I just looked up this approach and it is a circling approach. The RNAV is to get you the 90% solution, but it’s up to you to do the final alignment and landing. Depending on your a/c category, pretty much if you don’t have the field in sight by ~10,200, you go missed and try again.
Thanks so much! I love this location and am excited to get a nice landing here.
I can see the two different plates.. the RNAV one.. and the LOC/DME one. They both have different points on the approach, with different headings. I flew the GPS one.. and was not aligned with the runway at all. It looks (on paper) like the other one maybe better? Why would they differ?
Not all approaches are runway aligned. Some require you to circle visually to align with the runway. These will have higher minima and vis requirements to ensure you can do this safely.
Circling approaches, especially at night, are actually some of the highest risk manoeuvres that IFR pilots are likely to conduct. Many companies prohibit them for this reason.
Straight in Approaches often have circling minima as well as straight in, so instead of flying the ‘long’ way around, you could fly an approach from the direction you are approaching the airport from, and just circle around to land in the other direction. This is usually reserved for non controlled airfields for obvious reasons.
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Different equipment and different minimums. It’s up to you to determine which approach is better for the weather and your aircraft. Also, in the real world you have to check NOTAMs as that LOC/DME might be out of service, leaving only the RNAV approach if you’re equipped to perform it.
wow, this is all good stuff here. I am learning..
Okay, I see now on the lower left of the chart where it says “circling” and I see where it says 10,200 next to it.
So this is where the bold black circle is referencing on the chart. (for some reason I thought that was the missed hold pattern).
So, how would this play out in flight?
GPS all the way to DBL? Cross DBL at 13,700’ then (at the same time as crossing DBL) activate heading mode and turn left flying 346?
But, then for how long? and for what reason. Then, turn right heading back 166. This would put me back on the same track again? I assume too I would be holding the same ALT during that circle? As the lower ALT are listed as the fixes continue towards the runway.
I know, what I just said is all wrong. lol. This is just how my brain computes it. I know you can set it straight 
EDIT…
Just thought about it again…
Maybe I need to just fly the fixes as listed.. at the ALT listed, and then when I get to 10,200 start the circle? (left 346), heading mode.. then, when I see I am aligned, AP off and hand fly it in? This would make logical sense. A way to burn the ALT, get lower and then setup for the final.
The circle at the top is a holding pattern at DBL, and is only required if you need it. Maybe ATC, or you’re too high and want to continue descending before commencing the approach. Or lastly, your approaching DBL from outside of +/-30°of the outbound track, in this case 166°. Then you’ll need a sector entry to align yourself correctly before continuing.
Assuming your under radar vectors, ATC will take care of this for you and position you to continue on 166°as soon as you arrive at DBL.
Keep the autopilot in NAV mode the whole time, and descend according to the chart. The minimum alt at MAFMU is 10200’ for a Cat A & B aircraft. Once at MAFMU, now “circle” which just means manoeuvre visually, similar to how you would in a circuit in VFR, to land on the runway.
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I have flown IFR since 2015, but this is what I remember (someone else I’m sure knows better):
The bold black circle is the IAP, you’ll do a holding pattern entry not lower than 13,700 before making the rest of the approach, crossing the other waypoints above the altitude listed.
Look up holding pattern entry and you’ll see the 3 methods you can use (direct, teardrop, parallel)
I see Norman, above, has a good explanation as I was typing this
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Thank you both so much! Got it. So, the bold is in fact a holding pattern (used for different reasons) at DBL and is not something that is required to complete a normal approach into this runway.
So, basically I did everything right.. except when I get down to 10,200 feet.. then, I should do a visual circle to turn all around and get aligned with the runway. So, this would likely be a right turn at that point, and this would also likely be manual hand flying at this stage, keeping a close eye on the speed and descent.
So I would re-fly this and do everything the same as before.. but, this time when I get to 10,200 in the descent, I will manually then fly a right turn circle to come around while still descending a bit to then land.
You’ve got it.
Unless the chart specifically states any restrictions on circling such as “not approved west of runway” than you’re free to manoeuvre however you like. Standard VFR circuit procedures and entry do not apply, as you should be the only aircraft there. The only restriction is you must remain within a certain distance from the runway depending on the speed of your aircraft.
If you feel you’re not to high and can make a dogleg right and land straight away that’s fine. Or you could join an upwind and complete a standard circuit if you’d prefer.
Edit: On this approach you’ve got about 2400’ to loose, and MAFMU looks about 2nm from the runway, so I’d definitely choose joining an upwind leg for a standard left had circuit, continuing to descend the whole time.
Whilst you’re free to manoeuvre however you like (you could make a right pattern if you’d prefer), the closer you can keep things to standard circuits, with familiar speeds, descent rates and configurations, the safer and easier the whole circling procedure becomes.
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You don’t have to wait for 10,200 either. That’s just a minimum; if you don’t have the runway in sight, that’s the point to declare a missed approach. I believe you can deviate before ALLIX, since you should be talking to tower by that point and likely already cleared to land.
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Yes, you are correct in your understanding. The main thing to take away is this – RNAV is not a precision instrument landing. It will get you close but not completely aligned. In many cases, it does. But that is not a guarantee.
The way I read the published approach for RNAV 15 @ KASE is that you need to have runway visibility by the time you get down to 10,200ft you need to have the field visible and visibility about 1 3/4 nm. If not, then you aren’t to land that approach and instead should be using LOC-DME-E approach, which will be a LOC approach that will bring you straight in to land rwy 15.
I would guess the reason the RNAV appraoch gets you in the ballpark and requires a visual circle to land is because there is only one runway, so shifting the RNAV aprpoach achieves separation and gives them 2 queues to put aircraft into.
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So if VNAV is basically vertical GPS where the autopilot automatically adjusts your altitude based on the waypoints does it work all the way down to actually landing the plane automatically ? If so what is the point in the autopilot approach mode if VNAV deals with the rate of descent/landing just fine ?
Don’t confuse anything we’ve been discussing with autopilot. Some APs can do these approaches, some cannot. Autopilot is only a tool to reduce pilot workload. Everything we’ve discussed to this point can be flown by hand, and that’s how you should learn to fly approaches in the first place
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Thank you for this! Let me ask another basic question.. the “LOC” I assume means localizer. When I hear this, I think “ILS”. (but I know its not). So, is there additional guidance avail to the plane when flying this approach? For example, can I use the “APPR” mode on the plane and it will auto descend like an ILS?
Also, I see that at the bottom of the LOC / DME chart.. it only list “circling” so.. does this mean that there is no such thing as a straight in landing at this airport?
I think this has more to do with the prescion of the method. ILS approach uses a local frequancy to guide the plane in. Its the most accurate of all. This is where you will need to use APPR. mode in the plane etc. GPS, on the other hand is not as accurate and the “resolution” of that approach is not the same. I know that this is not considered a precision landing method. So, while a few feet +/- up in the air is okay for way points, it becomes a different story when you get close to the ground and I think the required visibility is different for ILS vs. VNAV / RNAV etc
Also, not all planes with ILS can “Auto land” The A320 can.. but many can not.
Remember, LOC is a part of ILS. The LOC/DME approach has lower minimums for Cat A a/c and you will be on the runway centerline, but even then don’t go below or beyond your MAP without having the runway in sight. The FD/AP should have a LOC/BC mode for holding the LOC.
Compare this approach plate to something with a true ILS or LPV approach and look at how the different minimums and MAPs are identified (pick something into any large airport, for example). ILS systems are [supposedly] expensive to maintain, so a lot of local airports use approaches like this to get you close enough. In reality, if the weather is that bad, you’re heading to your alternate anyways, which should have better weather and/or more sophisticated landing aids.
Thank you! So, am I right in thinking that with a LOC/DME approach, I have an automated “guidance” in vertical, like ILS? All I need to do, is enter in the LOC frequency into NAV1, and press the LOC / APPR button in the AP and the plane should descend like it would on full ILS? Thus, would mean I could do RNAV all the way and then switch to NAV1 in the CDI when on the approach to get an assisted descent?
LOC/DME stands for Localizer, Distance Measuring Equipment. It is a type of precision instrument approach that provides for lateral (LOC) guidance, typically where the localizer is offset from the runway like you experienced at KASE. It does not provide vertical guidance.
While this is a great place to get feedback I’d also encourage you to satisfy your curiosity by learning from some established resources. Despite not being able to fly currently, as you mentioned, there is a huge opportunity to continuously learn the art and science (and regulations) of flying. When that day comes to begin your personal training journey, you will be that much better off. Here are a few suggested sites to further your interest in the instrument flight rules environment. There are plenty of others, of course:
http://www.flightsafety.org/asw/oct07/precision_approaches_web.pdf?dl=1
https://www.faa.gov/air_traffic/publications/atpubs/aim_html/index.html
https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/instrument_procedures_handbook/
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Thank you This is great info! I will bookmark these sites!
Absolutely! Aviation is my passion so I’m happy to help and share what I can!
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