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AF330

Rnav navigation

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Hi everyone!

Rnav routes are used to go faster and without navigation from VOR to NDB to VOR...

There are T roures and Q routes and both use GPS or IRS/INS.

 

But could anyone explain what is the difference between an airway and an RNAV airway?

They both fly from waypoints to waypoints, don't they?

 

Thanks!

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But could anyone explain what is the difference between an airway and an RNAV airway?

 

Hi, AF330,

 

I haven't come across this terminology.  Would you be kind enough to point to an example where it is used?

 

That being said, I will hazard a guess: a non-RNAV airway can be navigated using VORs and perhaps NDBs -- any intersection on it must be specified by a distance and radial from a VOR, or by the intersection of two VOR radials or by two intersecting directional lines drawn from NDBs. A few years ago I flew on a DC9 out of Atlanta, which appeared to not have RNAV capabilities.  When I later looked up the SID flown, it consisted completely of VOR radial intersections.  So I'm guessing that the same principle applies to airways.

 

An RNAV airway can have all sorts of waypoints that are not defined by external radio signals.

 

Just a guess.

 

Mike

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Hi,

Are the waypoints not always NDB, VOR's? Or is there something else?

Will just give an example in a few minutes, just searching...

And do the waypoints without radio signals have a name?

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NAV Canada refers to them as 'RNAV Airways'.  A really good example can be found in Alberta, between Edmonton and Calgary, where the old routes were replaced with RNAV T and Q routes.  I've been flying them in the sim now for awhile, but I'm not an expert on them.  The entry / exit waypoints on the new routes simply coincide with the new terminal arrival entry points.

 

For my little bit of experience (completely inside the sim), the new routes are easy enough to follow, but look super confusing on the hi or low charts.

 

A useful document for Alberta:

 

http://www.navcanada.ca/EN/products-and-services/On%20Board/AASP%20Phase%203%20Customer%20Readiness%20Document%20Effective%200901Z%20Dec%2013-13%20FINAL%20V3%200.pdf

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Hi,

Are the waypoints not always NDB, VOR's? Or is there something else?

Will just give an example in a few minutes, just searching...

And do the waypoints without radio signals have a name?

Many (though not all) waypoints on RNAV airways are defined in the airspace system solely by their name, and specific latitude/longitude coordinates - without reference to any other navaid.

 

A full RNAV waypoint will appear on a chart as a four-pointed star, with a white circle in the center.

 

Navigating on these routes requires equipment on board the aircraft capable of navigating directly to or from a point defined only by latitude and longitude. In other words, GPS and/or an Intertial Reference System (IRS).

 

Some RNAV waypoints may be VORs or other ground-based navaids, but when flying towards such waypoints on an RNAV route, the navigation system on the aircraft is using the lat/lon coordinates if the VOR, rather than tuning in and flying to it using a VOR receiver.

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1) Do we fly the non RNAV airways with interxepting VOR's Locking them, intercepting NDB's .... Bassically without GPS?

 

2) What is the vertical guidance of an RNAV approach? Does the FMGS knows the vertical profile (kind of a VOR?)

 

Thanks

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Posted Today, 12:41 PM

1) Do we fly the non RNAV airways with interxepting VOR's Locking them, intercepting NDB's .... Bassically without GPS?


2) What is the vertical guidance of an RNAV approach? Does the FMGS knows the vertical profile (kind of a VOR?)

Thanks

 

1) That would depend on how your  aircraft is equipped.  In a GPS or INS equipped system, non-RNAV waypoints can be entered just like any other waypoints.  You will hardly notice the difference.  Some GPS/INS aircraft, such as the 777, don't allow for navigation by following an externally tuned VOR.  You can tune it and set a course, but you either have to navigate by steering , or enter the VOR & radial as a waypoint.  (They do use external nav aids to check against INS errors).  In an aircraft w/out GPS or INS, you would have to tune external nav aids, possibly even steering manually to the intersection of two VOR radials.

 

2)  VNAV does involve the calculation by the aircraft's FMC (flight management computer) of a vertical profile, and takes into account altitude constraints (e.g. "cross JKF VOR at or above 5000, speed 250 or less").  It calculates the proper descent point, or TOD, and if winds  are entered, takes those into account as well.  Also calculates climb, cruise and step-climb profiles.  RNAV approaches use both LNAV (GPS/INS-based Lateral Navigation) and VNAV.  Not sure how that resembles a VOR. 

 

You might want to get a payware addon with advanced navigation capabilities.  PMDG makes several for both FS9 (older) and FSX.  Level-D also makes excellent 767s for both sims.  You can download the Level-D manuals for free from their web site and read the section on navigation using the FMC.

 

Mike

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Thanks, so for an A330-203, does it always use GPS/INS and doesn't use VOR... If yes, why does airbus autotune the VOR and the NDB?

 

2) Has the FMGS the VNAV profile for an A330-203?

 

3) What is the thing with LDA?

 

Thanks

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Thanks, so for an A330-203, does it always use GPS/INS and doesn't use VOR... If yes, why does airbus autotune the VOR and the NDB?

 

2) Has the FMGS the VNAV profile for an A330-203?

 

 

3) What is the thing with LDA?

 

1) Not as familiar with the Airbus but most likely yes.  It tunes external nav aids so the pilot can have backup reference points (especially useful on approaches) and also, I believe it uses the VORs to cross-check & update INS position information automatically. 

 

 

2)  Not sure of your question here -- if the flight management system is in an A330 simulation and it is well done, the answer is yes.  Of course each flight has its own profile, but the computers should be able to calculate it when the flight plan and other information are properly entered.

 

3) That's an  offset approach, where there is a glideslope and localizer that lead you near the runway threshold, but not straight in (so no autoland).  You have to line up just before landing, and in some cases make a low altitude turn.  KDCA 19, one approach for KJFK 22L and the old Kai Tak 13 approaches are examples. If you do a straight-in approach to DCA 19, you fly over the White House, which is prohibited.

 

You should get hold of a good simulation of an advanced jet and do the tutorials.  Not sure what that would be for the A330.  Aerosoft has an A320 the AXE or something like that, that should have a good manual.

 

Mike

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Thanks, so for an A330-203, does it always use GPS/INS and doesn't use VOR... If yes, why does airbus autotune the VOR and the NDB?

Forget about this A330, the answers are the same regardless if it is A330 or a 747 or a Gulfstream G650.

It autotunes because if may want to use VORs too, not only GPS.

You as a pilot should not care how on-board equipment calculates geographical coordinates.

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Ok thanks,

And maybe it can also use it if you would loose the GPS INS/IRS part, no?

Why are the NDB's not autotuned like VOR's

 

Thanks

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Why would you want to autotune NDBs? What for?

They are no use for navigation these days.

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No, for Airbus, it doesn't autotune NDB's,

So if you have lost IRS/INS and GPS, and If your next waypoint is a NDB, how does it do?

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So if you have lost IRS/INS and GPS, and If your next waypoint is a NDB, how does it do?

 

Complete failure of the GPS and INS systems would be a major calamity and extremely unlikely unless there were other major system failures, as I'm sure the A330 has multiple backups for both.  That said, you could still manually tune the NDB if in range, and fly to it using heading hold to steer.  Same for a VOR radial.

 

Mike

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So if you have lost IRS/INS and GPS, and If your next waypoint is a NDB, how does it do?

there are at least two independent GPS receivers and two IRSs so you are saying all 4 go dead?

Nonsense.

And even if this happened why would you care about some NDB? There are so many VORs around unless you are in Africa or Russia?

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Yes, of course it's tough to believe but it means that if it fails, the FMGS will use back up of the VOR, and if you have a NDB you will have to tune it. ADF receivers on Airbus only receives the various signals if you are in a specefied range, and It shows it but doesn't lock it, you have to lock it, right?

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Well, there are actually some AR routes along the US east coast that use NDBs. And I have actually lost the entire GPS capability before, in an E145 at least. It's not out of the question that one might find oneself needing to heading mode their way towards DIW some day.

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!!! michal will be suprised ;)

 

And does an airbus only keeps receiving NDB frequency never locking it? So ADF1 and ADF2 on the RMI will change often, right? ;)

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Well, there are actually some AR routes along the US east coast that use NDBs. And I have actually lost the entire GPS capability before, in an E145 at least. It's not out of the question that one might find oneself needing to heading mode their way towards DIW some day.

 

Yes, and Europe too. It always seems to be American's that have this thing about NDB's.  The world is bigger than just America.... 

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The term 'locking it' is inappropriate here. The ADF receiver is manually tuned the same way you tune your car radio to a music station. As far as I know, no system autotunes ndb frequencies, so the rmi needles will just point to whatever stations you have tuned in.

 

If you completely lose all rnav capability to the point where all you have left is basic manual radio navigation, you simply advise ATC of your predicament and they will vector you as needed and reclear you on a route that you can navigate on with what's left. It is really a non-issue.

Yes, and Europe too. It always seems to be American's that have this thing about NDB's. The world is bigger than just America....

Well, that's because there are few left here and it is clearly the FAA's intent to decommission all of them eventually.

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Seems to me if you lost GPS & INS capability, you would not want to rely on the autotune function for VORs (if it were still working -- I think this function needs working GPS or INS to be able to select nearby VORs).  You would want to tune each VOR manually, which you certainly can do.

 

Mike

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Posted Today, 12:33 PM
Check this: http://www.aer.ita.b...320/fwd/nd1.jpg

1) Has he lost FMGS, and is he using the 3 RMP?
2) What does M mean? manually?

 

1) He has not lost the FMGS, as TILLE is probably an RNAV waypoint.  However I can't find it in a recent FS Commander database or on Airnav.com so I think this is an old picture. 

2) Probably M = manually tuned.  Pilot has tuned AML, a VOR on the Dulles airport next to runway 30 and an NDB named IA (also can't find that in recent databases).  It makes sense to manually tune a VOR at the airport as it provides a good check on the aircraft's position in relation to it and distance from it.  You wouldn't want to have it on autotune as it might choose a VOR that is less useful. 

 

3) Don't know. 

 

Looks to me that the aircraft is on an ILS approach but too far out (45NM) to detect the ILS. Having AML tuned is especially useful here since ILS/DME information is not yet available.  The ILS approach chart for this runway shows that an early waypoint in the approach, DECES, lies on AML radial 182 and is 30 NM from AML, as a check on GPS/INS navigation.  DECES is presumably an RNAV waypoint, but its location can also be determined by finding the intersection of two radials, the AML 182 radial and the BRV (BROOKE) 347 radial (at 6.5 NM).

 

http://flightaware.com/resources/airport/IAD/IAP/ILS+RWY+01R+%28CAT+II+-+III%29/pdf

 

Also something odd about the nav display picture: AML is not far out from the airport as the circle marked AML would suggest.  But I'm not very familiar with Airbus displays (which I assume this is).

 

Mike

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