In looking at the approach plates for the ILS 10 R and ILS 28 L for KCMH (the same runway), I see that the ILS for each is the same frequency (111.75). I initially assumed that one was just the back course for the same ILS transmitter. But as I look more closely, they each have a different identifier and morse code, (28L is I-CMH; 10R is I-AQI), and the shaded portion of the flag is on the right side for each. So, I don't think one is supposed to be the back course. Also, there seems to be glide slope information for each side, and I didn't think that there would be glide slope information on the back course. I must be overlooking something, because this doesn't make sense. Is one of these really the back course? If not, given that the ILS frequency is the same for each direction, how does the receive pick up the correct signal?
ILS Question (KCMH)
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peerlesscowboy
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John C Saubak
They only have one at a time transmitting.
wlawr005
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Without knowing anything specific, I would guess they have two xmitters on the same freq...but only broadcast in the direction of the active runway. You're not gonna have both approaches active at the same time.
Clark1961
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wait until they switch it off while you are on the approach...this can happen with any approach (okay, maybe not so much a GPS approach)...which is why ya gotta listen to the damn NDB all the way in...
They have different identifiers. Occassionally I'd fly into Dulles and they'd warn me that they had the opposite end ILS turned up.
steingar
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I thought you were flying in VFR? Don't be so stressed. Its only Ohio.
BigBadLou
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Lou
Never heard of re-using the same frequency for the same runway ILS from different sides, that is intriguing (and makes good sense in a crowded area). I learn something new every day! I am glad I peaked into this thread. Thank you, gentlemen.
I am flying VFR. But I am also working on my instrument. So I looked at the approach plates out of curiosity.
I am not stressed. Just trying to familiarize myself with an unfamiliar airport.
This is one of the reasons it's always important to IDENTIFY the facility you are using.
poadeleted20
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...which is why you always check the ID. Hanscom Tower nearly hosed us a couple of years back when they swapped runways after a front came through but forgot to throw the big switch. We were getting vectored to the ILS 29 by Boston, but the 530 said "I-BED ILS 11" and showed us south of the localizer when we were actually north. Quick call to Boston, the ILS flags out, then 10 seconds later comes back showing "I-ULJ ILS 29" and north of the localizer. Could have been ugly if we hadn't been paying attention.
jordane93
Touchdown! Greaser!
Yep. My CFII drilled this into my head when I did my IR.
There was a crash near here (SHD) a while back where they theory was that the pilots were following the MOL VOR rather than the I-SHD localizer. Not good in even what passes for mountainous terrain on the east coast.
Kritchlow
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They certainly wouldn't do this while an aircraft was in an ILS approach. If it were an NDB approach, the direction can never be switched, as it is non-directional.
Kritchlow
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I almost did this myself once many years ago. Luckily I caught it before it became an issue.
Gucci Pilot
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Had it happen to me twice where it was set to the opposite runway. It is literally a small toggle switch that they change from one runway to the opposite direction. Turned on final and it showed us on the complete opposite side. We told them and they realized they screwed up(which is weird because we checked the ATIS and the runway was the same that it was an hour prior). Localizer didn't end up resetting in time so we just shot the GPS approach. A lot of airports have the same frequency for both directions of the runway.
Kritchlow
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I have had that happen also.. Usually in good weather while using the localizer as a back up.
That said, I've never had it switched during an approach while in the weather. If it were, depending on your equipment, you could fall into a bad trap. Hopefully an erratic glide slope would be a loud alarm..,
denverpilot
Tied Down
The one I saw in person wasn't small and the panel also contained the monitoring gear and large 2" lights showing what was selected and also what was being received correctly by the monitoring equipment.
Hank S
En-Route
CMH is big, flat and wide open, pretty easy to land there, but I've not shot a full approach (broke out and flew the visual, or went VFR). Lane is good, but watch the ramp fee! (Even just for a quick stop.)
My first visit there was at just over 100 hours, tower turned my downwind 6nm out with the airliners, gave me one to follow (yeah, right!), then asked me to keep my speed up for the MD80 following me. Look for the colored dots, one of those is the airliner you'll be asked to follow if VFR. Had to add throttle after landing to reach the high speed exit at 3000' on 27.
With more experience, CMH isn't bad.
Gucci Pilot
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We had just gotten the first vector, so we had just swapped our avionics from FMS tracking to the ILS. She just kinda did a make-shift ASR in hopes we would pick it up in time. We just said, heck with it, we'll do the GPS. We were still above her MVA and we certainly weren't gonna decent anymore until we had some form of guidance lol.
Different for different towers. The base I fly out of it is a small toggle switch about the same size as a light switch.
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azure
Final Approach
Ramp fee for a bugsmasher? I've landed at CMH twice in my Cardinal, parked at Lane both times. They were courteous and very helpful, even drove me over and picked me up from the Enterprise rental desk in the main terminal. I never paid a ramp fee, though the second time I did buy a small amount of fuel (something like 15 gallons). But I asked about fees and they were quite clear that there were none for any of the services I used.
Oh yes, the second time I did fly the ILS on 28L. This was in September 2013. I think they had just changed the LOC frequency IIRC. Same frequency for the two directions is also the way it's done at FNT. You definitely have to ID the navaid.
bflynn
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I just had an image of someone sitting there flipping the switch back and forth trying to get the lights to come on. That could be interesting...
Gucci Pilot
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Need to get the airport lights rigged up to a Clapper in the tower. That would be awesome.
Pilot: "Tower, can you turn up the approach lights?"
CLAP! CLAP!
Tower: "Done..."
poadeleted20
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Sure looks like HABOP is an IAF (in fact, the only IAF), but they accidently left the "IAF" off. Suggest you send that one in for evaluation/correction. See the inside front cover of the TP book or the Digital Terminal Procedures Supplement for the email address. If there's no IAF at all, I believe it's supposed to say RADAR REQUIRED, and this one only says DME OR RADAR REQUIRED, apparently because the IAF HABOP can only be identified by DME (off either I-CMH LOC DME or APE VORTAC DME) or an ATC radar call.
Pretty much how PCL works now.
Nice thing about additional automation in the cockpit. In addition to the purple line superimposed over the approach plate whose deviation would become apparent, my 480 gets irate at you if you do not have the VOR or ILS as appropriate tuned after you told it that's the approach you wanted to fly. First it just pops up a reminder and puts the appropriate frequency in the standby. Later on it actually switches for you I believe.
azure
Final Approach
I would have to check, but I don't believe it switches on a VOR approach, only on an ILS or LOC. I also believe it's dependent on a setting in the system config, but I don't have the pilot's guide handy to check.
petrolero
Pattern Altitude
agree. Learned something. Thanks.
poadeleted20
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According to the GNS 480 manual, "Automatic switching of CDI output is available for ILS, localizer, SDF and LDA approaches. Automatic CDI switching is not available for backcourse approaches or VOR approaches." And while autoswitch for LOC/ILS/SDF/LDA is preset "on" at the factory, you can turn it off.
However, for all those approaches including VOR and LOC(BC), when the approach is first selected or executed, the frequency is automatically checked to see if it's correct. If the frequency is incorrect, you will receive a message about that asking you if you want to place the ILS frequency in the active frequency field immediately, which you do by pressing the Menu/Enter key when the frequency message is received. If you cancel that message, you'll have to dial it in manually later on. And yes, this is somewhat different from how the GNS430/530, GTN650/750, and G1000 operate.
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SbestCFII
Line Up and Wait
That loos right. The IAP shows localizer transmitter on the West end of the runway for the 28L ILS and on the East end of the runway for the 10R ILS. The both post the same DME channel (54) which appears to be at the West end of the runway from the profile view of Rwy 10R. Never seen that before.
azure
Final Approach
Yep, sounds like I remembered basically correctly. SDF and LDA approaches are rather rare birds, can't be too many of them left anymore.
The important thing, if you're going to rely on automatic CDI switching with the 480, is to remember on which kinds of approaches it switches automatically and on which it doesn't. Or better yet, whether you let it switch automatically or not, VERIFY the d_mn frequency and ID the navaid. B)
poadeleted20
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SDF's, yes, the FAA has been getting rid of them, but LDA's are still around in significant numbers -- Hartford CT and Roanoke VA being two notable ones driven by some nasty terrain issues.
I teach my trainees the Ronald Reagan rule on that -- "Trust, but verify."
flhrci
Final Approach
On a related note,
I was perusing the NOTAMS for KCMH tonight and found this letter to airmen from the CMH tower. It essentially says to do practice approaches, you should file an IFR flight plan. So, that means you can't just take up a safety pilot and do approaches any more in plain jane VFR. You have to have a instrument current pilot onboard that can file if you cannot file yourself. Such as being out of currency. Just a little harder to get your currency back or maintain it now.
I am surprised. They used to be more accommodating. Must be getting busier over time.
https://notams.aim.faa.gov/lta/mai/viewlta?lookupid=679667602175301243
David
I was perusing the NOTAMS for KCMH tonight and found this letter to airmen from the CMH tower. It essentially says to do practice approaches, you should file an IFR flight plan. So, that means you can't just take up a safety pilot and do approaches any more in plain jane VFR. You have to have a instrument current pilot onboard that can file if you cannot file yourself. Such as being out of currency. Just a little harder to get your currency back or maintain it now.
I am surprised. They used to be more accommodating. Must be getting busier over time.
https://notams.aim.faa.gov/lta/mai/viewlta?lookupid=679667602175301243
David
Gucci Pilot
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Yes you can; no you don't
That basically said that when you are doing practice instrument approaches and talking to approach control, they are going to use standard IFR separation(helps avoid confusion with the controllers and it is more conservative). It conveniently listed the approach frequency to contact for all the different airports. It said they would like you to be IFR but it is certainly not a requirement. Also because you are VFR you are mot cleared to execute the published missed so if you are going missed, you have to coordinate that with ATC before going missed.