position and Dryer VOR pops up on the screen. You can load the approach you expect at the destination and it will show you the NDB/LOM even though it is 1500 miles away...no need for the actual NDB station to even exists anymore as the FMS knows where it is supposed to be(for the airlines purposes that is, GA aircraft may still use).

The "station" option simply allows you to display other navaids near you that are not part of your flight plan for reference.
 
Last edited:

poltergeisty

Truth is a force of nature
Banned
Joined
May 7, 2004
Messages
4,020
Location
RLG, Fly heading 053, intercept 315 DVV
Yes, the display of Navaids on the MFD using the STA button. I actually know this because I have several planes for Flight Simulator that have an FMC. :lol: I'm very familiar what you use in real flights. Just curious as to how navigation would be if NDBs are going to become obsolete. What I'm saying here is that I guess the NDBs would become Naviaids. Even though they pretty much are Navaids to the FMC, does the FMC not actually tune to the actual frequency as part of augmentation (Sensors) along with GPS and the INS? Wouldn't matter I guess, but just interesting.

I'm bad at explaining things in writing.
 
Last edited:

immelmen

Member
Joined
Jun 13, 2007
Messages
377
I am a bit confused by the way your using navaid. Navaid is short for Radio Navigation Aid, so an NDB is already a navaid along with VOR's and ILS ect. I think what your getting at is if the airlines still tune radio navaids to assist in navigation. The answer is, except for the ILS, no 99.9% of the time.

Navigation (for commercial airlines) would not change a bit if every physical NDB vanished tomorrow. The FMC does not in any way tune the frequency to use the signal emitting from an NDB or VOR. The station locations are in the FMS database and the FMS is told where in space the jet is by the INS. it then knows that, referencing the aircraft's current position, the NDB should be at a given point/bearing/distance from that current location and puts it on the screen.

The same idea is used for EGPWS (enhanced ground proximity warning system) The radar altimeter only looks straight down, which does you know good if there is a big mountain in front of you (ie. american airlines 757 in Cali, Columbia) Therefore, the FMS has the elevation of earths terrain loaded into its database, and via position input from the INS will display the locations and elevations of the surrounding terrain on the Nav Display screen and activate the "TERRAIN TERRAIN" -- "WHOOP WHOOP PULL UP" when necessary. Its all done internally from a database....
 

rmiller818

Member
Joined
Jun 6, 2003
Messages
506
Location
Marietta GA
Regarding the RJ's you were hearing. Keep in mind that with an INS/FMS you still fly the same Jet routs and VOR to VOR as in the old school(with the addition of the direct capability), you just dont tune the VOR and use its signal to navigate, the INS does it for you internally. Also, the RJ only has one CDU so if it dies inflight then they do lose RNAV capability. Also, the CDI's and RMI's behave identicaly when slaved to the INS vs. radio nav, so it not like you get rusty from lack of use, the radios just don't paint the pretty picture on the ND.

yes, I understand all that, I fly too so you don't have to be so condescending. These were actual flights where they did NOT have RNAV capability due to a failed INS/FMS/FMC whatever was not working for them. As a result they used the jet airways and could not go direct. Makes sense why I have only heard it in RJs, didn't even think about them only having 1.

But overall your correct in saying that it is not used primarily for navigation in air carrier ops, all I was saying is that sometimes they do have to use them as that is their only choice.
 

immelmen

Member
Joined
Jun 13, 2007
Messages
377
yes, I understand all that, I fly too so you don't have to be so condescending. These were actual flights where they did NOT have RNAV capability due to a failed INS/FMS/FMC whatever was not working for them. As a result they used the jet airways and could not go direct. Makes sense why I have only heard it in RJs, didn't even think about them only having 1.

But overall your correct in saying that it is not used primarily for navigation in air carrier ops, all I was saying is that sometimes they do have to use them as that is their only choice.
I did not mean to be, sorry if it seemed that way. Not sure what the MEL book says for the RJ with single CDU's, but on our aircraft with dual FMS, only one can be MEL'd at a time. we cannot dispatch a flight with two FMS's inop/MEL so this would never be an issue. I could have explained that better i suppose. either way, FMS or not, your still on the Jet routs most of the time.
 

sopdan

Member
Joined
Jan 14, 2006
Messages
14
We have one FMS on our Saabs... If it's MEL'd, then we file /A (old fashioned VOR/DME). All of the NWA DC-9s still fly around with just VOR/DME/NDB, there is no type of GPS/INS/IRS system at all.

As far as not needing VORs if you have an FMS, that's not entirely true. Mine (UNS-1) uses a combination of GPS and DME to give the most accurate position. I am able to pull up a page of the sources it is computing from, and there is always a good number of VOR/DME stations listed. (while in the air)

We also have no GPWS, but rather TAWS (the GPS database type). The TAWS system has it's own independent GPS, so there are no worries if the FMS is inop.
 

immelmen

Member
Joined
Jun 13, 2007
Messages
377
clarification

...As far as not needing VORs if you have an FMS, that's not entirely true. Mine (UNS-1) uses a combination of GPS and DME to give the most accurate position. I am able to pull up a page of the sources it is computing from, and there is always a good number of VOR/DME stations listed. (while in the air)...
Sorry, I think I was not very clear as to what I was talking about in my posts. As the original post was concerning Chicago O'Hare, where the majority of traffic is Part 121 Mainline Turbojet aircraft, that is what my posts on the topic were concerning. ie. Boeing, Airbus and McDonald-Douglas equipment (except for the NWA Diesel 9's and cargo 747-200's as I mentioned in earlier )

Universal brand FMS's are not used on these aircraft, but rather found in turboprops such as the 340's, ATR's and Q400's(I was not including them in my comments). The Honeywell boxes on mainline jets are fed from the multiple INS/IRS/IRU's on board. A GPS signal is used to initialize the IRS.

At the risk of confusing the issue, the FMS in mainline aircraft can be set up to automatically tune the nav 1 and 2 radios to the next navaid in the flight plan for use with an RMI, but the FMS DOES NOT sense the signal or use it for navigation.
 

rmiller818

Member
Joined
Jun 6, 2003
Messages
506
Location
Marietta GA
I did not mean to be, sorry if it seemed that way. Not sure what the MEL book says for the RJ with single CDU's, but on our aircraft with dual FMS, only one can be MEL'd at a time. we cannot dispatch a flight with two FMS's inop/MEL so this would never be an issue. I could have explained that better i suppose. either way, FMS or not, your still on the Jet routs most of the time.
Yea, I was a bit surprised that they can dispatch with the FMS inop, but they do. Real pain in the neck from what it sounds like.
 
Status
Not open for further replies.
Top