All-PRNAV airports
Join Date: Sep 2003
Location: 59°45'36N 10°27'59E
Posts: 1,032
Likes: 0
Received 0 Likes
on
0 Posts
I donīt know any airspace where separation standards are connected to RNAV.
But: When working PRNAV flights there is less need to lock aircrafts on headings during "close" crossings etc. In our TMA I can climb one aircraft on a SID that is 6nm from a STAR without having to lock anyone on headings, i.e it is less workload intensive. (separation in such situations 5nm, not 3)
Same situation last year, before we went all PRNAV, you could not trust aircraft to stick to the SID/STAR centerline, and you had to radar vector much more, and by that creating much more workload.
But: When working PRNAV flights there is less need to lock aircrafts on headings during "close" crossings etc. In our TMA I can climb one aircraft on a SID that is 6nm from a STAR without having to lock anyone on headings, i.e it is less workload intensive. (separation in such situations 5nm, not 3)
Same situation last year, before we went all PRNAV, you could not trust aircraft to stick to the SID/STAR centerline, and you had to radar vector much more, and by that creating much more workload.
Join Date: Dec 2011
Posts: 2,460
Likes: 0
Received 0 Likes
on
0 Posts
you could not trust aircraft to stick to the SID/STAR centerline
Both DME/DME corrected INS, and GPS, are capable of keeping you (on autopilot) within a few tens of metres of the programmed track.
PRNAV does not in the slightest way affect lateral navigation accuracy.
Is this some ATC-procedural thing? Or perhaps you had airliners which were flying non-RNAV sids/stars using some old FMS which used VOR/DME as the nav source?
Join Date: Jan 2000
Location: PommyLand - but I'll be back!
Posts: 184
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for your input M609.
I don't understand, notwithstanding what Peter says, why a conventional or RNAV SID/STAR should require you to "lock anyone on headings" any more or less than the PRNAV version.
I don't understand, notwithstanding what Peter says, why a conventional or RNAV SID/STAR should require you to "lock anyone on headings" any more or less than the PRNAV version.
PPRuNe Bashaholic
Moderator
Join Date: Jun 1997
Location: The Peoples Alcoholic Republic of Jockistan
Posts: 1,442
Received 0 Likes
on
0 Posts
In domestic European airspace there is generally no different separation standard between aircraft based on their navigation capabilities. This is because they will either be separated or monitored by using radar (which is not dependent on aircraft fit), or by route structure (which is dependent upon the RNP value designated for the route).
Radar separation varies from 2.5NM on final approach to 10NM en route, or sometimes even greater.
Route separation is mostly based on BRNAV at the moment, which is RNP-5.
For radar monitored parallel RNP-5 routes, ICAO suggest a minimum distance between the route centre lines of 10NM-15NM. In practice, I think our UK designers go for 12NM. If it is that spacing or more, then monitoring is all that is required. If it is less, then the routes are not deemed separated and our rules usually say that appropriate radar or vertical separation must be provided.
For RNP-5 routes which are separated procedurally, and the only 'surveillance' is from pilot position reports, the ICAO recommendation is 16.5NM between the centre lines for uni-directional routes and 18NM for bi-directional routes.
PRNAV equates to RNP-1. I have not seen any formal confirmation yet, but previous concept documents I have seen were suggesting that for radar monitored RNP-1 routes, the spacing would be 7NM and for procedural routes would be 10NM.
In TMA airspace, even lower RNP values might be achievable, but by interpolation of guidance material, would still only offer a slightly decreased route separation value, which in any case could never come below the separation standard value of the surveillance equipment being used. If you went for RNP-0.3, the minimum route separation for routes which are monitored by surveillance would be in the order of 3.6NM for uni-directional routes. You would then of course have to assess the risk of being able to pass a corrective action in the event of a deviation between aircraft only 3.6NM apart in enough time to prevent a collision. Fortunately that kind of decision is way above my pay grade
Radar separation varies from 2.5NM on final approach to 10NM en route, or sometimes even greater.
Route separation is mostly based on BRNAV at the moment, which is RNP-5.
For radar monitored parallel RNP-5 routes, ICAO suggest a minimum distance between the route centre lines of 10NM-15NM. In practice, I think our UK designers go for 12NM. If it is that spacing or more, then monitoring is all that is required. If it is less, then the routes are not deemed separated and our rules usually say that appropriate radar or vertical separation must be provided.
For RNP-5 routes which are separated procedurally, and the only 'surveillance' is from pilot position reports, the ICAO recommendation is 16.5NM between the centre lines for uni-directional routes and 18NM for bi-directional routes.
PRNAV equates to RNP-1. I have not seen any formal confirmation yet, but previous concept documents I have seen were suggesting that for radar monitored RNP-1 routes, the spacing would be 7NM and for procedural routes would be 10NM.
In TMA airspace, even lower RNP values might be achievable, but by interpolation of guidance material, would still only offer a slightly decreased route separation value, which in any case could never come below the separation standard value of the surveillance equipment being used. If you went for RNP-0.3, the minimum route separation for routes which are monitored by surveillance would be in the order of 3.6NM for uni-directional routes. You would then of course have to assess the risk of being able to pass a corrective action in the event of a deviation between aircraft only 3.6NM apart in enough time to prevent a collision. Fortunately that kind of decision is way above my pay grade
Join Date: Sep 2003
Location: 59°45'36N 10°27'59E
Posts: 1,032
Likes: 0
Received 0 Likes
on
0 Posts
Or perhaps you had airliners which were flying non-RNAV sids/stars using some old FMS which used VOR/DME as the nav source?
Our "old" stars where conventional with RNAV overlay, and even on straight sections of stars some customers often wandered off centerline 2-3nm, and when asked said they where "on magenta line". Back then we did not focus much on the RNAV status on the aircraft, but surprise-surprise when we went PRNAV last year, the handling of BRNAV flights singled out some customers, and the "offenders" was all among them.
You are right that many BRNAV a/c are fully capable of flying very accurately, which is nice for us, but as long as some don't, we can't count on it.
And that brings us to what GWYN asks about.
On BRNAV procedures experience shows that a/c often overshoots turns with several miles, even on fly via points, not all the time, but several times each day. On PRNAV procedures my experience is that a/c nail the turns rolling out on the next segment each time.
(When it happens nowadays, the crew mostly confess to having gone into heading mode or some such, and not trusting the box. Or cancelling the procedure in the FMS, and wandering off whilst trying to put it back in, without telling ATC
)When i have a SID that turns parallell to a STAR with say 7nm, any overshoot on that turn will mean a loss of separation, so with BRNAV you would never design them that close, or you would use vertival separation until the turn was observed to be accurate, or turn the departure onto the desired heading earlier to assure separation. Hence increase worload.
With PRNAV procedures that are properly designed, you can IMHO shift more aircraft in a given volume of airspace with the same staff and ATM equipment.
But: For GA IFR you will as peter correctly states seldom fly a SiD or STAR, and the issue is speed. Modern terminal procedures are designed to manage a even flow of aircraft, i.e capable of flying arrivals at speeds in the low 200s in clean config. Departures will often see the use of "prop" SIDs for turboprops, since performance is more diverse in climb.
In your GA hotship tourer you will often be the slow boy, even for prop departures, and ATC want to move you away from the flow.
Join Date: Dec 2011
Posts: 2,460
Likes: 0
Received 0 Likes
on
0 Posts
M609 - I think what you describe by e,g,
is something pretty weird going on, and it either creates big questions about how crappy nav gear they have in [some] airliners, or the pilots weren't using it.
I know that INS (without GPS corrections) can easily be a few nm off track on oceanic routes but this should never happen over mainland Europe.
Basically, when the procedure track is loaded (either from the database or by manually loading the waypoints) the aircraft should be within about 1/4 mile on all sections where major turns are not taking place. That is where I would be, with a crappy mid-1990s GPS and a late-1990s autopilot.
And I have no GPSS / roll steering. All modern jets (those that can fly holds on autopilot for example) ought to have computed turns.
Something very weird is going on...
What seems to have happened for you with PRNAV introduction is not really PRNAV introduction but a change of cockpit procedures to actually use the stuff they have had for many years. Even with VOR tracking one should not be 2nm off track (at say < 30D) unless somebody is not paying attention, or they are using a dodgy avionics shop
PRNAV is a boat which left the harbour about 15 years ago. The fact that GPS/RNAV approaches are equivalent to RNP0.3 makes PRNAV, with its massive costs, a pointless exercise. Even at GA level, PRNAV cannot be done for less than 5 digits and for most IFR aircraft it will mean a huge retrofit - for no extra functionality but just to get the "boxes" for which the manufacturer has produced the PRNAV LoA (etc). But in this business there are always people who are looking for work and PRNAV is a good gravy train to jump on. Almost as good as AIDS research...
and even on straight sections of stars some customers often wandered off centerline 2-3nm,
I know that INS (without GPS corrections) can easily be a few nm off track on oceanic routes but this should never happen over mainland Europe.
Basically, when the procedure track is loaded (either from the database or by manually loading the waypoints) the aircraft should be within about 1/4 mile on all sections where major turns are not taking place. That is where I would be, with a crappy mid-1990s GPS and a late-1990s autopilot.
And I have no GPSS / roll steering. All modern jets (those that can fly holds on autopilot for example) ought to have computed turns.
Something very weird is going on...
What seems to have happened for you with PRNAV introduction is not really PRNAV introduction but a change of cockpit procedures to actually use the stuff they have had for many years. Even with VOR tracking one should not be 2nm off track (at say < 30D) unless somebody is not paying attention, or they are using a dodgy avionics shop
PRNAV is a boat which left the harbour about 15 years ago. The fact that GPS/RNAV approaches are equivalent to RNP0.3 makes PRNAV, with its massive costs, a pointless exercise. Even at GA level, PRNAV cannot be done for less than 5 digits and for most IFR aircraft it will mean a huge retrofit - for no extra functionality but just to get the "boxes" for which the manufacturer has produced the PRNAV LoA (etc). But in this business there are always people who are looking for work and PRNAV is a good gravy train to jump on. Almost as good as AIDS research...
Join Date: Jan 2000
Location: PommyLand - but I'll be back!
Posts: 184
Likes: 0
Received 0 Likes
on
0 Posts
Interesting stuff. Thanks M609 for your explanations. Peterh, I'm with you all the way up to the AIDS research. AIDS, Malaria etc. are still serious diseases and deserving of research and the type of fundamental research involved often produces discoveries and benefits not necessarily related to the original research subject. Now if you were to start talking about the general level of panic and hysteria surrounding AIDS, BSE, Avian 'flu, SARS, Volcanic Ash, etc., etc., and the predicted mass fatalities resulting, I would definitely be with you on that as well.
I still don't understand the claimed benefits of PRNAV though. M609, you state that, "With PRNAV procedures that are properly designed, you can IMHO shift more aircraft in a given volume of airspace with the same staff and ATM equipment." I respect your opinion as one who is apparently involved at the 'sharp end' of this but you do say that this is only your opinion. Is there any real evidence that this is the case and if so I still don't really understand how.
You also however say that, "(When it happens nowadays, the crew mostly confess to having gone into heading mode or some such, and not trusting the box. Or cancelling the procedure in the FMS, and wandering off whilst trying to put it back in, without telling ATC." So even with PRNAV there is, of course, still no guarantee that aircraft will be where the procedure says they should be. So all of the design to put tracks closer together seems simply to be a degradation of safety.
Surely, "When i have a SID that turns parallell to a STAR with say 7nm, any overshoot on that turn will mean a loss of separation, so with BRNAV you would never design them that close, or you would use vertival separation until the turn was observed to be accurate, or turn the departure onto the desired heading earlier to assure separation. Hence increase worload. " if the tracks are that close, then it would be foolhardy in any case, PRNAV or not, to not have an element of vertical separation for just the reason which you describe.
As a related remark in all this I could mention at least one airline, which while PRNAV equipped and approved, chooses not to put the "P" on the FPL as the PRNAV procedures add so much extra track mileage that it would add significantly to costs.
While we are on this type of subject and have M609's attention, perhaps you would give us your take on another of the dreams of the 'Gravy train committees,' the 'point merge' procedures? What on earth is that all about?
10W, you make exactly my point: there is no difference in separation standards and in European airspace aircraft are continuously radar monitored. So what is the benefit of PRNAV, RNP - and ADSB in Europe, come to that?
Back when I were a lad and things were simple(r), they larned I at skool, that an airway was a corridor of airspace whose limits were defined vertically and which extended five miles either side of the centreline, i.e was 10nm wide. I am still unclear as to whether this has changed or what effect all this RNP stuff actually has in practice. I still don't really see how it improves 'flight efficiency' which is another of the committees' 'metrics.' I hope you appreciate my use of all the jargon!
It is interesting that, 10W, you also state that, "In TMA airspace, even lower RNP values might be achievable, but by interpolation of guidance material, would still only offer a slightly decreased route separation value, which in any case could never come below the separation standard value of the surveillance equipment being used." So you agree that what is really important is the surveillance equipment being used, i.e. radar, not so much what is on the aircraft or what it is called. Ultimately the limits, particularly in a congested TMA, are mostly defined by physical constraints, particularly separation required due to wake turbulence requirements and no amount of mandating upgraded on-board equipment is going to change that. Only a change in aircraft design or maybe the laws of physics! As to procedural separation, I would be interested to know where, in European non-oceanic airspace, there is normally en-route procedural separation.
I still don't understand the claimed benefits of PRNAV though. M609, you state that, "With PRNAV procedures that are properly designed, you can IMHO shift more aircraft in a given volume of airspace with the same staff and ATM equipment." I respect your opinion as one who is apparently involved at the 'sharp end' of this but you do say that this is only your opinion. Is there any real evidence that this is the case and if so I still don't really understand how.
You also however say that, "(When it happens nowadays, the crew mostly confess to having gone into heading mode or some such, and not trusting the box. Or cancelling the procedure in the FMS, and wandering off whilst trying to put it back in, without telling ATC." So even with PRNAV there is, of course, still no guarantee that aircraft will be where the procedure says they should be. So all of the design to put tracks closer together seems simply to be a degradation of safety.
Surely, "When i have a SID that turns parallell to a STAR with say 7nm, any overshoot on that turn will mean a loss of separation, so with BRNAV you would never design them that close, or you would use vertival separation until the turn was observed to be accurate, or turn the departure onto the desired heading earlier to assure separation. Hence increase worload. " if the tracks are that close, then it would be foolhardy in any case, PRNAV or not, to not have an element of vertical separation for just the reason which you describe.
As a related remark in all this I could mention at least one airline, which while PRNAV equipped and approved, chooses not to put the "P" on the FPL as the PRNAV procedures add so much extra track mileage that it would add significantly to costs.
While we are on this type of subject and have M609's attention, perhaps you would give us your take on another of the dreams of the 'Gravy train committees,' the 'point merge' procedures? What on earth is that all about?
10W, you make exactly my point: there is no difference in separation standards and in European airspace aircraft are continuously radar monitored. So what is the benefit of PRNAV, RNP - and ADSB in Europe, come to that?
Back when I were a lad and things were simple(r), they larned I at skool, that an airway was a corridor of airspace whose limits were defined vertically and which extended five miles either side of the centreline, i.e was 10nm wide. I am still unclear as to whether this has changed or what effect all this RNP stuff actually has in practice. I still don't really see how it improves 'flight efficiency' which is another of the committees' 'metrics.' I hope you appreciate my use of all the jargon!
It is interesting that, 10W, you also state that, "In TMA airspace, even lower RNP values might be achievable, but by interpolation of guidance material, would still only offer a slightly decreased route separation value, which in any case could never come below the separation standard value of the surveillance equipment being used." So you agree that what is really important is the surveillance equipment being used, i.e. radar, not so much what is on the aircraft or what it is called. Ultimately the limits, particularly in a congested TMA, are mostly defined by physical constraints, particularly separation required due to wake turbulence requirements and no amount of mandating upgraded on-board equipment is going to change that. Only a change in aircraft design or maybe the laws of physics! As to procedural separation, I would be interested to know where, in European non-oceanic airspace, there is normally en-route procedural separation.
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
creates big questions about how crappy nav gear they have in [some] airliners
If your in heading mode, basically crew cockup, turn points are missed, wind changes arn't spotted and the tracking goes off. Alot of the machines you can't slave the AP to the GPS or if you do you use the VOR capture mode which I have already said is the work of satan and would make me feel sick never mind the punters in the back.
The only thing that will sort this is by tightening up the instrument limits and having a third party instrument C of A every 12 months which the airlines will lobby like
not to have. If say you report a 5 knts split between airspeed indicators they won't actually fix it because the limit is 6 knts each ASI is allowed +- 3 knts. And then you get the sodding machine does something different in the air than it does on the test rig on the ground. There are several levels of LNAV in my experence.
1. Go get straight line only which the controllers will spot because they get to a point then turn if the crew are leaving the machine to do its own thing.
2.You get circular nav which means they can fly dme arcs and holds etc. But will still go to the point then turn
3. And then you get the predictive turn ones which have logic to swing by points and start turns before you get to the point and will also vary the distance to the point when the turn is wound in depending on the GS and angle to be turned through.
Sometimes it can be the same hardware but with a different software level. But they won't upgrade it because that would cost 50k.
Then there is training, some training folk say you can't start turning until you with x amount of a point this can vary between 0.5 miles and 5. I have looked for a reference for this years ago but couldn't find it. Then you have crews taking the piss and cutting the corner edging round it from 10 miles out.
Join Date: Dec 2011
Posts: 2,460
Likes: 0
Received 0 Likes
on
0 Posts
OK, an interesting lesson on supposedly crappy airliner avionics (I would have my two VOR receivers adjusted if they were more than 1 degree out on the 30 day FAA mandatory VOR check; it is a simple matter of getting an IFR4000 tester and removing one of the four fixing screws) but I don't see the connection with PRNAV improving things for ATC because the aircraft must be BRNAV approved and you cannot do that with just VOR receivers.
My comment about AIDS research was flippant, GWYN Just referring to how many people would be out of a job if the problem was ever solved.
My comment about AIDS research was flippant, GWYN
Just referring to how many people would be out of a job if the problem was ever solved.
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
BRNAV is for area navigation not terminal navigation. Basically below FL100 your not meant to use it (but we all do). SIDS and STARS will all reference a radio aid if you do a PRNAV SID and STAR the points can just be abstract points in space with no reference to a radio aid.
Thats my understanding on it anyway.
Without PRNAV they have to expect that the aircraft will deviate to the max of the allowed instrument error so each nav aid will have a one dot cone coming out of it which is the max deviation. Then from the edge of that cone they then seperate to the max edge of another cone.
Which is actaully where some noise planners fall foul because they prescribe routes which are outside the nav tolerances of the aircraft.
Thats my understanding on it anyway.
Without PRNAV they have to expect that the aircraft will deviate to the max of the allowed instrument error so each nav aid will have a one dot cone coming out of it which is the max deviation. Then from the edge of that cone they then seperate to the max edge of another cone.
Which is actaully where some noise planners fall foul because they prescribe routes which are outside the nav tolerances of the aircraft.
Join Date: Dec 2011
Posts: 2,460
Likes: 0
Received 0 Likes
on
0 Posts
BRNAV is for area navigation not terminal navigation. Basically below FL100 your not meant to use it (but we all do). .
BRNAV is a certain level of lateral accuracy. It is available to you whenever you are flying according to some form of track guidance.
Are you saying there are passenger or cargo jets flying in Europe which fly using the FMS (i.e. INS with DME/DME or GPS corrections) when enroute, and after they cross the terminating waypoint of the enroute section, and if flying a non RNAV STAR, they track VORs until the IAF?
If so, who is doing that and what in?
If that is really common then I can see PRNAV is a huge spanner in the works because they will all have to rip out most of their panel.
Any half decent GA IFR tourer can auto-fly (perhaps with the pilot hand turning the course pointer, if he has a mechanical HSI and doesn't have GPSS) the whole enroute and terminal path with ~ 1/4nm lateral accuracy all the way to the IAF and then intercept and track the ILS to 200ft AGL.
SIDS and STARS will all reference a radio aid if you do a PRNAV SID and STAR the points can just be abstract points in space with no reference to a radio aid
Join Date: Jan 2000
Location: PommyLand - but I'll be back!
Posts: 184
Likes: 0
Received 0 Likes
on
0 Posts
BRNAV is for area navigation not terminal navigation. Basically below FL100 your not meant to use it (but we all do). That's a bit of a surprise. Where did that come from?
This is all very entertaining but apart from M609's considered opinion, we don't seem to be unearthing the underlying benefits of PRNAV and how it is going to unlock capacity.
Mad jock (is there another sort??? - only joking! Please take it as such.) also touches on another point: increased accuracy in flying the SID can have the effect of concentrating the noise. This has already happened: where noise was acceptable because it was spread, increased adherence to the precise SID has meant that the same (groups of) houses are always receiving the whole noise benefit of jets at full chat.
This is all very entertaining but apart from M609's considered opinion, we don't seem to be unearthing the underlying benefits of PRNAV and how it is going to unlock capacity.
Mad jock (is there another sort??? - only joking! Please take it as such.) also touches on another point: increased accuracy in flying the SID can have the effect of concentrating the noise. This has already happened: where noise was acceptable because it was spread, increased adherence to the precise SID has meant that the same (groups of) houses are always receiving the whole noise benefit of jets at full chat.
Join Date: Dec 2011
Posts: 2,460
Likes: 0
Received 0 Likes
on
0 Posts
I was talking to a fairly senior ATCO at LHR during an ATC visit at West Drayton (several years ago) and he said PRNAV is a load of crap because ATC will always radar vector traffic.
He explained (and this has also been written by other ATCOs known to be senior on the UK scene) that if radar failed, the capacity of all these airports would instantly collapse to a fraction of the present. So they have very good backups for their radars.
That makes complete sense, but it beggars belief that so much effort has been expended into designing 42 STARs (just counted them) for LHR, which are probably never actually flown, and 32 SIDs which are probably partly flown before radar vectoring takes over.
Interestingly, none of the LHR STARs are RNAV, never mind PRNAV. So what is it that has driven the all-PRNAV airports when Heathrow, which is claimed to be the busiest on the earth / the universe / etc seems to manage with procedures which you could fly in a stock 1970 C150
Could it be that the LHR STARs are never actually flown as published, whereas at say Vienna they have gone for ludicrously convoluted RNAV transitions (but I notice they still retain radar vectoring for "non RNAV" aircraft)?
Do they have a different class of aircraft going into LOWW which can perfectly self-separate by flying at 220kt +/- 1kt (or whatever), all tracking the RNAV tracks with perfectly computed and wind-corrected fly-by and fly-through waypoint performance? I know s0d-all about airline autopilots but I understand that even the new ones do not fly precisely calculated wind corrected track intercepts. I know the capability exists on fairly modern avionics to do this in zero wind...
Or, just perhaps, has somebody created a lot of work by designing all these procedures which, should they actually have to be operated for real, the said airport's capacity will collapse?
When I last flew into Zurich (another similar place) they assigned me a PRNAV SID which I refused but they just said "fly the overlay". No overlay is published but the message was clear (ATC there couldn't care less).
But surely this issue will not go away, because most jets fly mostly on autopilot and navigation with modern kit is now so accurate that one jet could fly into the back of another one, if timed procedural separation (as over e.g. Africa) failed.
He explained (and this has also been written by other ATCOs known to be senior on the UK scene) that if radar failed, the capacity of all these airports would instantly collapse to a fraction of the present. So they have very good backups for their radars.
That makes complete sense, but it beggars belief that so much effort has been expended into designing 42 STARs (just counted them) for LHR, which are probably never actually flown, and 32 SIDs which are probably partly flown before radar vectoring takes over.
Interestingly, none of the LHR STARs are RNAV, never mind PRNAV. So what is it that has driven the all-PRNAV airports when Heathrow, which is claimed to be the busiest on the earth / the universe / etc seems to manage with procedures which you could fly in a stock 1970 C150
Could it be that the LHR STARs are never actually flown as published, whereas at say Vienna they have gone for ludicrously convoluted RNAV transitions (but I notice they still retain radar vectoring for "non RNAV" aircraft)?
Do they have a different class of aircraft going into LOWW which can perfectly self-separate by flying at 220kt +/- 1kt (or whatever), all tracking the RNAV tracks with perfectly computed and wind-corrected fly-by and fly-through waypoint performance? I know s0d-all about airline autopilots but I understand that even the new ones do not fly precisely calculated wind corrected track intercepts. I know the capability exists on fairly modern avionics to do this in zero wind...
Or, just perhaps, has somebody created a lot of work by designing all these procedures which, should they actually have to be operated for real, the said airport's capacity will collapse?
When I last flew into Zurich (another similar place) they assigned me a PRNAV SID which I refused but they just said "fly the overlay". No overlay is published but the message was clear (ATC there couldn't care less).
increased adherence to the precise SID has meant that the same (groups of) houses are always receiving the whole noise benefit of jets at full chat.
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
Define FMS though your NG's and new airbuses have them and heavys but most of your regional stuff doesn't have them. I don't know what the Q400 and Saab2000 has they are as about as new as you get for regional TP kit.
The 146 etc don't have them.
Normally you need the VOR up for setting up the hold as you come to the end of the star.
Heading into a procedural field you would have the vor up on primary again for joining the hold and for your outbound. You can't decend until you get half scale deflection.
Certainly the 15 departure from BHX heading north was always a flurry of DME holds and VOR's getting tuned in.
LHR ATC are not always the best ones to ask because they are working in a very controlled enviroment. Ask a controller from Newcastle,Leeds or the like and you will get a different responce. Its a very British thing to radar vector everything. The likes of Helsinki or Oslo you will get given an approach and you will complete it without another word said once cleared for it apart from QSY to tower.
The 146 etc don't have them.
Normally you need the VOR up for setting up the hold as you come to the end of the star.
Heading into a procedural field you would have the vor up on primary again for joining the hold and for your outbound. You can't decend until you get half scale deflection.
Certainly the 15 departure from BHX heading north was always a flurry of DME holds and VOR's getting tuned in.
LHR ATC are not always the best ones to ask because they are working in a very controlled enviroment. Ask a controller from Newcastle,Leeds or the like and you will get a different responce. Its a very British thing to radar vector everything. The likes of Helsinki or Oslo you will get given an approach and you will complete it without another word said once cleared for it apart from QSY to tower.
Join Date: Mar 2001
Location: I wouldn't know.
Posts: 4,498
Likes: 0
Received 0 Likes
on
0 Posts
Saab 2000 new? Its out of production for 10 years now. The 146 even longer. Both are basically gone in most of europe, nowadays its jungle jets or Q400s, the odd ATR inbetween. Most of those have a full FMS and are of course completely PRNAV aproved.
Anyway, while vectors are common, transitions are widely used now as well. And some airports use quite a lot of their STARs as well. As mad_jock says many scandinavian airports use STARs and only very rarely use vectors. Even though major german airports do not use STARs they do use transitions, which have usually two opposite directions which are pretty closely spaced, oh VIE does as well. Was quite surprised on my first approach to gothenburg to get nearly 80NM out a clearance for SID and ILS, next was the frequency change to tower and a landing clearance there. Very quiet approach, but worked very nice.
Anyway, while vectors are common, transitions are widely used now as well. And some airports use quite a lot of their STARs as well. As mad_jock says many scandinavian airports use STARs and only very rarely use vectors. Even though major german airports do not use STARs they do use transitions, which have usually two opposite directions which are pretty closely spaced, oh VIE does as well. Was quite surprised on my first approach to gothenburg to get nearly 80NM out a clearance for SID and ILS, next was the frequency change to tower and a landing clearance there. Very quiet approach, but worked very nice.
Join Date: Jan 2000
Location: PommyLand - but I'll be back!
Posts: 184
Likes: 0
Received 0 Likes
on
0 Posts
But surely this issue will not go away, because most jets fly mostly on autopilot and navigation with modern kit is now so accurate that one jet could fly into the back of another one, if timed procedural separation (as over e.g. Africa) failed.
I thought someone would pick up on the converse and say that surely if these procedures are so accurate, then surely that means the noise can be concentrated in the (maybe uninhabited) other areas. Swings and roundabouts, I guess.http://images.ibsrv.net/ibsrv/res/sr...s/embarass.gif
You are of course correct on both points: it will not go away and also, yes your other point is correct too, although it doesn't necessarily need a failure of procedural separation. See http://www.pprune.org/rumours-news/2...er-brasil.html, GOL 737 vs Legacy over Brazil. Head-on rather than into the back of the other but you will understand my point.
I say again, though: this is all very entertaining but apart from M609's considered opinion, we don't seem to be unearthing the underlying benefits of PRNAV and how it is going to unlock capacity. I have added 'point merge' to that question now as well.
The rest of the discussion is interesting but does not really answer the question, "What's it for Mister?"
I thought someone would pick up on the converse and say that surely if these procedures are so accurate, then surely that means the noise can be concentrated in the (maybe uninhabited) other areas. Swings and roundabouts, I guess.http://images.ibsrv.net/ibsrv/res/sr...s/embarass.gif
You are of course correct on both points: it will not go away and also, yes your other point is correct too, although it doesn't necessarily need a failure of procedural separation. See http://www.pprune.org/rumours-news/2...er-brasil.html, GOL 737 vs Legacy over Brazil. Head-on rather than into the back of the other but you will understand my point.
I say again, though: this is all very entertaining but apart from M609's considered opinion, we don't seem to be unearthing the underlying benefits of PRNAV and how it is going to unlock capacity. I have added 'point merge' to that question now as well.
The rest of the discussion is interesting but does not really answer the question, "What's it for Mister?"
Join Date: Dec 2011
Posts: 2,460
Likes: 0
Received 0 Likes
on
0 Posts
The basic point is that you don't need PRNAV to end up with an avionics fit where your autopilot can track a preloaded arrival track.
My old KLN94 ($5k or so when new) can do all this, except it doesn't have the RNAV procedures whole in its database (it has the waypoints by name). An almost equally ancient GNS430 does have them (AFAIK) so that's you done and dusted.
No need for PRNAV.
My old KLN94 ($5k or so when new) can do all this, except it doesn't have the RNAV procedures whole in its database (it has the waypoints by name). An almost equally ancient GNS430 does have them (AFAIK) so that's you done and dusted.
No need for PRNAV.