DME Required?

tehmightypirate

tehmightypirate

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TehMightyPirate
So, I was planning a VFR flight to the airport I soloed from and probably have most of my hours from. Just a quick hop from KBGR to KBHB for a $100 hamburger with my girlfriend. As I'm working on my IFR I figured I'd shoot the ILS approach as well if the winds are right for it. However, I was studying the approach plate and got quite confused. See below:

http://155.178.201.160/d-tpp/1312/00992IL22.PDF

So, it's the ILS (not ILS/DME) into runway 22 at Bar Harbor. "DME required" in big bold letters. All good so far. But with DME required why would we not use the JESUL fix minimum always?

So let say we're coming in along the BGR feeder route to BECRA IAF, we do the HILPT, then we're inbound on the ILS. Obviously with the ILS minimums everything makes sense. However, lets say the glide slope is out. I could use the JESUL FIX MINIMUMS via the localizer and DME right? But if DME was out then I could not fly the approach because DME was required, right? Are they given in case you get there and DME isn't working but wasn't on a NOTAM?

Finally, do they really want me to fly 30 nm to the Bangor VOR for the missed approach? I mean, granted if you were doing this in LIFR then you'd probably divert to Bangor ASAP if you had to go missed but, still, that's quite a ways. I suspect it's because Bangor has poor radar coverage at Bar Harbor but, still, that seems really far. Why couldn't you just hold back at BECRA and get ready for another approach and/or head back on the 312 radial to BGR?
 
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You can't shoot an approach solo I don't think. You'd need a safety pilot.
 
Sure he can. He only needs a safety pilot if he is using a view limiting device.

Because he isn't IFR rated, he can't accept an IFR clearance, and he can't fly in IMC. But nothing says he can't fly in VMC and shoot the approach with no view limiting device.
 
PPC1052 said:
Sure he can. He only needs a safety pilot if he is using a view limiting device.

Because he isn't IFR rated, he can't accept an IFR clearance, and he can't fly in IMC. But nothing says he can't fly in VMC and shoot the approach with no view limiting device.
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Right, I should have specified that this will be VFR.
 
tehmightypirate said:
Also, just noticed on the RNAV (GPS) approach, why is the LNAV MDA so much lower than the LNAV/VNAV DA?

http://155.178.201.160/d-tpp/1312/00992R22.PDF
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My guess is the LNAV uses the step down fix JESUL to get the lower MDA, once past the obstacles. The LNAV/VNAV is affected by the same obstacles, but step downs are not an option. The LNAV/VNAV specification forces the DA back and up along the final approach course so that the obstacles are in the visual segment and in the event of a missed approach at the DA, accounting for the momentum sink thru before the aircraft starts to climb, the obstacles will not present a problem. The LPV avoids the same obstacle(s) with its narrower and more accurate path. This situation is not that uncommon.
 
tehmightypirate said:
So, I was planning a VFR flight to the airport I soloed from and probably have most of my hours from. Just a quick hop from KBGR to KBHB for a $100 hamburger with my girlfriend. As I'm working on my IFR I figured I'd shoot the ILS approach as well if the winds are right for it. However, I was studying the approach plate and got quite confused. See below:

http://155.178.201.160/d-tpp/1312/00992IL22.PDF

So, it's the ILS (not ILS/DME) into runway 22 at Bar Harbor. "DME required" in big bold letters. All good so far. But with DME required why would we not use the JESUL fix minimum always?

So let say we're coming in along the BGR feeder route to BECRA IAF, we do the HILPT, then we're inbound on the ILS. Obviously with the ILS minimums everything makes sense. However, lets say the glide slope is out. I could use the JESUL FIX MINIMUMS via the localizer and DME right? But if DME was out then I could not fly the approach because DME was required, right? Are they given in case you get there and DME isn't working but wasn't on a NOTAM?
Click to expand...

The "DME REQUIRED" note is an error. DME is needed only to define JESUL and that's only needed for lower mimimums on the localizer approach.

Finally, do they really want me to fly 30 nm to the Bangor VOR for the missed approach? I mean, granted if you were doing this in LIFR then you'd probably divert to Bangor ASAP if you had to go missed but, still, that's quite a ways. I suspect it's because Bangor has poor radar coverage at Bar Harbor but, still, that seems really far. Why couldn't you just hold back at BECRA and get ready for another approach and/or head back on the 312 radial to BGR?
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How would you get there? A course reversal on the back course then track it back to BECRA? That would probably work, but I don't recall ever seeing a MAP like that, probably because it violates TERPS rules. As it is, there is no positive course guidance back to BECRA without going to BGR first.

An earlier version of this approach had the note "ADF REQUIRED". There were two feeder routes, from Belfast and Old Town NDBs to SURRY LOM, and the MAP went back to SURRY. It appears SURRY is gone; it's not shown in the A/FD or on charts, except for the approach plate where it's depicted as a phantom.
 
roncachamp said:
The "DME REQUIRED" note is an error. DME is needed only to define JESUL and that's only needed for lower mimimums on the localizer approach.
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Awesome, this makes a lot of sense if I ignore the DME required note. Can anyone confirm this? Should this be reported to the FAA/AeroNAV in some way?

roncachamp said:
How would you get there? A course reversal on the back course then track it back to BECRA? That would probably work, but I don't recall ever seeing a MAP like that, probably because it violates TERPS rules. As it is, there is no positive course guidance back to BECRA without going to BGR first.

An earlier version of this approach had the note "ADF REQUIRED". There were two feeder routes, from Belfast and Old Town NDBs to SURRY LOM, and the MAP went back to SURRY. It appears SURRY is gone; it's not shown in the A/FD or on charts, except for the approach plate where it's depicted as a phantom.
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Hmmm, yeah, I remember the old SURRY NDB/LOM. I wonder if they could do some sort of ILS/GPS approach where, if so equipped, you could fly back to BECRA via OBS mode in a GPS? I've never heard of anything like this though, so I doubt it's a valid method with TERPS.

I suspect then that the approach planners figured that once you're established back to Bangor and are under radar coverage again (about 2000 ft and above around KBHB if I remember) then they probably figured that you would turn around and get vectored back to the IAF.
 
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Ahah! I was digging around here https://www.faa.gov/air_traffic/fli...092326738701001-BHB-NDBR&type=ndbr&nasrId=BHB trying to see if the FAA had any revisions planned for the approach (none that I see). In doing this I stumbled upon the "alternate missed approach" listed here: http://aeronav.faa.gov/acifp/ndbr/2011092326738701001-BHB-NDBR/ME_BAR HARBOR_IL22_BHB.pdf

Alternate MA: Climb to 900 then climbing right turn to 3000 on a heading 071.51 and hold on I-BHB NE course to BECRA INT/I-BHB 13.47 DME and hold.
 
roncachamp said:
How would you get there? A course reversal on the back course then track it back to BECRA? That would probably work, but I don't recall ever seeing a MAP like that, probably because it violates TERPS rules. As it is, there is no positive course guidance back to BECRA without going to BGR first.
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I flew this approach in training last weekend, seems to have the kind of missed procedure we're speculating about as well:

http://155.178.201.160/d-tpp/1312/05251IL32.PDF (for whenever the link dies, OKV ILS-32)
 
tehmightypirate said:
But with DME required why would we not use the JESUL fix minimum always?
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Perhaps the DME fails after you pass the FAF? So don't forget to hack the clock at CDLAC (now how the heck do you pronounce....oh, "Cadillac" :rolleyes2:)

So let say we're coming in along the BGR feeder route to BECRA IAF, we do the HILPT, then we're inbound on the ILS. Obviously with the ILS minimums everything makes sense. However, lets say the glide slope is out. I could use the JESUL FIX MINIMUMS via the localizer and DME right? But if DME was out then I could not fly the approach because DME was required, right?
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Right.

Are they given in case you get there and DME isn't working but wasn't on a NOTAM?
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No, as I said, it's in case you lose DME inside the FAF but before reaching JESUL.

Finally, do they really want me to fly 30 nm to the Bangor VOR for the missed approach?
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Probably not, but there are no doubt TERPS reasons they put it there. I'm guessing that if you did go missed, and weren't lost comm, they'd have some other instructions for you pretty quickly.

Why couldn't you just hold back at BECRA and get ready for another approach and/or head back on the 312 radial to BGR?
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At the risk of sounding like your mother, "Because they said so". :D As I said, there are no doubt operational or TERPS reasons why they did it that way, and you'll almost certainly have some other clearance in pretty short order as soon as you're talking to Bangor Approach on the missed.
 
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John Collins said:
My guess is the LNAV uses the step down fix JESUL to get the lower MDA, once past the obstacles. The LNAV/VNAV is affected by the same obstacles, but step downs are not an option. The LNAV/VNAV specification forces the DA back and up along the final approach course so that the obstacles are in the visual segment and in the event of a missed approach at the DA, accounting for the momentum sink thru before the aircraft starts to climb, the obstacles will not present a problem. The LPV avoids the same obstacle(s) with its narrower and more accurate path. This situation is not that uncommon.
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This is ILS/LOC, not RNAV(GPS).
 
roncachamp said:
The "DME REQUIRED" note is an error. DME is needed only to define JESUL and that's only needed for lower mimimums on the localizer approach.
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That's an assumption, not a statement of fact. For a definitive answer, you can ask AeroNav about this by sending an email to 9-AMC-Aerochart@faa.gov -- they respond very quickly to possible chart errors. Please share their response with us.
 
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tehmightypirate said:
Ahah! I was digging around here https://www.faa.gov/air_traffic/fli...092326738701001-BHB-NDBR&type=ndbr&nasrId=BHB trying to see if the FAA had any revisions planned for the approach (none that I see). In doing this I stumbled upon the "alternate missed approach" listed here: http://aeronav.faa.gov/acifp/ndbr/2011092326738701001-BHB-NDBR/ME_BAR HARBOR_IL22_BHB.pdf

Alternate MA: Climb to 900 then climbing right turn to 3000 on a heading 071.51 and hold on I-BHB NE course to BECRA INT/I-BHB 13.47 DME and hold.
Click to expand...

Normally, when an alternate missed approach exists, just the alternate missed approach hold is depicted on the plate and the missed instructions are left to ATC to issue. In this case you'd never know an alternate missed procedure exists by examining the plate because it goes to the existing HILPT.

Makes me wonder why the standard and alternate are not the other way round.
 
mcmanigle said:
I flew this approach in training last weekend, seems to have the kind of missed procedure we're speculating about as well:

http://155.178.201.160/d-tpp/1312/05251IL32.PDF (for whenever the link dies, OKV ILS-32)
Click to expand...

I expect we'll see more of these as NDBs and LOMs are decommissioned. The missed approach here used to go to COGAN NDB, which was 4.4 miles from the threshold.
 
Ron Levy said:
Perhaps the DME fails after you pass the FAF? So don't forget to hack the clock at CDLAC (now how the heck do you pronounce....oh, "Cadillac" :rolleyes2:)
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Okay, that makes sense. You can't find JESUL unless you have DME because you're probably too low for the VOR to be received.


Ron Levy said:
Probably not, but there are no doubt TERPS reasons they put it there. I'm guessing that if you did go missed, and weren't lost comm, they'd have some other instructions for you pretty quickly.
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Makes sense.

Ron Levy said:
At the risk of sounding like your mother, "Because they said so". :D As I said, there are no doubt operational or TERPS reasons why they did it that way, and you'll almost certainly have some other clearance in pretty short order as soon as you're talking to Bangor Approach on the missed.
Click to expand...

Yeah, being an engineer I know that a lot of my clients probably tell other people that behind my back.

"Do we really need to use exactly 10 ASTM A350 bolts, we could totally use A490 bolts and use less of them?"
"Because the engineer said so."

Ron Levy said:
This is ILS/LOC, not RNAV(GPS).
Click to expand...

I asked a second question about the RNAV (GPS) approach into 22 at KBHB as well. His explanation made perfect sense and I do recall reading about this happening elsewhere.

Ron Levy said:
That's an assumption, not a statement of fact. For a definitive answer, you can ask AeroNav about this by sending an email to 9-AMC-Aerochart@faa.gov -- they respond very quickly to possible chart errors. Please share their response with us.
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Wilco.

roncachamp said:
Normally, when an alternate missed approach exists, just the alternate missed approach hold is depicted on the plate and the missed instructions are left to ATC to issue. In this case you'd never know an alternate missed procedure exists by examining the plate because it goes to the existing HILPT.

Makes me wonder why the standard and alternate are not the other way round.
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Fascinating, I had never even knew about "alternate missed approach" until now.

I imagine that, as someone said above, the reason for the primary missed approach is lost comms. If you lost comms and couldn't find your way back to the I-BHB backcourse then you could easily stray pretty much anywhere (though if you were clever you could find your way back to the feeder route and fly back into the IAF).

roncachamp said:
I expect we'll see more of these as NDBs and LOMs are decommissioned. The missed approach here used to go to COGAN NDB, which was 4.4 miles from the threshold.
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Yeah, I wonder what they're intent is to replace the NDBs with? GPS I assume but the approaches that lose the NDB seem to often have nothing to make up their service except a VOR.
 
I agree that there is no reason for the DME being required and it is a mistake. Identifying JESUL is the only reason it would be required and JESUL is optional. Without being able to identify JESUL, the higher Localizer MDA applies. If DME were required for the MAP identification, the timing table would not be on the chart, as it clearly is. Until the approach chart is updated or a NOTAM is issued to remove the DME required note, it is required, but only because the note says so.

I requested a change.
 
Ron Levy said:
Can you show us the AeroNav email saying that? I'd like to see their explanation. Or is this just your personal guess based on your reading of TERPS?
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It's not a guess at all, it's logic. The note is an error because it is not correct; this approach does not require DME.
 
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tehmightypirate said:
I imagine that, as someone said above, the reason for the primary missed approach is lost comms. If you lost comms and couldn't find your way back to the I-BHB backcourse then you could easily stray pretty much anywhere (though if you were clever you could find your way back to the feeder route and fly back into the IAF).
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I don't see how lost comms makes a difference as both procedures are pilot-nav.
 
Hooray, we found a charting error! What fun.

I'm glad I'm not crazy and this really was confusing.
 
Ron Levy said:
That's an assumption, not a statement of fact. For a definitive answer, you can ask AeroNav about this by sending an email to 9-AMC-Aerochart@faa.gov -- they respond very quickly to possible chart errors. Please share their response with us.
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The generally respond with the reason, then want you to call them if you have questions. I've reported a couple issues on saw on a approach change. Never got any real satisfaction or rational answer... or at least one I could understand.

One approach had the DME removed and the mins raised... but nothing had changed on the approach in the last cycle. Looking at the towers referenced for the change, it actually appeared that the approach had been improper for about 12 years (which was how long ago the referenced tower was built). Another issue was they missed a tower about a 1500 feet to the left and about 200 feet below the approach (not depicted on the chart). I tried twice to get them to print that one and gave up. Now I just accept saying "holy ****" every-time I broke out of the clouds on that one. :hairraise: Most of the pilots in the know flying that approach go a little to the right.... its a VOR-A.
 
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Well, that's comforting. I wonder why they would ignore the tower because that's clearly something that most pilots would want to know about. Maybe you should run into it a little bit and then they'll listen. :p
 
It's surprising how close you can legally be on an approach to obstacles.

This is why it is very important to follow the approach.
 
tehmightypirate said:
Well, that's comforting. I wonder why they would ignore the tower because that's clearly something that most pilots would want to know about. Maybe you should run into it a little bit and then they'll listen. :p
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It's not something you'd hit... but on the published approach chart they have lower towers that are farther away depicted.... the closest one being on the RIGHT side (this one on the left). The first time you pop out you really wonder WTF is going on as it does catch your peripheral vision on a side that supposedly has no towers at all.

I tried twice (verbally on the phone) but just got the same recital back to me. I thought about reducing that particular concern to writing but was worried we'd loose the VOR-A approach so didn't bother. On the separate deletion of the DME approach (which I had reduced to writing) it already was being copied to FAA legal so I figured I'd better stop kicking the bear.

Ted DuPuis said:
It's surprising how close you can legally be on an approach to obstacles.

This is why it is very important to follow the approach.
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Agree. If it was on the published chart it wouldn't have surprised me at all. I was just suggesting they might add it.... they didn't.
 
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Ron Levy said:
Like 75 feet vertically on an ILS at 200 DH. Now do you understand why they say max 75 feet error when checking your altimeter? :eek:
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I don't think that statement will hold up to scrutiny.

dtuuri
 
I received a reply from Aeronav:

The DME note and the JESUL Fix minimums [are] correct. You can still use the procedure without DME if you are radar vectored by ATC to the final approach course because the planview (DME Required) note refers to the equipment required for procedure entry. You would require DME if you started the procedure from BGR VORTAC.

Since the procedure name is ILS or LOC RWY 22, DME is not required for the final approach segment. As such you do not have to have DME to complete the final segment and the straight-in MDA would be 680. However with JUZEL Fix minimums using DME, then DME required for straight-in 580 MDA.

Now for the missed approach. Flight Check (FAA pilot's who certify procedures designed) highly discourages using a localizer back course for a missed approach unless there is no other option. Because of this the BGR VORTAC used as the primary missed approach clearance limit even though it's 32.17NM NW of the airport. Beside BGR VORTAC there is not another VOR, VOR/DME or VORTAC close enough to use. If there was it's possible that NAVAID would be used as the primary or alternate missed approach clearance limit, not the back course.
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tehmightypirate said:
I received a reply from Aeronav:

The DME note and the JESUL Fix minimums [are] correct. You can still use the procedure without DME if you are radar vectored by ATC to the final approach course because the planview (DME Required) note refers to the equipment required for procedure entry. You would require DME if you started the procedure from BGR VORTAC.

Since the procedure name is ILS or LOC RWY 22, DME is not required for the final approach segment. As such you do not have to have DME to complete the final segment and the straight-in MDA would be 680. However with JUZEL Fix minimums using DME, then DME required for straight-in 580 MDA.

Now for the missed approach. Flight Check (FAA pilot's who certify procedures designed) highly discourages using a localizer back course for a missed approach unless there is no other option. Because of this the BGR VORTAC used as the primary missed approach clearance limit even though it's 32.17NM NW of the airport. Beside BGR VORTAC there is not another VOR, VOR/DME or VORTAC close enough to use. If there was it's possible that NAVAID would be used as the primary or alternate missed approach clearance limit, not the back course.
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Then the note should be DME or RADAR REQUIRED.
 
tehmightypirate said:
Yeah, I wonder what they're intent is to replace the NDBs with? GPS I assume but the approaches that lose the NDB seem to often have nothing to make up their service except a VOR.
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Yup. GPS.

Soon some of the VORs won't be there outside of dense airspace. It's all been announced.

It's not a matter of if, more a matter of when. FAA doesn't see a need to spend big bucks maintaining ground- based navaids over the long-long-term.

Whether that's shortsighted is debatable. One good solar flare and everyone IMC will be landing at an airline hub that still has a VOR feeder to their approaches. ;)

It'll take a while to get to their new GPS/ADS-B utopia. But it has started.
 
You would require DME if you started the procedure from BGR VORTAC.
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I'm confused... Why is DME required for that? Can't you fly BGR 132 outbound until intercepting the localizer?
 
roncachamp said:
Then the note should be DME or RADAR REQUIRED.
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That's one way to fix it. We had similar cock-ups on some approaches around here. They eventually got fixed. They went the "or RADAR" route because they sit under the DEN Bravo and they want to know where you are or make sure you do. ;)

The person replying from FAA is correct on saying the DME is required for one option in the approach. They're missing that there's another option.

Technically the RADAR requirement is for knowing where folks are on the approach.

They could also remove the requirement altogether to fix the plate. Or publish two separate plates.
 
mcmanigle said:
I'm confused... Why is DME required for that? Can't you fly BGR 132 outbound until intercepting the localizer?
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The issue is false localizers. This problem surfaced about twelve years ago in Canada. There's a possibility of false localizers outside of the localizer Service Volume. It caused a change in policy in the US, you can no longer have a situation where a feeder route that begins outside the normal localizer coverage area is terminated by just the localizer. That intersection requires a fix other than a marker beacon. In this case a DME fix was established.
 
roncachamp said:
The issue is false localizers. This problem surfaced about twelve years ago in Canada. There's a possibility of false localizers outside of the localizer Service Volume. It caused a change in policy in the US, you can no longer have a situation where a feeder route that begins outside the normal localizer coverage area is terminated by just the localizer. That intersection requires a fix other than a marker beacon. In this case a DME fix was established.
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Ahh. Got it. Good old RF doesn't always go only where you want it to go. ;)
 
I think the reason they don't put RADAR REQUIRED is Bangor has limited radar coverage to Bar Harbor due to mild terrain between the airports. They can't see anyone below about 2,500 MSL, so on a bad day they might not be able to see someone at 3,000 MSL and confirm they were on the localizer.
 
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