VATUSA Forums
General => The Control Room Floor => Topic started by: Wesley Miles on November 02, 2013, 10:19:29 PM
-
Who here issues "Descend Via" instructions to aircraft on an RNAV STAR working a CTR position? I spoke with a real world CTR controller recently who told me ARTCC's are not authorized to use that phraseology-- that it's reserved only for TRACONs (with the exception of ZAB... I believe). Has anyone else heard this? If so, where is the documentation?
When looking at 7110.65 4-5-7... it's pretty evident to me that "Descend Via" can be issued by either ENROUTE or TERMINAL. I know there was a notice (N JO 7110.584 (http://www.faa.gov/documentLibrary/media/Notice/N7110.584.pdf)) which added "Climb Via", then another notice which cancelled that (N JO 7110.597 (http://www.faa.gov/documentLibrary/media/Notice/N7110.597.pdf))... but neither appear to affect "Descend Via" which provides provisions for both Terminal and Enroute.
Thoughts?
-
I think that the 7110 is current in regards to descend via. ZDC uses it on a daily basis.
Out of curiosity, where does your source work?
-
If I remember correctly, he was at ZBW. Met him through VATSIM a few months ago but can't remember his name now.
-
ZLA has been using it for years. ZDV just started about a year ago with the introduction of RNAV STARs. "Climb via" is not approved. An IFR clearance containing an RNAV SID implies that the pilot will climb via the procedure unless otherwise instructed. I spoke to an FAA employee who works directly with the .65 a few months back, and he said there are numerous squabbles within the FAA as to how they want to address handling of RNAV procedures on the whole. I'd expect some changes within the next few years compared to how things are done now.
-
ZBW is unable to use "Descend via" with their RNAV arrivals due to conflicting traffic flows that cross their STAR routes. Boston TRACON issues the final "Descend via" instruction within the terminal environment once the aircraft's vertical path is clear of conflict.
Further reading on this specific to ZBW: http://nas-confusion.blogspot.com/2012/03/...-are-happy.html (http://nas-confusion.blogspot.com/2012/03/dont-worry-frogs-are-happy.html)
-
ZBW is unable to use "Descend via" with their RNAV arrivals due to conflicting traffic flows that cross their STAR routes. Boston TRACON issues the final "Descend via" instruction within the terminal environment once the aircraft's vertical path is clear of conflict.
Further reading on this specific to ZBW: http://nas-confusion.blogspot.com/2012/03/...-are-happy.html (http://nas-confusion.blogspot.com/2012/03/dont-worry-frogs-are-happy.html)
Depends on the situation. At 4am, with little or no traffic, they bend the rules a little at times. ie arrival on a STAR they use "at pilot discretion" and "decend via" a lot if there are no or little aircraft around. This comes from a friend that is a real world AA pilot.
-
Depends on the situation. At 4am, with little or no traffic, they bend the rules a little at times. ie arrival on a STAR they use "at pilot discretion" and "decend via" a lot if there are no or little aircraft around. This comes from a friend that is a real world AA pilot.
Not only that, but when you have a CTR position open handling the Terminal area (as APP), they are going to be issuing that instruction anyway. If APP is on, there will be that line of separation there as to who issues the call.
At most RW facilities, that position is always manned, so they never will run into that problem. For us, it is different, because it will never be manned 24/7.
Me personally, I'll issue the crossing restriction first, as required by SOP/LOA between the TRACON and ARTCC facility, and then after they meet that, give the 'descend via' call. If there is little/no traffic around at that time, I might give the 'descend via' all. I say 'might', because of what the initial crossing restriction may be.
Example: the SUNST3 arrival into KLAS explicitly has its first crossing restriction to be at FUZZY at 16000ft, 250kts. So for that one, again, if no traffic is around at all, give the 'descend via' call. Same would apply with the SEAVU2 arrival into KLAX.
However, the RIIVR2 arrival into KLAX, the first crossing restriction is at GRAMM at/below FL210, and at/above 17000ft, at 280kts. That would imply that a crossing restriction is needing to be given. So I may issue two separate calls, or combine them:
'Cross GRAMM at xxx' (depending on altimeter setting), then when they cross GRAMM, issue 'descend via'..
Or they could be combined: 'cross GRAMM at xxx, then descend via'.
For the latter, Las Vegas TRACON does issue that at times for aircraft that may be high or to give a bit of leeway on the SUNST3 or KEPEC3. They'll say something like 'cross IPUMY at 11,000, then descend via'.
BL.
-
However, the RIIVR2 arrival into KLAX, the first crossing restriction is at GRAMM at/below FL210, and at/above 17000ft, at 280kts. That would imply that a crossing restriction is needing to be given. So I may issue two separate calls, or combine them:
'Cross GRAMM at xxx' (depending on altimeter setting), then when they cross GRAMM, issue 'descend via'..
Wouldn't "Descend via the RIIVR2" allow an aircraft to cross GRAMM between 17,000 and FL210 at 280 KIAS? The block altitude doesn't necessitate a crossing restriction. Any SOP/LOA between ZLA and SCT would, however.
-
Wouldn't "Descend via the RIIVR2" allow an aircraft to cross GRAMM between 17,000 and FL210 at 280 KIAS? The block altitude doesn't necessitate a crossing restriction. Any SOP/LOA between ZLA and SCT would, however.
You're right, it would. However, you are also correct about SOPs. SCT has control on descent for the arrivals coming in on that STAR, and SOP does set a hard crossing altitude for the arrivals. so we issue that crossing restriction, and hand them off prior to crossing SCT's lateral boundaries, and let them handle that descent. When not available, we're acting as APP during the descent, so that would give the CTR controller a bit more leeway in how they would handle the descent.
BL.
-
Correct me if I am wrong, but my take on the descend via according to the 7110 is that if there is the word "expect" on the STAR either rnav and non-rnav, a controller cannot use the phrase "descend via". There are some rnav arrivals that have the word "expect with the crossing" and some do not. I believe DEN has a STAR that you can "descend via." Not sure there are many of those types around. According to real world FTW_CTR controllers DFW will be getting all new arrivals that will be rnav sometime in 2014. Currently, vZFW doesn't have any arrivals that would mandate a controller to use the phrase "descend via..." on the arrivals. I am hearing "decsend via" a lot in Vatusa where technicaly, this is incorrect in most cases.
-
Correct me if I am wrong, but my take on the descend via according to the 7110 is that if there is the word "expect" on the STAR either rnav and non-rnav, a controller cannot use the phrase "descend via". There are some rnav arrivals that have the word "expect with the crossing" and some do not. I believe DEN has a STAR that you can "descend via." Not sure there are many of those types around. According to real world FTW_CTR controllers DFW will be getting all new arrivals that will be rnav sometime in 2014. Currently, vZFW doesn't have any arrivals that would mandate a controller to use the phrase "descend via..." on the arrivals. I am hearing "decsend via" a lot in Vatusa where technicaly, this is incorrect in most cases.
You are quite correct here. But the other thing to realize is that they don't have to be RNAV for the airport in question.. it's mainly profiled descents that are the tale of the tape. Cases in point: RIIVR2 and SEAVU2 arrivals into LAX. The thing that I think is also confusing people is that the FAA has omitted using the word "cross at <altitude>", instead opting for the lines above, below, or both above and below the altitude depicted. So some controllers aren't used to seeing that, and may not know how to handle it.
BL.
-
Correct me if I am wrong, but my take on the descend via according to the 7110 is that if there is the word "expect" on the STAR either rnav and non-rnav, a controller cannot use the phrase "descend via".
... until after issuing "cross SMFIX at 10,000" (which is in the examples in this thread so far). That is, unless you're referring to a STAR that does not just begin with an "expect to cross at.." with hard crossing restrictions afterwards?
I am hearing "decsend via" a lot in Vatusa where technicaly, this is incorrect in most cases.
Any specific examples come to mind? To your point above, one example might be the VISTA2 (http://laartcc.org/charts/00237VISTA.PDF) arrival into KLAX.
With this STAR, saying "cross CYNDE at 12,000, then descend via the VISTA2 arrival" would be an example of an invalid instruction.
-
The Vista2 would not be a candidate for the "descend via..." phraseology. The words "Expect to cross..." invalidate the use of the phraseology if I am reading the 7110 correctly.
-
I've interpreted it as you can only issue the "descend via" instructions if the STAR has hard altitudes, (line above and below) otherwise you descend them manually. As for the OP. If the TRACON is staffed below, I don't see how Center can issue a "decend via" as it would bust the TRACON airspace, unless of course there is an SOP to that effect
-
The Vista2 would not be a candidate for the "descend via..." phraseology. The words "Expect to cross..." invalidate the use of the phraseology if I am reading the 7110 correctly.
Correct. You can't use it.
I've interpreted it as you can only issue the "descend via" instructions if the STAR has hard altitudes, (line above and below) otherwise you descend them manually.
Yup. See the FRDMM2 arrival into DCA. That's a "descend via" arrival.
-
I've interpreted it as you can only issue the "descend via" instructions if the STAR has hard altitudes, (line above and below) otherwise you descend them manually.
Yup. See the FRDMM2 arrival into DCA. That's a "descend via" arrival.
I'm going to strongly disagree with both of you on that point. Why must the altitude restriction be a hard restriction? Nothing in any FAA document states that, and that's certainly not the case with real-world controllers.
First example that comes to my mind would be the RIIVR2 (http://laartcc.org/charts/00237RIIVR.PDF) into KLAX. You're saying you won't hear "Descend via the RIIVR Two arrival" on LiveATC (or in ZLA on VATSIM ) countless times every day simply because the RIIVR intersection doesn't have a hard altitude?
EDIT: And just in case you try to get sneaky and claim that RIIVR is still a "boxed" altitude limit, I'll still argue that "Descend via the BASET3 (http://laartcc.org/charts/00237BASET.PDF) arrival" is perfectly fine as well despite the altitude restrictions at REEDR, DOWNE, etc.
EDIT2: After actually looking at the FRDMM2 arrival, I apparently misunderstand Ryan and/or both of you. My point was simply that a STAR could have zero "hard" altitudes and contain nothing but "at or above" altitudes and you'd still be able to use "descend via" with it. (Now, if the pilot acknowledges the instruction and never leaves his altitude, that's perfectly valid... he just probably won't get to land any time soon.)
-
I'm going to strongly disagree with both of you on that point. Why must the altitude restriction be a hard restriction? Nothing in any FAA document states that, and that's certainly not the case with real-world controllers.
First example that comes to my mind would be the RIIVR2 (http://laartcc.org/charts/00237RIIVR.PDF) into KLAX. You're saying you won't hear "Descend via the RIIVR Two arrival" on LiveATC (or in ZLA on VATSIM ) countless times every day simply because the RIIVR intersection doesn't have a hard altitude?
The reason it works for the RIIVR is that RIIVR is an IAF on approach plates. If you weren't clearing someone for the approach, you'd have to specify an altitude to descend to VIA the arrival... ala "Descend via the RIIVR2 arrival, maintain 10000."
[!--quoteo--][div class=\\\'quotetop\\\']QUOTE [/div][div class=\\\'quotemain\\\'][!--quotec--]EDIT: And just in case you try to get sneaky and claim that RIIVR is still a "boxed" altitude limit, I'll still argue that "Descend via the BASET3 (http://laartcc.org/charts/00237BASET.PDF) arrival" is perfectly fine as well despite the altitude restrictions at REEDR, DOWNE, etc.[/quote]
You can still descend via it, but again, you need to specify an altitude to maintain simply because the last published altitude is an at or above... "descend via the BASET3 arrival, maintain 8000."
[!--quoteo--][div class=\\\'quotetop\\\']QUOTE [/div][div class=\\\'quotemain\\\'][!--quotec--]EDIT2: After actually looking at the FRDMM2 arrival, I apparently misunderstand Ryan and/or both of you. My point was simply that a STAR could have zero "hard" altitudes and contain nothing but "at or above" altitudes and you'd still be able to use "descend via" with it. (Now, if the pilot acknowledges the instruction and never leaves his altitude, that's perfectly valid... he just probably won't get to land any time soon.)[/quote]
Yup.
-
I think it all just depends on your location and how the airspace is designed. Some airspace have profiled decent arrivals designed only for center, others have profiled decent arrival designed only for TRACON, some designed for both, some none at all.
-
At Memphis, CTR issues the "descend via" clearance, unless TRACON is online and specifically request for us to not do it, due to traffic, etc. We look at it as a default "green light" LOA, similar to DEL issuing departure clearances for all departure gates... unless TRACON specifically closes a gate.
I think the important thing to understand is that the LOA's are set up in the RW to maximize flow and efficiency. I am a firm believer that our LOA's do not necessarily have to be a carbon copy of the RW, as long as it works for us in the environment that we are working in. The "descend via" from En Route has been a huge time saver and made for a much more efficient TRACON environment. We just pop in "ARN" for 'descending via the arrival landing north', for example, in the scratch pad and that is pretty much it until it is time to turn the aircraft onto the approach.
Obviously not every airspace is setup for this, but for those that are, it is a very effective tool to use.
-
This statement pretty much sums it up. It can be found in the 7110.65 4-7-1 Altitude Information -
A descend via clearance must not be used where procedures contain published “expect” altitude restrictions.
-
This statement pretty much sums it up. It can be found in the 7110.65 4-7-1 Altitude Information -
A descend via clearance must not be used where procedures contain published “expect” altitude restrictions.
Be all/End all here. If the arrival doesn't call for it, they shouldn't do it, and should be up to the TAs of those sectors to make that clear, or get a bit of retraining done for when to use that for their STARs.
BL.
-
Thanks everyone for your input... I think that was a good discussion! I agree Brad/Tim... this topic is pretty much closed with that.
-
This statement pretty much sums it up. It can be found in the 7110.65 4-7-1 Altitude Information -
A descend via clearance must not be used where procedures contain published “expect” altitude restrictions.
This is the proper response to the question on DEN's procedures. The POWDR, LANDR, LARKS, QUAIL, SAYGE, TOMSN, RAMMS, and DANDD arrivals all have "Expect clearance to cross" information printed on the chart. We issue "Cross [fix] at and maintain [altitude]." Our new RNAV arrivals have crossing altitudes that make the use of "Descend via" appropriate.
[!--quoteo(post=0:date=:name=Kris Kendrick)--][div class=\\\'quotetop\\\']QUOTE (Kris Kendrick)[/div][div class=\\\'quotemain\\\'][!--quotec--]I think the important thing to understand is that the LOA's are set up in the RW to maximize flow and efficiency. I am a firm believer that our LOA's do not necessarily have to be a carbon copy of the RW, as long as it works for us in the environment that we are working in.[/quote]
The only thing that would be in an LOA would be crossing altitudes in the case of STARs with "Expect to cross [fix]" information. The use of "Descend via" would be contained in a facility SOP or addressed to controllers in training. I get your point, however.