LPV approaches

[John Collins]

I think when you revert from LPV to LNAV due to losing WAAS, you might need to use a different approach procedure altogether, since the missed approach or other parameters may be different (MAP, step downs?), so it's not just the minimums that may change, and it's not like ILS simply reverting to LOC on GS loss.

You should be able to use the same approach as an LNAV. IOW if the approach has LPV and LNAV, and the downgrade is required, the LNAV procedure on the same approach is followed and the same missed approach procedure is flown if needed. If the LPV does not have an LNAV option on the same chart, then the approach will be charted as Alternate Not Authorized with the black A symbol with the white A followed by NA.

I believe the reason for the 800-2 verses 600-2 has to do with the lateral guidance when there isn't a GS available. In the case of an ILS, it is still the localizer. In the case of the LPV, the localizer performance for lateral guidance is also downgraded to LNAV guidance and integrity, IOW the backup is more like a VOR than a localizer.

In any case, alternate minimums higher than the standard values will be used anytime the LNAV MDA or Localizer MDA is higher. Alternate minimums are based on worst case where the approach may still be flown. With an ILS, the only mandatory capability is that the localizer procedure may still be flown. With the LPV, the only mandatory capability is that the LNAV procedure may be flown.

There are two general kinds of system failures that the LPV will require a downgrade:

1) WAAS is available, but the integrity at the time of the approach does not support the LPV. Because of geometry, usually the vertical will fail before the lateral. For a DH of 200, VPL must be <35 meters and HPL must be <40 meters. The downgrade to LNAV only tests for HPL and it must be <556 meters.

2) WAAS is unavailable. This is extremely rare but happened once since the system was put on line for about a four hour period when a WAAS software update went bad. In this case, the default is to RAIM and standard GPS service applies. The RAIM must also be <556 meters (0.3 NM).

 

[John Collins]

Yes, that's the giveaway that the approach has fallen back to LNAV.

Agree.

A more common misunderstanding has to do with using LP minimums. Many pilots erroneously assume that because their aircraft has a WAAS GPS, they may fly the LP minimums. One must also get the LP annunciation in order to use these minimums. G1000 WAAS systems (with a very few exceptions) and many other GPS WAAS systems that use down level software don't support the LP approach type. These aircraft can't legally fly the LP minimums. They are restricted to flying the LNAV minimums.

 

[azure]

Thank you for the example. My assumption is that in your example, flying the GPS Z LPV and losing WAAS, you can't just quietly revert to the GPS Y LNAV on your own (though you can revert to GPS Z LNAV), since reverting to a different approach such as GPS Y means you'll be flying a different missed approach.
I guess if you lose comms (or are nordo to start with) you could do that, but otherwise you'd need a new approach clearance (or a retroactive one, if there is such a thing) from ATC for the GPS Y.
This used to be so simple when you just lost GS and reverted to LOC all on your own.

I think that's correct, but as you wrote, you still can do that on an LPV approach, as long as you revert to the LNAV procedure on the same approach plate. Isn't that the same thing as you'd do for an ILS or LOC where you lost the GS? Would you or could you ever revert to a LOC-only approach on a different approach plate?

There's a pair of approaches at KDTW, an ILS Y and an ILS Z or LOC, both to 4L. The ILS Y has no LOC-only minimums. If cleared for the ILS Y and you lose the GS, can you revert to flying the localizer for the ILS Z or LOC? The missed approach procedures of the two approaches are identical; but the localizer frequencies are different. My guess is you can't, and most likely wouldn't want to since it would mean tuning and IDing another localizer.

 

[RotorDude]

I think that's correct, but as you wrote, you still can do that on an LPV approach, as long as you revert to the LNAV procedure on the same approach plate. Isn't that the same thing as you'd do for an ILS or LOC where you lost the GS? Would you or could you ever revert to a LOC-only approach on a different approach plate?

There's a pair of approaches at KDTW, an ILS Y and an ILS Z or LOC, both to 4L. The ILS Y has no LOC-only minimums. If cleared for the ILS Y and you lose the GS, can you revert to flying the localizer for the ILS Z or LOC? The missed approach procedures of the two approaches are identical; but the localizer frequencies are different. My guess is you can't, and most likely wouldn't want to since it would mean tuning and IDing another localizer.

I agree. I guess in a nordo situation you can do whatever you want, but obviously switching LOC frequencies on final approach is unwise. Of course with a load of ice or a raging cabin or engine fire, who knows.

 

[RotorDude]

You should be able to use the same approach as an LNAV. IOW if the approach has LPV and LNAV, and the downgrade is required, the LNAV procedure on the same approach is followed and the same missed approach procedure is flown if needed. If the LPV does not have an LNAV option on the same chart, then the approach will be charted as Alternate Not Authorized with the black A symbol with the white A followed by NA.

I believe the reason for the 800-2 verses 600-2 has to do with the lateral guidance when there isn't a GS available. In the case of an ILS, it is still the localizer. In the case of the LPV, the localizer performance for lateral guidance is also downgraded to LNAV guidance and integrity, IOW the backup is more like a VOR than a localizer.

In any case, alternate minimums higher than the standard values will be used anytime the LNAV MDA or Localizer MDA is higher. Alternate minimums are based on worst case where the approach may still be flown. With an ILS, the only mandatory capability is that the localizer procedure may still be flown. With the LPV, the only mandatory capability is that the LNAV procedure may be flown.

There are two general kinds of system failures that the LPV will require a downgrade:

1) WAAS is available, but the integrity at the time of the approach does not support the LPV. Because of geometry, usually the vertical will fail before the lateral. For a DH of 200, VPL must be <35 meters and HPL must be <40 meters. The downgrade to LNAV only tests for HPL and it must be <556 meters.

2) WAAS is unavailable. This is extremely rare but happened once since the system was put on line for about a four hour period when a WAAS software update went bad. In this case, the default is to RAIM and standard GPS service applies. The RAIM must also be <556 meters (0.3 NM).

Thank you for the detailed clarifications/explanations.

 

[aterpster]

Thanks. So WAAS availability for LPV is considered less reliable than the GS for an ILS?
(Anecdotally I have personally experienced more GS failures than WAAS failures, but I guess that's not scientific.)

Not that simple. If an ILS is monitored, an alarm is sounded at some air traffic facility if there is a ground component failure. If it is unmonitored it cannot be used for alternate planning purposes. LPV is not monitored by any ATC facility. (no components to monitor.)

Which is more reliable is irrelevant for this purpose.

And, some ILS's are redundant, always monitored, and extremely reliable, such as the CAT II/III systems at some air carrier airports. OTOH, there are some air carrier airport ILS's that are not all that reliable, such as at LGA.

 

[aterpster]

That would be true if the RNAV(GPS) approach you're using has only LPV mins, but I've never seen one like that.

KYKM (Yakima, Washington) RNAV 27 X and W. One is LNAV only, the other is LPV only.

 

[luvflyin]

Yes. To have a DA of 200 feet, an LPV runway must have a parallel taxiway.

The siting criteria for ILS are much more strict. The FAA relaxed them to get LPV into Podunk airports provided the approach surfaces are clear.

For everyone: LPV is, in fact, a Category I precision approach. The issue is ICAO, not the FAA. The FAA is/was too nervous about upsetting the ICAO "apple cart." Perhaps this will change soon, now that Europe is going with LPV where they can (albeit more conservatively with airport standards, because they don't promote light airplane G/A over there.)

Why require a parallel taxiway? If the intent is to ensure that an aircraft doesn't back taxi into the glideslope critical area then why parallel? Any taxiway that exits the runway should be enough.

 

[aterpster]

Why require a parallel taxiway? If the intent is to ensure that an aircraft doesn't back taxi into the glideslope critical area then why parallel? Any taxiway that exits the runway should be enough.

That's not the intent. Many small airports have no way to exit the runway other than to back taxi into the face of another airplane on approach. Early in the program LPV was not allowed without a parallel taxiway.

 

[RotorDude]

KYKM (Yakima, Washington) RNAV 27 X and W. One is LNAV only, the other is LPV only.

Cool! Thanks for the example.

LPV only
LNAV only

 

[luvflyin]

That's not the intent. Many small airports have no way to exit the runway other than to back taxi into the face of another airplane on approach. Early in the program LPV was not allowed without a parallel taxiway.

So it's not still required? And why just DA's down to 200'. What is the current requirement?

 

[poadeleted20]

Thank you for the example. My assumption is that in your example, flying the GPS Z LPV and losing WAAS, you can't just quietly revert to the GPS Y LNAV on your own (though you can revert to GPS Z LNAV), since reverting to a different approach such as GPS Y means you'll be flying a different missed approach.

Correct.

I guess if you lose comms (or are nordo to start with) you could do that, but otherwise you'd need a new approach clearance (or a retroactive one, if there is such a thing) from ATC for the GPS Y.

Losing comm and then losing WAAS halfway down the approach? Definitely having a really bad day. But on the RNAV Y and Z into FDK, the approach fixes and course are the same either way, so ATC couldn't tell the difference if you switched, and if I've already lost comm and have now lost WAAS, a missed approach is no longer in my playbook -- I'm landing no matter what before things get even worse.

This used to be so simple when you just lost GS and reverted to LOC all on your own.

Well, if you lose WAAS while flying an LPV, you revert to LNAV on your own, so I don't see any significant
difference.

 

[poadeleted20]

So it's not still required? And why just DA's down to 200'. What is the current requirement?

200 DH (not DA) is the limit for all precision-type self-navigated approaches without either Cat II gear for ILS or LAAS for GPS. The accuracy limits of Cat I ILS and WAAS LPV just don't allow for a lower DH without compromising safety. Note that some PAR's have 100-foot DH's, but when we flew them in the military 30 years ago, they required a fully qualified 2-person side-by-side crew (i.e., OK in the A-6 and F-111 with pilot/WSO side-by-side, but not in the F-4 or RA-5C with pilot/WSO in tandem) to go below 200 DH.

 

[aterpster]

So it's not still required? And why just DA's down to 200'. What is the current requirement?

I believe not less than 250 and 1, but those types of policies keep changing.

 

[RotorDude]

Correct.

Losing comm and then losing WAAS halfway down the approach? Definitely having a really bad day. But on the RNAV Y and Z into FDK, the approach fixes and course are the same either way, so ATC couldn't tell the difference if you switched, and if I've already lost comm and have now lost WAAS, a missed approach is no longer in my playbook -- I'm landing no matter what before things get even worse.

Well, if you lose WAAS while flying an LPV, you revert to LNAV on your own, so I don't see any significant difference.

I agree if the LNAV you want is on the same approach plate. But if it's a different plate, and requires a different approach selected on the panel (either due to there being no LNAV on the LPV plate or as in your example the lower-mins LNAV you want is on a different plate), then it does get more complicated, esp. since it will likely require a clearance (if you are not nordo). I realize some ILS approaches don't revert to LOC-only on the same plate either, so I guess that would be somewhat similar.

 

[Turningfinal]

If it shows LPV, it's WAASified, and the KAP 140 will fly the LPV glide slope just the same as it does for an ILS glide slope.

Our club has a 2007 C172 G1000 with WAAS and a KAP140. The KAP140 will not couple to the LPV glide slope in our aircraft - only to lateral guidance. It will fully couple to an ILS however.

 

[John Collins]

The KAP140 and the KFC225 have a quirk that requires that the approach mode only be selected after the GS and other signals become active. In the GNS and GTN systems, this is called prompt mode. It has to do with the way the autopilot handles mode switches from GPS to Localizer mode. These autopilots were designed before there was vertical guidance available when using GPS, so the GPS has to fake the signals for an ILS on an LPV. When the head fake occurs, the autopilot detects a navigation source change and disconnects. Reengaging the autopilot a second time will overcome this, but the FAA did not think this was valid, so they required that a message be displayed to the pilot to be prompted to assert the signals followed by then selecting APR mode.

 

[poadeleted20]

I agree if the LNAV you want is on the same approach plate. But if it's a different plate, and requires a different approach selected on the panel (either due to there being no LNAV on the LPV plate or as in your example the lower-mins LNAV you want is on a different plate), then it does get more complicated, esp. since it will likely require a clearance (if you are not nordo).

True, but the number of approaches where LPV and LNAV are split on two charts seems to be miniscule.

I realize some ILS approaches don't revert to LOC-only on the same plate either, so I guess that would be somewhat similar.

Same -- a very few, but not many.

 

[poadeleted20]

Our club has a 2007 C172 G1000 with WAAS and a KAP140. The KAP140 will not couple to the LPV glide slope in our aircraft - only to lateral guidance.

As John said, it will, but it's not as straightforward as it could be, nor as straightforward as with ILS.

 

[Turningfinal]

As John said, it will, but it's not as straightforward as it could be, nor as straightforward as with ILS.

What's the process? I would love to be able to capture the LPV GS if it's capable....but nothing I've read in the KAP140 manual alludes to it.

I've waited until the needles were centered on the LPV approach before hitting "APR" mode but it only captures laterally.

I'm aware of the limitation of using GPS to the FAF then switching NAV sources - it will disconnect the autopilot - but no matter how many ways I've tried I've never been able to get the KAP140 in this WAAS G1000 172 to capture the LPV glideslope.

 

[poadeleted20]

What's the process? I would love to be able to capture the LPV GS if it's capable....but nothing I've read in the KAP140 manual alludes to it.

I've waited until the needles were centered on the LPV approach before hitting "APR" mode but it only captures laterally.

That's too late. You must select APR before the GS centers, but after it becomes active. The key, however, is being in NAV on the KAP 140 with ALT engaged rather than HDG with GPSS and then selecting APR and being in APR/ALT before the GS comes down. The problem arises when you are letting the GPS steer the plane and then select APR at the last minute. See the discussion on ILS capture in the KAP 140 book for details.

 

[Turningfinal]

That's too late. You must select APR before the GS centers, but after it becomes active. The key, however, is being in NAV on the KAP 140 with ALT engaged rather than HDG with GPSS and then selecting APR and being in APR/ALT before the GS comes down. The problem arises when you are letting the GPS steer the plane and then select APR at the last minute. See the discussion on ILS capture in the KAP 140 book for details.

We're talking G1000 here....I don't have a GPSS option. HDG mode with GPS as the active navigation source still follows the heading bug, and NAV mode will track the magenta if GPS is the active navigation source. Whether I arm APR mode before the FAF (after "LPV" is annunciated) or after the needles are centered it doesn't matter - it still only captures laterally. GS ARM isn't even annunciated.

A quick googling seems to show other people having the same issue with WAAS G1000 birds that still had the KAP140 autopilot. As far as I can tell, OP's instructor is correct because for the life of me I can't figure it out and I've been flying the KAP140 for 15 years now and consider myself very knowledgeable about its operation.

 

[poadeleted20]

We're talking G1000 here....I don't have a GPSS option. HDG mode with GPS as the active navigation source still follows the heading bug, and NAV mode will track the magenta if GPS is the active navigation source. Whether I arm APR mode before the FAF (after "LPV" is annunciated) or after the needles are centered it doesn't matter - it still only captures laterally. GS ARM isn't even annunciated.

A quick googling seems to show other people having the same issue with WAAS G1000 birds that still had the KAP140 autopilot. As far as I can tell, OP's instructor is correct because for the life of me I can't figure it out and I've been flying the KAP140 for 15 years now and consider myself very knowledgeable about its operation.

Well, it worked the last time I flew a G1000/KAP140 Cessna, so I don't know what to say.

 

[luvflyin]

200 DH (not DA) is the limit for all precision-type self-navigated approaches without either Cat II gear for ILS or LAAS for GPS. The accuracy limits of Cat I ILS and WAAS LPV just don't allow for a lower DH without compromising safety. Note that some PAR's have 100-foot DH's, but when we flew them in the military 30 years ago, they required a fully qualified 2-person side-by-side crew (i.e., OK in the A-6 and F-111 with pilot/WSO side-by-side, but not in the F-4 or RA-5C with pilot/WSO in tandem) to go below 200 DH.

That's not actually what I was wondering about. It was the requirement of a parallel taxiway to have a DH as low as 200. The reason was so aircraft could have a way to exit the runway without back taxiing on the runway into landing traffic. Seemed to me that DH. of say 250 or 300 would still make that an issue. I was wondering how high it need to be to remove the taxiway requirement. You did answer something I wondered about years ago though. I used to be a PAR controller at an airport with 100 and 1/4 mins but never saw an aircraft even attempt it below 200 and 1/2. It looks like you were Navy except for the F-111 reference.

 

[Velocity173]

200 DH (not DA) is the limit for all precision-type self-navigated approaches without either Cat II gear for ILS or LAAS for GPS. The accuracy limits of Cat I ILS and WAAS LPV just don't allow for a lower DH without compromising safety. Note that some PAR's have 100-foot DH's, but when we flew them in the military 30 years ago, they required a fully qualified 2-person side-by-side crew (i.e., OK in the A-6 and F-111 with pilot/WSO side-by-side, but not in the F-4 or RA-5C with pilot/WSO in tandem) to go below 200 DH.

So how did you all determine when your DH is 200 ft on a PAR? Just add 100 ft to DH and call missed if you didn't see anything? Radar altimeter?

All the PARs I gave in the Marines were 100 ft AGL regardless of aircraft type. It's in the radar approach mins section of the FLIP. There was no adjusting of the DH height call on the FPN-63 system. It's a fixed hash mark on the glidepath. You can actually see it in this pic.

 

[Turningfinal]

That's not actually what I was wondering about. It was the requirement of a parallel taxiway to have a DH as low as 200. The reason was so aircraft could have a way to exit the runway without back taxiing on the runway into landing traffic. Seemed to me that DH. of say 250 or 300 would still make that an issue. I was wondering how high it need to be to remove the taxiway requirement. You did answer something I wondered about years ago though. I used to be a PAR controller at an airport with 100 and 1/4 mins but never saw an aircraft even attempt it below 200 and 1/2. It looks like you were Navy except for the F-111 reference.

I'm not aware of any requirement to have a parallel taxiway to have a DH/DA as low as 200 ft.

Here's an LPV approach down to 200 ft. at an airport by me with no parallel taxiway:

http://155.178.201.160/d-tpp/1506/05990R7.PDF

And a CAT I ILS to a runway with no parallel:

http://155.178.201.160/d-tpp/1506/00652IL29.PDF

 

[luvflyin]

I'm not aware of any requirement to have a parallel taxiway to have a DH/DA as low as 200 ft.

Here's an LPV approach down to 200 ft. at an airport by me with no parallel taxiway:

http://155.178.201.160/d-tpp/1506/05990R7.PDF

And a CAT I ILS to a runway with no parallel:

http://155.178.201.160/d-tpp/1506/00652IL29.PDF

There was a post above that said it was a requirement. Guess it's not that simple

 

[luvflyin]

So how did you all determine when your DH is 200 ft on a PAR? Just add 100 ft to DH and call missed if you didn't see anything? Radar altimeter?

All the PARs I gave in the Marines were 100 ft AGL regardless of aircraft type. It's in the radar approach mins section of the FLIP. There was no adjusting of the DH height call on the FPN-63 system. It's a fixed hash mark on the glidepath. You can actually see it in this pic.

My guess is a barometric altimeter would have been just fine. It wouldn't surprise me if taking it down to 100 and the controllers call of decision height required a Radar Altimeter as well as 4 eyeballs in the front seat.

 

[John Collins]

I'm not aware of any requirement to have a parallel taxiway to have a DH/DA as low as 200 ft.

Here's an LPV approach down to 200 ft. at an airport by me with no parallel taxiway:

http://155.178.201.160/d-tpp/1506/05990R7.PDF

And a CAT I ILS to a runway with no parallel:

http://155.178.201.160/d-tpp/1506/00652IL29.PDF

The requirements can be found in AC 150/5300-13, Appendix 16, Table A16-1B. Approach Procedure With Vertical Guidance (APV-RNP), Approach Requirements.

If the visibility is under 1 SM, then a parallel taxiway is required. For visibility of 1 SM or greater, a parallel taxiway is only recommended. Note in your example, the visibility minimum is 1 SM, this is due to the lack of a parallel taxiway.

In a similar manner, for an ILS, Table A16-1A. Precision Instrument Approach Requirements lists that a runway without a parallel taxiway can not have a minimum visibility below 1 SM.

The tables specify other parameters such as the visual segment, runway length, lighting, runway marking, etc.

 

[poadeleted20]

It looks like you were Navy except for the F-111 reference.

Actually, I was Navy (A-6), ANG (RF-4C), and USAF (F-111). Not much for career potential, but a lot of fun while it lasted. And I've done some PAR's to 100-1/4 in the Intruder and 'Vark (one of which was a missed -- saw some concrete straight down before we started climbing on that one).

 

[poadeleted20]

So how did you all determine when your DH is 200 ft on a PAR? Just add 100 ft to DH and call missed if you didn't see anything? Radar altimeter?

Baro altimeter, and the mins were published in the Radar Minimums section of the approach book. If they gave only 100 DH mins, we added 100 to that to get the DA for the 200 DH mins. And if they gave only 200 DH mins, we weren't authorized to go lower on that PAR even if we were 100 DH-qualified.

 

[luvflyin]

The requirements can be found in AC 150/5300-13, Appendix 16, Table A16-1B. Approach Procedure With Vertical Guidance (APV-RNP), Approach Requirements.

If the visibility is under 1 SM, then a parallel taxiway is required. For visibility of 1 SM or greater, a parallel taxiway is only recommended. Note in your example, the visibility minimum is 1 SM, this is due to the lack of a parallel taxiway.

In a similar manner, for an ILS, Table A16-1A. Precision Instrument Approach Requirements lists that a runway without a parallel taxiway can not have a minimum visibility below 1 SM.

The tables specify other parameters such as the visual segment, runway length, lighting, runway marking, etc.

It looks like AC 150/5300-13A is the current document and Table 3-4 seems to combine what I'm guessing was in Tables A16-1A and A16-1B. This AC is about how you need to build your Airport if you want certain minimums. Do you know the paragraphs in the TERPS Manual that deal with this? The whole question started above in this thread when it was mentioned that a parallel taxiway was required to get a low DA.

 

[John Collins]

It looks like AC 150/5300-13A is the current document and Table 3-4 seems to combine what I'm guessing was in Tables A16-1A and A16-1B. This AC is about how you need to build your Airport if you want certain minimums. Do you know the paragraphs in the TERPS Manual that deal with this? The whole question started above in this thread when it was mentioned that a parallel taxiway was required to get a low DA.

Lower minimums, but not necessarily a lower DA would be more accurate. If there isn't a parallel taxiway, you need to be able to see further down the runway at the DA.

 

[aterpster]

It looks like AC 150/5300-13A is the current document and Table 3-4 seems to combine what I'm guessing was in Tables A16-1A and A16-1B. This AC is about how you need to build your Airport if you want certain minimums. Do you know the paragraphs in the TERPS Manual that deal with this? The whole question started above in this thread when it was mentioned that a parallel taxiway was required to get a low DA.

Scattered about such as:

Visual segment

Glieslope qualification surface

Some of the airport standards are incorporated into approach design by FAA internal policy, and sometimes how hard the airport manager pushes airport standards.

 

[luvflyin]

OK. Thanks for the info.

 

[olasek]

True. But are there any RNAV(GPS) approaches that have LPV minimums that do NOT have straight LNAV or LNAV/VNAV minimums? They might exist, I don't know for sure, but I've never encountered one.

That would be true if the RNAV(GPS) approach you're using has only LPV mins, but I've never seen one like that.

Well, I knew such examples exist though they are fairly rare, I was holding off until I was able to have one handy, here it is, there is no other RNAV(GPS) approach to runway 12 at LWS except the LPV, no LNAV or other variation.

I can't say I have run into this in real life, but I am pretty sure I have seen examples of separate plates for LPV vs. LNAV,

Correct, this is one example, except there is no plate for LNAV, none exists for rwy 12.

http://155.178.201.160/d-tpp/1506/00515RY12.PDF

 

[aterpster]

Well, I knew such examples exist though they are fairly rare, I was holding off until I was able to have one handy, here it is, there is no other RNAV(GPS) approach to runway 12 at LWS except the LPV, no LNAV or other variation.


Correct, this is one example, except there is no plate for LNAV, none exists for rwy 12.

http://155.178.201.160/d-tpp/1506/00515RY12.PDF

Note it has a 3.87 degree GS. That is why it is limited to Approach Categories A/B only. There is a terrain problem approaching that runway.

 

[Graueradler]

There are also differences in the required obstruction free zones off the end of the runway for various WAAS-LPV approaches. KRUE (Russellville, AR) has a WAAS-LPV to 7 with 275' and a mile vis requirements. We tried to get some approach lighting under the AIP program and were told that it wasn't elgible for funding unless it resulted in a reduction in required minimums. To get the improved minimums (less than 1 mile vis), we would also have to have acquired much greater avigation easements off of the end of the runway. Much greater cost so it didn't happen.

Our anticipated benefit from the lighting was simply to make the runway environment easier for the pilot to find once he broke out at mins. We have managed to add REILs.

 

[olasek]

Note it has a 3.87 degree GS. That is why it is limited to Approach Categories A/B only. There is a terrain problem approaching that runway.

OK, but it isn't clear why you could not have LNAV or circling with sufficiently high minimums. Once you leave FAF behind you a big flat valley opens up with plenty of room for maneuvering.

 

[aterpster]

OK, but it isn't clear why you could not have LNAV or circling with sufficiently high minimums. Once you leave FAF behind you a big flat valley opens up with plenty of room for maneuvering.

Because current FAA policy is not to chart CTL minimums on an IAP with only APV minimums. Note the same for the ILS.

You can fly an RNAV to a different runway, and CTL to Runway 12.