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IAHFLYR
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RNAV (RNP) Approaches In The U.S.

Sun Feb 28, 2021 4:51 pm

You want Tech Ops, here ya go, sit back and take provide some feedback.

HISTORY:

Airplanes started to become more and more advanced with navigation solutions, some of us in ATC as well as the operators wanted to find ways to maximize these benefits based upon hours of flight sim trials proving repetitive lateral and vertical tracks using the Actual Navigation Performance (ANP) data as well as some early on trials from live flight data information. The result was (Required Navigation Performance) RNP approaches as well as SID/STARS. Even though the mention of other operators and airport did not surface in references to RNP work there were plenty of them behind the scenes.

https://en.wikipedia.org/wiki/Required_ ... erformance

Airports using multiple parallel runways simultaneously for arrivals in all weather ops, it was necessary to find ways to get the FAA and other alphabet groups (NATCA,SWAPA, APA, ALPA, NBAA etc.) to agree on the concept which was no small sell. Using the FAA controller handbook (7110.65) during dual and triple independent simultaneous ops as a reference some things had to be addressed and changed. Things such as having 1,000' of vertical separation until established on the final approach course which make sense, though also with the requirement for intercepting the glidepath from below created long downwind traffic and unnecessary delays in sequencing the traffic in order to provide this separation. Using three parallel runways made it worse as you had to go out further on downwind than using two runways due to the required altitudes (I know crazy restrictions). The more runways in use with parallels the more distance on downwind, period.

Some of us ATC'ers and airline flight tech folks started talking and along with some advances FAA thinkers in HQ (small number) decided to adopt a new translation of "established on the final approach course". We turned that in the RNP world to being established at a fix on downwind abeam the airport or close by where the majority of aircraft be configured and easily make the approach using Radius to Fix (RF legs) waypoints to descend and make a continuous turn back to intercept the final approach course outside the final approach fix (FAF). Aggressive, yes, saving time and distance, absolutely. The concept works great for those who equipped to fly RNP approaches and have qualified crews, those who did not equip are not penalized they simply get sequenced as they always have been sequenced.

APPLICATION

RNAV (RNP) Y RWY 9 at IAH.

https://aeronav.faa.gov/d-tpp/2102/0546 ... ddest=(IAH)

The controllers clears them for the approach prior to HOWLN and they are considered established on the final approach course once they are at HOWLN. Between HOWLN and TEXXN they are sent to the tower frequency long before they are actually on the runway centerline.

I took a snapshot of a few IAH arrivals landing RWY 8L/8R/9 the other day when the weather was marginal VFR to show the savings and constant lateral path of the approach though for some reason I cannot paste them in here, but have saved them to load once I figure it all out!!! :banghead: The aircraft flying the RNAV (RNP) RWY 9 starts the RF legs and turns about 11 miles from the airport while the ILS traffic that was ahead of them on the downwind is heading out to the west some 25-30 miles before getting their base leg turn and then on to the final. The RNP aircraft I watched were all B73G, B738 or B739 with a B73M tossed in as well while those who could not play in the RNP world were E145's and E175's.

Simply put, these type of procedures IMHO are worth equipping and crew training to utilize. As a controller it allows me to not have to vector and talk as much to focus on those other airplanes to tighten up the separation needed.

Thoughts and would love to hear from folks who have flown RNP approaches.
 
GalaxyFlyer
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Re: RNAV (RNP) Approaches In The U.S.

Sun Feb 28, 2021 6:51 pm

From a non-121 perspective, the FAA Flight Standards office needs to look at the approval process. Just every new bizjet has all the capability for RNP AR approaches, especially RF legs. Customers demanded it, then the regulators, no doubt with good intentions, made the process too onerous except for an operator whose trips regularly transit airports with AR approaches. I can the reasoning for a place like Aspen, lots of terrain problems, but IAH, spilling out of track is monitored by radar, nothing to hit, if the ATC function does its part. The technology is there, the error rate is manageable.
 
IAHFLYR
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Re: RNAV (RNP) Approaches In The U.S.

Sun Feb 28, 2021 9:42 pm

GalaxyFlyer wrote:
From a non-121 perspective, the FAA Flight Standards office needs to look at the approval process. Just every new bizjet has all the capability for RNP AR approaches, especially RF legs. Customers demanded it, then the regulators, no doubt with good intentions, made the process too onerous except for an operator whose trips regularly transit airports with AR approaches. I can the reasoning for a place like Aspen, lots of terrain problems, but IAH, spilling out of track is monitored by radar, nothing to hit, if the ATC function does its part. The technology is there, the error rate is manageable.


Well there is no "spilling out of track", it is extremely precise as you know. But there are things to hit should it occur, the other arrival to the middle runway!!! If I remember correctly the ANP normally found is something stupid like .03 track error which not even the best final monitor display/controller would ever see.

You are so very correct, Flight Standards does need a review of the approval process as well as many other things within their jurisdiction. :scratchchin:
 
Woodreau
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Re: RNAV (RNP) Approaches In The U.S.

Sun Feb 28, 2021 9:58 pm

I don’t know what their certification process is for the operator.

None of the regional airlines I flew for were authorized for RNAV(RNP) and the LCC I fly for isn’t authorized for them either.

We have RNAV visuals that make things easy like the Expressway Visual into LGA. The 7s and 19s for LAS.

The RNAV(RNP) 19 into DCA covers the river visual 19 keeps planes out of P-56 lasts long time.

So I wonder if it’s a certification process and the airlines don’t see the justification to get the authorization for it if it because it’s too hard or too expensive.
Last edited by Woodreau on Sun Feb 28, 2021 9:59 pm, edited 1 time in total.
 
GalaxyFlyer
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Re: RNAV (RNP) Approaches In The U.S.

Sun Feb 28, 2021 9:59 pm

It’s an RNP 0.30 procedure, the track guidance is very precise, but it’s not so difficult to use that it requires vast approval process. Heck, PRM approaches have lots of opportunity to hit the other arrival and not much in the way approval for operators. The system is missing out on improvements in flow management, especially at places like TEB. RF legs, regardless of RNP, are AR approaches and that really limits the flexibility. The AC90-101 implies the AR process is required because of reduced terrain, lateral and vertical, clearance surfaces.

The whole AC clearly sees the AR operator as an airline, a large one, that sees specific benefits that cost a lot of time and money. Complete audits of each NDB comparing the database with the government source material, for example.
 
DualQual
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Re: RNAV (RNP) Approaches In The U.S.

Mon Mar 01, 2021 12:51 am

I like them when they link directly from a STAR. There are no surprises as to how long the downwind (or how short) is going to be leading to either droning out forever or suddenly getting jammed into a base to final where you’ve been left high and probably fast. The only issue with them is they can be a bit onerous to set up in the FMC and brief and certain airports (looking at you DEN) like to advertise all the approaches as in effect so you’re left to guess what you’re actually going to get.
 
IAHFLYR
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Re: RNAV (RNP) Approaches In The U.S.

Mon Mar 01, 2021 12:55 pm

DualQual wrote:
I like them when they link directly from a STAR. There are no surprises as to how long the downwind (or how short) is going to be leading to either droning out forever or suddenly getting jammed into a base to final where you’ve been left high and probably fast. The only issue with them is they can be a bit onerous to set up in the FMC and brief and certain airports (looking at you DEN) like to advertise all the approaches as in effect so you’re left to guess what you’re actually going to get.


Indeed, having the runway transitions make it very easy and connecting up the approach a one key stroke according to what I was told and remember from very earl on testing in the sims.

https://aeronav.faa.gov/d-tpp/2102/0546 ... ddest=(IAH)

https://aeronav.faa.gov/d-tpp/2102/0546 ... ddest=(IAH)
 
DualQual
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Re: RNAV (RNP) Approaches In The U.S.

Mon Mar 01, 2021 5:25 pm

IAHFLYR wrote:
DualQual wrote:
I like them when they link directly from a STAR. There are no surprises as to how long the downwind (or how short) is going to be leading to either droning out forever or suddenly getting jammed into a base to final where you’ve been left high and probably fast. The only issue with them is they can be a bit onerous to set up in the FMC and brief and certain airports (looking at you DEN) like to advertise all the approaches as in effect so you’re left to guess what you’re actually going to get.


Indeed, having the runway transitions make it very easy and connecting up the approach a one key stroke according to what I was told and remember from very earl on testing in the sims.

https://aeronav.faa.gov/d-tpp/2102/0546 ... ddest=(IAH)

https://aeronav.faa.gov/d-tpp/2102/0546 ... ddest=(IAH)


In terms of loading and connecting the approach it is easy. However, when I said onerous, there are a few more steps that have to be accomplished (at least on my ride) to have the FMC set up for an RNP approach. I only mention it because it takes a little bit to get it loaded, do all the clean up work in the FMC (make sure the legs page is cleaned up correctly, altitudes and speeds are properly loaded, and any other box specific items that need to be taken care of for an RNP depending on the fleet).

On our side of the equation you’re probably looking at a minute or so to accomplish all that for a proficient crew that’s also familiar with the airport. That equates to about 3-4 miles of flying, minimum, in the terminal environment. I only bring that up to illustrate that changing things around in the moving metal tube isn’t just a one button exercise and we’re ready. It takes a few minutes.
 
IAHFLYR
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Re: RNAV (RNP) Approaches In The U.S.

Mon Mar 01, 2021 7:34 pm

DualQual wrote:
In terms of loading and connecting the approach it is easy. However, when I said onerous, there are a few more steps that have to be accomplished (at least on my ride) to have the FMC set up for an RNP approach. I only mention it because it takes a little bit to get it loaded, do all the clean up work in the FMC (make sure the legs page is cleaned up correctly, altitudes and speeds are properly loaded, and any other box specific items that need to be taken care of for an RNP depending on the fleet).

On our side of the equation you’re probably looking at a minute or so to accomplish all that for a proficient crew that’s also familiar with the airport. That equates to about 3-4 miles of flying, minimum, in the terminal environment. I only bring that up to illustrate that changing things around in the moving metal tube isn’t just a one button exercise and we’re ready. It takes a few minutes.


When you mention loading speeds and altitudes are you referring to verifying they match what is on the charts as most all of the RNP approaches I've seen have the altitude constraints contained within the procedure and some with speeds as well?

The "one button" comment was not intended to make light of what must be done on the flight deck, more so having runway transitions contained in the procedure does provide a smoother product in connecting it all up, would that be a more correct statement?
 
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Web500sjc
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Re: RNAV (RNP) Approaches In The U.S.

Mon Mar 01, 2021 9:01 pm

IAHFLYR wrote:
DualQual wrote:
In terms of loading and connecting the approach it is easy. However, when I said onerous, there are a few more steps that have to be accomplished (at least on my ride) to have the FMC set up for an RNP approach. I only mention it because it takes a little bit to get it loaded, do all the clean up work in the FMC (make sure the legs page is cleaned up correctly, altitudes and speeds are properly loaded, and any other box specific items that need to be taken care of for an RNP depending on the fleet).

On our side of the equation you’re probably looking at a minute or so to accomplish all that for a proficient crew that’s also familiar with the airport. That equates to about 3-4 miles of flying, minimum, in the terminal environment. I only bring that up to illustrate that changing things around in the moving metal tube isn’t just a one button exercise and we’re ready. It takes a few minutes.


When you mention loading speeds and altitudes are you referring to verifying they match what is on the charts as most all of the RNP approaches I've seen have the altitude constraints contained within the procedure and some with speeds as well?

The "one button" comment was not intended to make light of what must be done on the flight deck, more so having runway transitions contained in the procedure does provide a smoother product in connecting it all up, would that be a more correct statement?



Garbage in, garbage out. Loading an entire procure generally involves verifying the procedure in the box matches the current chart before letting the airplane fly the procedure. Occasionally the database has incorrect constraints or fixes. That being said- I prefer flying arrivals that hook up to the ILS and RNAV (GPS) approaches - much more predictability.
 
IAHFLYR
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Re: RNAV (RNP) Approaches In The U.S.

Tue Mar 02, 2021 2:45 pm

Web500sjc wrote:
Garbage in, garbage out. Loading an entire procure generally involves verifying the procedure in the box matches the current chart before letting the airplane fly the procedure. Occasionally the database has incorrect constraints or fixes. That being said- I prefer flying arrivals that hook up to the ILS and RNAV (GPS) approaches - much more predictability.


I completely understand crosschecking the database vs the chart for database errors, but would you explain what you mean with loading the entire procedure? The FMC I am most familiar with (very limited knowledge) is the Smiths Industry in the 73's and the procedures whether SID, STAR, Approach, MA procedures were all contained in the database and available in the DEP/ARR page etc., so there is my confusion.

When you refer to the ILS and RNAV (GPS) procedures being "much more predictable" my guess is you're referencing approach minima?

The approaches I was watching that got me thinking of the RNAV (RNP) was being flown with weather just below VFR so the minimums didn't much come into play, though the curved path RF legs certainly shortened the flight track for those able to qualify. Not sure the criteria for RNAV (GPS) approach procedures allows for RF legs, but I'll keep searching in coming days for them.

Thanks for your input and thoughts.
 
Woodreau
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Re: RNAV (RNP) Approaches In The U.S.

Tue Mar 02, 2021 4:18 pm

The thing that bothers me with the RNAV arrivals is that the landing runway changes the lateral track that is flown and sometimes the vertical descent profile.

The enroute controller at center tells us to descend via. So we ask what runway? Don’t know the approach controller will tell you. Contact approach...

Check on with the approach then they issue the landing runway. Now the vertical profile is fubar’ed. It not bad if you’re low but it’s a big pain if you’re now high after the runway change.

Or the approach controller tells you your landing runway is 28C. But fly the 27R runway transition... so now we’re forced to keep flying the 27R profile. And then when we get the vector. At 4000ft and 10 mile final The PM is now heads down fingering the box to get the 28C runway loaded. - not exactly hard but not instantaneous.
 
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Web500sjc
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Re: RNAV (RNP) Approaches In The U.S.

Tue Mar 02, 2021 4:36 pm

IAHFLYR wrote:
Web500sjc wrote:
Garbage in, garbage out. Loading an entire procure generally involves verifying the procedure in the box matches the current chart before letting the airplane fly the procedure. Occasionally the database has incorrect constraints or fixes. That being said- I prefer flying arrivals that hook up to the ILS and RNAV (GPS) approaches - much more predictability.


I completely understand crosschecking the database vs the chart for database errors, but would you explain what you mean with loading the entire procedure? The FMC I am most familiar with (very limited knowledge) is the Smiths Industry in the 73's and the procedures whether SID, STAR, Approach, MA procedures were all contained in the database and available in the DEP/ARR page etc., so there is my confusion.

When you refer to the ILS and RNAV (GPS) procedures being "much more predictable" my guess is you're referencing approach minima?

The approaches I was watching that got me thinking of the RNAV (RNP) was being flown with weather just below VFR so the minimums didn't much come into play, though the curved path RF legs certainly shortened the flight track for those able to qualify. Not sure the criteria for RNAV (GPS) approach procedures allows for RF legs, but I'll keep searching in coming days for them.

Thanks for your input and thoughts.



When we select the procedure, we first select the full procedure (ILS 8L at IAH), then you select what fix your starting the procedure from (GUSHR, MAAKO, Vectors), now procedure gets loaded into the FMS- and the pilots will
Verify the accuracy of the procedure and the legs involved. We Verify that the route goes GUSHR (@6000/210)-> BEPEA (Above 3000)->LIMEE (@3000)->Etc. We can’t just select the approach and not verify the procedure - if something unintended happened, the automation would follow the incorrect path. Some issues that were caught because of the leg verification- The database reverted to a very old database with inaccurate fixes, Someone selected the GPS Y instead of the GPS Z, I have accidentally selected the “ILS 36” at the departure airport instead the arrival airport.

There are a lot of options that can get fumbled around, to mitigate that we verify the approach in the box is the approach we want to do. Verification isn’t limited to approaches. We have to verify the accuracy when we change STARs, SIDS, and departure runways. Some STARS have 19 points along the expected routing that will be selected with 1 button push.

When I was referring to the GPS and ILS being more predictable- I was referring exclusively to approach procedures that connect to the end of a STAR. For instance, the ILS 8L at IAH has a potential start point of GUSHR. GUSHR is also the end of the GUSHR arrival, thus it is very predictable to connect the procedures together with no ATC vectoring involved. The same thing can happen with any approach.

Finally, RNAV (GPS) approaches do not allow for RF legs at the moment. RF legs are mostly found in RNAV (RNP) approaches, and a large amount of operators have not gone through the effort of acquiring the ability to fly RNAV (RNP) Approaches. At the moment, those RNP approaches don’t do have a large advantage over the ILS and GPS approaches present at the majority of US airports, they just add training and certification cost with no advantage. The US airlines that do have the capability to do RNAV (RNP) are a) generally larger (so they can spread the cost out), or b) operate in more mountainous areas where the RNP capability has significant advantages over conventional navigation.
 
e38
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Re: RNAV (RNP) Approaches In The U.S.

Tue Mar 02, 2021 4:49 pm

IAHFLYR, thank you very much for your narrative on the development of RNAV (RNP) approaches. Very interesting and informative.

With respect to your statement:

IAHFLYR wrote:
Thoughts and would love to hear from folks who have flown RNP approaches.


Basically, I think they're great; particularly the simplicity of the procedure. In the Airbus A320 series, on an RNAV or RNAV (RNP) procedure, when ATC says "cleared for the approach," we simply press two buttons--we select the APPR pushbutton to arm the approach and push for managed descent--and the rest is fairly automatic. Of course, there are a few additional items in terms of energy management and configuration, which would be characteristic of any approach, but the basics of the setup--RNAV (RNP)--are very straightforward.

The use of RNAV (RNP) procedures has also simplified training at the company at which I work. Previously, we would teach circling procedures during simulator training. There are several airports we serve where circling was required depending on winds and runway in use. For example, at Chicago Midway airport, when they are landing on the 22s, we previously flew the ILS or LOC approach to Runway 31C down to circling minimums, then turned to the northeast--circling maneuver--to enter a left downwind for Runway 22L. Now, ATC clears us to STERE intersection and we simply fly the RNAV (RNP) Y Rwy 22L approach to Midway. It's much easier than circling!

In addition, there are several airports in mountainous areas of the Western United States that do not have ILS approaches to certain runways due to terrain around the airport that prohibited a straight-in procedure. The implementation of RNAV (RNP) approaches at those airports, with the associated RF leg, has eliminated the need for the circling approach and allows for minimums that are lower than circling minimums. Many of these airports are in valleys and subject to low ceilings and reduced visibility. With the introduction of RNAV (RNP) procedures at these airfields, we have greatly reduced the number of diversions.

In fact, as a result of RNP procedures at these airports, we no longer feel a need to train the circling procedure at the training center and circling has been deleted from the training curriculum completely, freeing up valuable training time for other items.

Slightly off topic, but it was mentioned above there are more and more STARs that tie in to instrument approaches. I think these are outstanding as well. However, I've noticed they are not used consistently. Sometimes ATC will clear you for the approach while still on the STAR--this is what I prefer--while at other times, when approaching the end of the STAR, approach control will give a vector with a 30 degree intercept to the final approach course, an altitude assignment, and then clearance for the approach. It's not a big deal--we do this all the time--but I have to wonder why the controller could not just have left us on the procedure and given clearance for the approach--reduced communication, reduced workload on our part. My guess is perhaps they will do this as these procedures become more prevalent. As you probably know, they do this very well--and consistently--when landing at LAX, approaching from the east. It is not unusual for Los Angeles Center and/or SoCal approach control to issue clearance for the ILS 24R/25L while still 50-60 n.m. from the field.

Just wanted to let you know also that your post in Aviation Hobby, subject: "Why did you fall in love with aviation?" was excellent; thanks for sharing. Everyone has a story as to how they got from one point in their life to another--yours is especially interesting. Thanks.

e38
 
IAHFLYR
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Re: RNAV (RNP) Approaches In The U.S.

Wed Mar 03, 2021 2:29 pm

Web500sjc wrote:
When I was referring to the GPS and ILS being more predictable- I was referring exclusively to approach procedures that connect to the end of a STAR. For instance, the ILS 8L at IAH has a potential start point of GUSHR. GUSHR is also the end of the GUSHR arrival, thus it is very predictable to connect the procedures together with no ATC vectoring involved. The same thing can happen with any approach.

Finally, RNAV (GPS) approaches do not allow for RF legs at the moment. RF legs are mostly found in RNAV (RNP) approaches, and a large amount of operators have not gone through the effort of acquiring the ability to fly RNAV (RNP) Approaches. At the moment, those RNP approaches don’t do have a large advantage over the ILS and GPS approaches present at the majority of US airports, they just add training and certification cost with no advantage. The US airlines that do have the capability to do RNAV (RNP) are a) generally larger (so they can spread the cost out), or b) operate in more mountainous areas where the RNP capability has significant advantages over conventional navigation.


Oh, connecting up the STAR to the approach was something that was desired for quite some time and they finally did it AFTER I retired! :weeping:

Around these parts having the major airline certified to fly RNP approaches in a large percentage of the fleet does provide benefits such as I referred to in the original post as they are on the RF legs turning back to the airport 11-12 miles out while those who were not certified are flying a 28-30 mile downwind. But I get your point regarding the costs vs benefits.

Much appreciate your explanations.
 
IAHFLYR
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Re: RNAV (RNP) Approaches In The U.S.

Wed Mar 03, 2021 2:56 pm

e38 wrote:
In fact, as a result of RNP procedures at these airports, we no longer feel a need to train the circling procedure at the training center and circling has been deleted from the training curriculum completely, freeing up valuable training time for other items.

Slightly off topic, but it was mentioned above there are more and more STARs that tie in to instrument approaches. I think these are outstanding as well. However, I've noticed they are not used consistently. Sometimes ATC will clear you for the approach while still on the STAR--this is what I prefer--while at other times, when approaching the end of the STAR, approach control will give a vector with a 30 degree intercept to the final approach course, an altitude assignment, and then clearance for the approach. It's not a big deal--we do this all the time--but I have to wonder why the controller could not just have left us on the procedure and given clearance for the approach--reduced communication, reduced workload on our part. My guess is perhaps they will do this as these procedures become more prevalent. As you probably know, they do this very well--and consistently--when landing at LAX, approaching from the east. It is not unusual for Los Angeles Center and/or SoCal approach control to issue clearance for the ILS 24R/25L while still 50-60 n.m. from the field.

Just wanted to let you know also that your post in Aviation Hobby, subject: "Why did you fall in love with aviation?" was excellent; thanks for sharing. Everyone has a story as to how they got from one point in their life to another--yours is especially interesting. Thanks.

e38


Yes, we eliminated circling approaches many years back at IAH due to the fact we just never used them. But at places such as MDW and EWR with the approach to 22L circle 29 stuff the RNAV (RNP) Y and Z approaches provide a much more precise track allowing the EWR final controller to know exactly where the aircraft will fly rather which helps with sequencing.

As for why a controller doesn't allow the entire procedure when they connect form the STAR to the approach, it's hard to teach old dogs new tricks!!! :lol: Seriously though, some just don't believe the aircraft will be able to fly the procedure as well as what they think they can vector. Well, what about when they get busy and they blow an arrival through the final approach course.....it happens as you know. Had the controller allow the crew to use the runway transition to the final, not an issue.

I love reading those in the Hobby thread, love to see more of them. Thanks for the kind words.
 
N1120A
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Re: RNAV (RNP) Approaches In The U.S.

Wed Mar 03, 2021 10:33 pm

Given the advances in GA avionics, you'd think some of these RNP AR approaches would be made available to everyone.
 
IAHFLYR
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Re: RNAV (RNP) Approaches In The U.S.

Wed Mar 03, 2021 11:12 pm

[photoid][/photoid]
N1120A wrote:
Given the advances in GA avionics, you'd think some of these RNP AR approaches would be made available to everyone.


They are public procedures so technically they are available to all who are capable and authorized. The approval process does appear to require certain items such as alerting for certification, training and authorization.

https://www.faa.gov/documentLibrary/med ... _CHG_1.pdf

https://www.uasc.com/docs/default-sourc ... f?sfvrsn=2

Both of these are good reading though not sure AC 90-101A has been updated since it was first effective in 2016.
 
GalaxyFlyer
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Re: RNAV (RNP) Approaches In The U.S.

Thu Mar 04, 2021 1:43 am

Well, it’s complicated. For example, if the missed approach requires RNP 1.0 or less, you need an IRU. You must have a TAWS. The nav database must be verified by the operator and show the FAA your procedures for doing so; a simple download from the provider is not sufficient as it is for database downloads. You’ll have to have a compliant training program. You’ll probably have a table top review and exercise with the FSDO going thru your entire RNP AR program. It’s an interim approval until you demonstrate 100 RNP AR approaches. The whole AC is designed for airlines that get an operational advantage for having the OpsSpec.

RNP AR is nothing any other approval—CAT II, LPV, GPS, etc. So far, very few GA top-level bizjet operators are using them and nobody in the more common GA plane like piston or turboprop singles. It’s a shame because RNP could bring some great safety improvements at places like KTEB, KMDW, KSNA and tons of pure GA airports in mountainous terrain or noise-sensitive areas.
 
IAHFLYR
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Re: RNAV (RNP) Approaches In The U.S.

Thu Mar 04, 2021 1:56 pm

GalaxyFlyer wrote:
Well, it’s complicated. For example, if the missed approach requires RNP 1.0 or less, you need an IRU. You must have a TAWS. The nav database must be verified by the operator and show the FAA your procedures for doing so; a simple download from the provider is not sufficient as it is for database downloads. You’ll have to have a compliant training program. You’ll probably have a table top review and exercise with the FSDO going thru your entire RNP AR program. It’s an interim approval until you demonstrate 100 RNP AR approaches. The whole AC is designed for airlines that get an operational advantage for having the OpsSpec.

RNP AR is nothing any other approval—CAT II, LPV, GPS, etc. So far, very few GA top-level bizjet operators are using them and nobody in the more common GA plane like piston or turboprop singles. It’s a shame because RNP could bring some great safety improvements at places like KTEB, KMDW, KSNA and tons of pure GA airports in mountainous terrain or noise-sensitive areas.


I can't imagine not having to do a SMS review with FSDO and that in and of itself is painful experience.

Somewhat off topic, but when I was still working we had an operator that wanted CAT III certification and for sure FSDO had them flying 100 ILS approaches on our midnight shifts in a very very large corporate jet. Cannot imagine what the cost was, though they had a huge operation in other countries and needed it there.

Completely agree with your last paragraph, huge shame.
 
GalaxyFlyer
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Joined: Fri Jan 01, 2016 4:44 am

Re: RNAV (RNP) Approaches In The U.S.

Thu Mar 04, 2021 3:15 pm

There are lots of airports where using RNP procedures wouldn’t require the current review and approval process. There’s no such review for operators using LPV, LNAV, or an ILS. Perhaps a two stage process and something like today’s process for a category of approaches with a certain risk level—high density airports like KIAH or terrain like the mountain airports in ski areas. A charted RNP procedure at KTEB could be a safety improvement but isn’t utilized because of the process.

Doing a 100 CAT III ILSs at midnight strikes me more like “if we make this hard enough, they’ll go away with this crazy idea of a Part 91 autoland”. SMS review, fine we did them for RNP 4 and CPDLC, demonstrate competency in the sim and three in the plane, but a 100? That’s 25-30 hours of wasted time.
 
IAHFLYR
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Re: RNAV (RNP) Approaches In The U.S.

Thu Mar 04, 2021 4:30 pm

GalaxyFlyer wrote:
There are lots of airports where using RNP procedures wouldn’t require the current review and approval process. There’s no such review for operators using LPV, LNAV, or an ILS. Perhaps a two stage process and something like today’s process for a category of approaches with a certain risk level—high density airports like KIAH or terrain like the mountain airports in ski areas. A charted RNP procedure at KTEB could be a safety improvement but isn’t utilized because of the process.

Doing a 100 CAT III ILSs at midnight strikes me more like “if we make this hard enough, they’ll go away with this crazy idea of a Part 91 autoland”. SMS review, fine we did them for RNP 4 and CPDLC, demonstrate competency in the sim and three in the plane, but a 100? That’s 25-30 hours of wasted time.


To your point regarding airports with terrain issues:

http://www.boeing.com/commercial/aeroma ... laska.html

In all fairness, the hours we could support them flying a widebody during arrival banks was best done at those times since putting them into a long final was going to cost the operator even more time and money. During the midnight time which actually began around 2200 local time most nights unless weather caused delays, we let them build a racetrack patter with the downwind being 5 NM off the final approach course turning final at the fix located just before the FAF which was about 10 NM from the runway. They flew that for hours on end usually ending about four hours later on those nights they flew. If memory serves me correctly I do believe FSDO actually reduced the required number down some.
 
Thenoflyzone
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Re: RNAV (RNP) Approaches In The U.S.

Fri Mar 05, 2021 5:05 am

This is interesting. YYC started doing simultaneous RNP-AR approaches on its parallel runways back in 2018. I think it was a world first because it implemented a new ICAO standard: Established on RNP-AR (EoR).

The new standard enables simultaneous RNP-AR approaches without requiring a separation minimum of 1,000 feet vertically or 3 nm laterally, which the current conventional standard requires until the aircraft is established on final.

YYC was a perfect place to implement it, since over 40% of the traffic is RNP-AR capable (mostly because of WestJet and Encore). The numbers aren't that high for YYZ, YVR or YUL, due to a higher number of regional feeders and props that aren't certified for RNP-AR.

https://blog.navcanada.ca/world-first-n ... rd-at-yyc/

Pretty neat, and a good read. There's a cool video of the radar feed of the very first 2 planes doing their simultaneous RNP-AR approaches, both of them at almost the exact same altitude on their RF legs, turning inbound. (A WestJet B737 and Encore Q400)

GalaxyFlyer wrote:
From a non-121 perspective, the FAA Flight Standards office needs to look at the approval process. Just every new bizjet has all the capability for RNP AR approaches, especially RF legs. Customers demanded it, then the regulators, no doubt with good intentions, made the process too onerous except for an operator whose trips regularly transit airports with AR approaches. I can the reasoning for a place like Aspen, lots of terrain problems, but IAH, spilling out of track is monitored by radar, nothing to hit, if the ATC function does its part. The technology is there, the error rate is manageable.


I don't know how i feel about this. I know a lot of regional operators in my neck of the woods that could put themselves in harm's way if they tried an RNP AR approach in IMC conditions. Heck I've seen some of these guys attempt to fly an RNAV (GNSS) approach, and they were all over the place. Would hate to see them try a RF leg in IMC.

I don't know. The fact that it is over regulated might be a good thing.
 
IAHFLYR
Topic Author
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Re: RNAV (RNP) Approaches In The U.S.

Fri Mar 05, 2021 3:43 pm

Thenoflyzone wrote:
This is interesting. YYC started doing simultaneous RNP-AR approaches on its parallel runways back in 2018. I think it was a world first because it implemented a new ICAO standard: Established on RNP-AR (EoR).

The new standard enables simultaneous RNP-AR approaches without requiring a separation minimum of 1,000 feet vertically or 3 nm laterally, which the current conventional standard requires until the aircraft is established on final.

YYC was a perfect place to implement it, since over 40% of the traffic is RNP-AR capable (mostly because of WestJet and Encore). The numbers aren't that high for YYZ, YVR or YUL, due to a higher number of regional feeders and props that aren't certified for RNP-AR.

https://blog.navcanada.ca/world-first-n ... rd-at-yyc/

Pretty neat, and a good read. There's a cool video of the radar feed of the very first 2 planes doing their simultaneous RNP-AR approaches, both of them at almost the exact same altitude on their RF legs, turning inbound. (A WestJet B737 and Encore Q400)


Actually I believe YYC started back in 2015 according to Wiki. Check out "Established on RNP Approaches" section about a third of the way down.

https://en.wikipedia.org/wiki/Required_ ... erformance

This is the exact issue that got this thread started, the Established on RNP (EoR) concept which got the FAA to change Para 5-9-7 to allow EoR operations and what I was watching at IAH the night before I stated the thread:

SIMULTANEOUS INDEPENDENT APPROACHES- DUAL & TRIPLE

TERMINAL

A. Apply the following minimum separation when conducting simultaneous independent approaches:
1. Provide a minimum of 1,000 feet vertical or a minimum of 3 miles radar separation between aircraft :
(a) during turn-on to parallel final approach, or
(b) until aircraft are established on a published segment of an approach authorized for Established on RNP (EoR) operations.

NOTE-

Aircraft are considered EoR on an initial or intermediate segment of an instrument approach authorized for EoR operations after the approach clearance has been issued, read back by the pilot and the aircraft is observed on the published procedure (lateral and vertical path, and within any procedure specified speed restriction), and is conducting a simultaneous independent parallel approach with an authorized simultaneous instrument approach to a parallel runway.

REFERENCE-

FAA Order JO 7210.3, Para 10-4-6, Simultaneous Independent Approaches
P/CG Term – Required Navigation Performance (RNP)
P/CG Term – Established on RNP Concept

No long downwind for those able to use the RNAV (RNP) Y approach and they'd turn final alongside the other airplanes flying an approach (ILS, RNAV (GPS), RNAV (RNP) to RWY's 8 L/R not requiring the standard 1,000' of vertical separation normally required during the turn on to finals.

From the 7110.65 Pilot/Controller Glossory:

ESTABLISHED ON RNP (EoR) CONCEPT– A
system of authorized instrument approaches, ATC
procedures, surveillance, and communication requirements that allow aircraft operations to be safely
conducted with approved reduced separation criteria
once aircraft are established on a PBN segment of a
published instrument flight procedure.
 
IAHFLYR
Topic Author
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Re: RNAV (RNP) Approaches In The U.S.

Fri Mar 05, 2021 3:51 pm

GalaxyFlyer wrote:
but IAH, spilling out of track is monitored by radar, nothing to hit, if the ATC function does its part. The technology is there, the error rate is manageable.


There is no "spilling out" as I'm sure you know. If they get an alert on the flight deck, they tell ATC and then ATC takes over to get them away from the other aircraft unless an RA is received then they follow that command.

Thenoflyzone wrote:
I don't know how i feel about this. I know a lot of regional operators in my neck of the woods that could put themselves in harm's way if they tried an RNP AR approach in IMC conditions. Heck I've seen some of these guys attempt to fly an RNAV (GNSS) approach, and they were all over the place. Would hate to see them try a RF leg in IMC.


I would hope that the qualification requirements would be exactly the same as what WestJet and Encore had the equip and train for just like Alaska, United, American, Delta, jetBlue, Southwest Airlines to name a few have done here in the U.S.
 
FlyHossD
Posts: 2215
Joined: Mon Nov 02, 2009 3:45 pm

Re: RNAV (RNP) Approaches In The U.S.

Fri Mar 05, 2021 4:09 pm

IAHFLYR wrote:
DualQual wrote:
I like them when they link directly from a STAR. There are no surprises as to how long the downwind (or how short) is going to be leading to either droning out forever or suddenly getting jammed into a base to final where you’ve been left high and probably fast. The only issue with them is they can be a bit onerous to set up in the FMC and brief and certain airports (looking at you DEN) like to advertise all the approaches as in effect so you’re left to guess what you’re actually going to get.


Indeed, having the runway transitions make it very easy and connecting up the approach a one key stroke according to what I was told and remember from very earl on testing in the sims.


Done right, the RNAV RNP approaches can be a thing of beauty. But the set-up in the cockpit is somewhat more extensive than for an ILS approach. When DEN first started the RNAV RNP approaches, there were several examples of the approach assignment being given very late (already on the downwind leg) which resulted in errors and deviations. It's my understanding that this has long since been corrected.
 
IAHFLYR
Topic Author
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Re: RNAV (RNP) Approaches In The U.S.

Fri Mar 05, 2021 4:26 pm

FlyHossD wrote:
Done right, the RNAV RNP approaches can be a thing of beauty. But the set-up in the cockpit is somewhat more extensive than for an ILS approach. When DEN first started the RNAV RNP approaches, there were several examples of the approach assignment being given very late (already on the downwind leg) which resulted in errors and deviations. It's my understanding that this has long since been corrected.


When I was involved in some RNAV Task Force meetings years ago I remember well the chatter about late change we'd give to runways or transitions. If I remember there became a standard or was going to be that any changes in the box required no less than 10 NM from the new fix or IAF to a new runway. Inside of the 10 NM you had to get crew approval. Think that's how it came down then.
 
GalaxyFlyer
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Joined: Fri Jan 01, 2016 4:44 am

Re: RNAV (RNP) Approaches In The U.S.

Fri Mar 05, 2021 4:27 pm

Thenoflyzone wrote:
This is interesting. YYC started doing simultaneous RNP-AR approaches on its parallel runways back in 2018. I think it was a world first because it implemented a new ICAO standard: Established on RNP-AR (EoR).

The new standard enables simultaneous RNP-AR approaches without requiring a separation minimum of 1,000 feet vertically or 3 nm laterally, which the current conventional standard requires until the aircraft is established on final.

YYC was a perfect place to implement it, since over 40% of the traffic is RNP-AR capable (mostly because of WestJet and Encore). The numbers aren't that high for YYZ, YVR or YUL, due to a higher number of regional feeders and props that aren't certified for RNP-AR.

https://blog.navcanada.ca/world-first-n ... rd-at-yyc/

Pretty neat, and a good read. There's a cool video of the radar feed of the very first 2 planes doing their simultaneous RNP-AR approaches, both of them at almost the exact same altitude on their RF legs, turning inbound. (A WestJet B737 and Encore Q400)

GalaxyFlyer wrote:
From a non-121 perspective, the FAA Flight Standards office needs to look at the approval process. Just every new bizjet has all the capability for RNP AR approaches, especially RF legs. Customers demanded it, then the regulators, no doubt with good intentions, made the process too onerous except for an operator whose trips regularly transit airports with AR approaches. I can the reasoning for a place like Aspen, lots of terrain problems, but IAH, spilling out of track is monitored by radar, nothing to hit, if the ATC function does its part. The technology is there, the error rate is manageable.


I don't know how i feel about this. I know a lot of regional operators in my neck of the woods that could put themselves in harm's way if they tried an RNP AR approach in IMC conditions. Heck I've seen some of these guys attempt to fly an RNAV (GNSS) approach, and they were all over the place. Would hate to see them try a RF leg in IMC.

I don't know. The fact that it is over regulated might be a good thing.


If an airline crew, regional or major, can’t fly a standard RNAV (GNSS) approach, they shouldn’t be up there—it’s not different than any non-precision approach. BTW, I’ve flown hundreds of GPS, LPV approaches.
 
Thenoflyzone
Posts: 3145
Joined: Sun Jan 07, 2001 4:42 am

Re: RNAV (RNP) Approaches In The U.S.

Fri Mar 05, 2021 8:25 pm

GalaxyFlyer wrote:

If an airline crew, regional or major, can’t fly a standard RNAV (GNSS) approach, they shouldn’t be up there—it’s not different than any non-precision approach. BTW, I’ve flown hundreds of GPS, LPV approaches.


When i was still working approach control (until 2015), i saw several operators (including bigger players like Jazz, SkyRegional (when they had Q400s), etc) bust out of their RNAV(GNSS) legs from the downwind turn onto base leg (on a T shaped RNAV (GNSS) approach). Turns out they didn't have enough training for the procedure in the cockpit back then. They were plugging in the IAP waypoint as "fly over" instead of "fly-by", which made them bust out of the T shaped track connecting to the final. This was an issue, as the airport had higher terrain past the base leg.

Meanwhile, WestJet, who has been flying RNP AR approaches for over 10 years now (maybe even more), and had their own approaches charted out at the very same airport, were always spot on their RF legs, even in 40kt+ winds. (since 2018, there are now public RNP AR approaches available to anyone who is certified for it, but before this, WS had several dozen of their own RNP AR approaches across the country, especially at airports with terrain issues)

10+ years ago, these concepts were relatively new, so operators weren't all applying the proper procedures in the cockpit. I have since returned to my old APP unit on two occasions to give them a hand during peak summer months back in 2017 and 2018, and I saw a net improvement with the operators who can't do RNP AR approaches. No one was "spilling out" on the turn from downwind to base, or base to final.

So there is a net improvement, but seeing the issues they dealt with when it comes to standard RNAV GNSS approaches, I think the additional training/requirements for RNP AR approaches is warranted.

IAHFLYR wrote:

I would hope that the qualification requirements would be exactly the same as what WestJet and Encore had the equip and train for just like Alaska, United, American, Delta, jetBlue, Southwest Airlines to name a few have done here in the U.S.


Yes, it's the same. But if the requirements were relaxed (like GalaxyFlyer is suggesting), I could see some operators mess up the approaches. Probably less chance of it happening nowadays compared to 5 years ago, due to what I said above, but still.
 
IAHFLYR
Topic Author
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Re: RNAV (RNP) Approaches In The U.S.

Sat Mar 06, 2021 1:38 pm

Thenoflyzone wrote:
When i was still working approach control (until 2015), i saw several operators (including bigger players like Jazz, SkyRegional (when they had Q400s), etc) bust out of their RNAV(GNSS) legs from the downwind turn onto base leg (on a T shaped RNAV (GNSS) approach). Turns out they didn't have enough training for the procedure in the cockpit back then. They were plugging in the IAP waypoint as "fly over" instead of "fly-by", which made them bust out of the T shaped track connecting to the final. This was an issue, as the airport had higher terrain past the base leg.

Meanwhile, WestJet, who has been flying RNP AR approaches for over 10 years now (maybe even more), and had their own approaches charted out at the very same airport, were always spot on their RF legs, even in 40kt+ winds. (since 2018, there are now public RNP AR approaches available to anyone who is certified for it, but before this, WS had several dozen of their own RNP AR approaches across the country, especially at airports with terrain issues)

10+ years ago, these concepts were relatively new, so operators weren't all applying the proper procedures in the cockpit. I have since returned to my old APP unit on two occasions to give them a hand during peak summer months back in 2017 and 2018, and I saw a net improvement with the operators who can't do RNP AR approaches. No one was "spilling out" on the turn from downwind to base, or base to final.

So there is a net improvement, but seeing the issues they dealt with when it comes to standard RNAV GNSS approaches, I think the additional training/requirements for RNP AR approaches is warranted.


First issue is the crews should never have been putting in the waypoints period, they should all be contained in the database and be verified by the chart before they begin the procedure that way any coding issues would likely not occur such as you mention. There was an airline in the U.S. back in the early 2000's that would load the procedure from the database and then remove some of the waypoints for some unknown reason only to have to reinsert them into the procedure manually, boy did they make a mess of it and get some deviations filed against them until they fixed the issue with more training.

IAHFLYR wrote:

I would hope that the qualification requirements would be exactly the same as what WestJet and Encore had the equip and train for just like Alaska, United, American, Delta, jetBlue, Southwest Airlines to name a few have done here in the U.S.


Yes, it's the same. But if the requirements were relaxed (like GalaxyFlyer is suggesting), I could see some operators mess up the approaches. Probably less chance of it happening nowadays compared to 5 years ago, due to what I said above, but still.[/quote]

Not speaking for GalaxyFlyer, , but I imagine some of the approval process can be streamlined though training should never be reduced IMHO.
 
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Florianopolis
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Re: RNAV (RNP) Approaches In The U.S.

Sun Mar 07, 2021 1:08 am

If you can do your checkride in the sim, why can't you demonstrate the approaches for the approval in a simulator, too?
 
GalaxyFlyer
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Re: RNAV (RNP) Approaches In The U.S.

Sun Mar 07, 2021 1:21 am

Oceanic Ops using CPDLC, FANS1/A+ operators, airlines in the early days, had their problems with misunderstood messages and adherence to clearances—training and experience fixed it. There nothing easier than a crossing on FANS, but complacency will get you. Same with RNP AR, the traps should be pretty well known and understood by now. A decent training program, ground and sim, a table top with a qualified FSDO inspector should result in approval, assuming aircraft is equipped. If the FAA or other national authorities want to set aside some challenging airports for special qual, so be it. The French, Swiss and Austrians have special training required for Alpine airports. But, requiring the present process to fly a much safer visual approach to KTEB 01 than the circle now used is not safety-oriented.

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