8 minutes ago, KevinS137 said:

Interesting - what is the reason for not wanting to share these approaches with other airlines/pilots? Is it liability? Possible safety issues?

It's money. These procedures allow the airline to operate a reliable schedule to these airports, even in a climate that often produces low ceilings and visibility, with geography that doesn't allow for traditional straight in approaches. This airline invented the RNP (AR) approach, with the RNVM 26 to JNU being the first ever used with pax on board. Having these procedures is a significant competitive advantage... We can routinely get into these places when no one else can. It cost millions to develop this technology and these procedures, and they only did it because they expected a healthy return.

13 minutes ago, Stearmandriver said:

It's money.

I should've figured it was money, makes sense. That panhandle area is so fun to fly in the sim, must be so much better IRL. I think I'll go fly that milk run route again, haven't flown there in a while

I looked back and found I had downloaded these procedures in 2018:

RNP Approach Procedures for Southeast Alaska for use with the PMDG 737 NGX

Workaround waypoints for PMDG and RNP approaches.

Alaska Airlines unpublished procedures

Still in the Avsim Library.

https://library.avsim.net/search/basic/fsxmisc/alaska*

Edited July 21Jul 21 by vonmar

2 hours ago, Stearmandriver said:

I see what you're saying, and honestly I'm not sure how it would handle this with you being so close to the T/D. I'm not sure if the box wouldn't already be in descent phase by then, which would result in the error you're seeing because the hard 2000ft altitude violates the subsequent 2800A. It depends on where the box should be shifting from cruise to descent logic and I don't remember offhand.

What happens if you try that altitude modification before you've activated the route?

I think it's somewhere in the FMC logic that transitions from cruise to descent/terminal mode. Normally, it should happen at about 50% of the remaining distance to the destination or around 200 NM from the airport, which is pretty standard Boeing logic. It seems to be getting confused, though. I've tried it multiple times, and it's very hit-or-miss. There are definitely a few gremlins hiding in that box. 😄

15 hours ago, Stearmandriver said:

It's surprising in this case, if you know the history of this airline's vigorous defense of their intellectual property. There was a very high profile lawsuit launched by Delta against Alaska and the FAA about 13 years ago, in which Delta was suing for access to the approach data for Juneau. The judge, in his decision awarding Alaska the right to keep their IP private, stated that initially he considered this suit an easy win for Delta, but not only was his mind conclusively changed, he'd never seen such a vehement defense of IP rights by a corporation in his 30 years on the bench.

Fair enough.

Does no other airline have their own RNP approaches for those airports in Alaska? RNP approaches seem to be so ubiquitous now and many airlines have their own RNP approaches for other airports.

Edited July 21Jul 21 by RNAVV19R

4 hours ago, KevinS137 said:

Interesting - what is the reason for not wanting to share these approaches with other airlines/pilots? Is it liability? Possible safety issues?

Different companies handle this sort of thing differently. Some airlines develop their own RNAV Visuals or RNP approaches and make them available to other airlines, though I assume they do so for a fee. An example of this is the RNAV RNP 13L/R at KJFK. It was developed by JetBlue, but there are other airlines that have access to it.

7 hours ago, vonmar said:

I looked back and found I had downloaded these procedures in 2018:

RNP Approach Procedures for Southeast Alaska for use with the PMDG 737 NGX

Workaround waypoints for PMDG and RNP approaches.

Alaska Airlines unpublished procedures

Still in the Avsim Library.

Yup, those have been in the Avsim library at least since I found them probably around 2015. Don't know who released them. But these aren't those. Those files in the Avsim library are ancient now; basically every approach has been re-worked since then and there are many new procedures. Those Avsim files are also from a time when the PMDG couldn't handle RF segments, so they contain strings of the good old pseudo wayoints.

The procedures currently in Navigraph are considerably newer. Based on the layout of a few of them, and the existence or absence of certain transitions, I would say the navigraph procedures are from about mid to late 2024. I'm pretty sure they haven't been in Navigraph for that long, but that's the age of these versions of the procedures.

And I'm pretty convinced now that they weren't just picked up by automated spidering of some database. Not only are many procedures missing, but there's clear evidence of modification in a few of them. The RNVM 05 PSG is the best example; several waypoints are moved by over 500ft in order to slide the arc further away from terrain than it actually is. I suspect that's because the PMDG simply can't handle this procedure in its real-world form; this is the one where the PMDG actually hits a mountain. This procedure specifically, looks to have been tuned to make it kind of work with the PMDG. There's no other explanation; waypoint positions are never adjusted. If a procedure builder needs a point in a different position in reality, they just make a new point. The position of existing waypoints is never changed.

So, their inclusion in Navigraph isn't an accident. It's pretty brave, in fact. Anyone who enjoys these will probably want to save a backup of today's database, because it seems pretty likely they won't last if the company finds out.

I’m curious now. If one airline owns the IP for an approach, and specifically declines to share it with anyone else, could anyone else legally use it in real life?

4 hours ago, RNAVV19R said:

Does no other airline have their own RNP approaches for those airports in Alaska? RNP approaches seem to be so ubiquitous now and many airlines have their own RNP approaches for other airports.

Yep, there are a few other examples. One of the caravan operators out of JNU has a custom RNAV now (not an RNP AR because caravans can't do that). Delta is probably the best example; after losing their lawsuit, they developed a couple of their own approaches to JNU, before discovering they couldn't really make inroads in the market and pairing their schedule back to one flight a day during the summer only.

The funny thing is that winning the lawsuit wouldn't have done them any good as they probably couldn't have used the Alaska procedures anyway. All instrument procedures are built to a set of terrain-separation tolerances called the TERPS, and every procedure built by the FAA or a private operator must comply with the "public TERPS", the only one most folks ever see. But years ago after the Alaska RNP system had become mature, the FAA granted Alaska the authority to self-certify procedures to a unique TERPS criteria, a custom TERPS that accounted for the Alaska fleet specifically as equipped and flown. The public TERPS, being for everyone, has to basically account for the lowest common denominator of aircraft, and so it's a lot more restrictive than what Alaska is using now.

The upshot is that the Alaska procedures are allowed closer to terrain than anyone else's procedures, so minimums are a lot lower. The FAA at the time published a paper explaining their decision to allow this, in which they said it was necessary to provide reliable transportation and cargo operations to these communities (which are not reachable by road), but it was a one-time certification action they did not expect they'd ever see a reason to repeat with another airline. It's been about 20 years and so far they haven't.

Now I imagine if Delta or another large airline had a reason to pursue custom TERPS authorization, they could throw enough legal weight around to probably get it eventually. But it would be expensive and they just don't have an operational use for it; the couple markets it might matter in aren't enough to justify the expense. Heck, Southeast Alaska today is a small enough fraction of our overall route structure that it probably wouldn't be worth pursuing for Alaska either, but at the time it was achieved this was a different airline. The RNP system and custom TERPS represents decades of dedication to serving the state.

10 minutes ago, regis9 said:

I’m curious now. If one airline owns the IP for an approach, and specifically declines to share it with anyone else, could anyone else legally use it in real life?

Nope, that's the whole point. If you pay to develop the procedure, it's for your use and no one else's.

Westjet also has a number of their own RNP approaches into various Canadian airports. The best ones being in the mountains of British Columbia very similar to around PAKT.

Just now, Dave_YVR said:

Westjet also has a number of their own RNP approaches into various Canadian airports. The best ones being in the mountains of British Columbia very similar to around PAKT.

They do, yep. Iceland Air, Air New Zealand, and Norwegian are known for it too.

11 hours ago, Stearmandriver said:

I see what you're saying, and honestly I'm not sure how it would handle this with you being so close to the T/D. I'm not sure if the box wouldn't already be in descent phase by then, which would result in the error you're seeing because the hard 2000ft altitude violates the subsequent 2800A. It depends on where the box should be shifting from cruise to descent logic and I don't remember offhand.

What happens if you try that altitude modification before you've activated the route?

That 2800A at GRITY is the reason. It is not possible to have a higher crossing altitude following a lower one on a descent path.

6 hours ago, Stearmandriver said:

Nope, that's the whole point. If you pay to develop the procedure, it's for your use and no one else's.

Thanks that's what I figured, which is why I always wondered why it was so tightly guarded...it would seem to be useless to other real world aviators (while useful to us desk pilots 🙂 )

4 hours ago, regis9 said:

Thanks that's what I figured, which is why I always wondered why it was so tightly guarded...it would seem to be useless to other real world aviators (while useful to us desk pilots 🙂 )

Right. My guess is it's a holdover from a time when they were worried about other airlines being able to see the basic construction of the procedures, the techniques used etc. These days of course anyone can track all the flights in real time using any ads-b app, so the lateral and vertical flight paths are no kind of secret.