Rnav navigation

[Mike777 163]

 

 

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

[michal 44]

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?

[AF330 0]

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?

[KevinAu 441]

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.

[AF330 0]

!!! 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?

[FLEX1978 373]

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.... 

[KevinAu 441]

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.

[AF330 0]

Check this: http://www.aer.ita.br/~bmattos/mundo/320/fwd/nd1.jpg

 

1) Has he lost FMGS, and is he using the 3 RMP?

2) What does M mean? manually?

3) What is written for VOR's if they are autotuned?

[Mike777 163]

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

[Mike777 163]

 

 

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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

[AF330 0]

Thanks 

1) But why has he tuned the NDB?

2) I can still understand the VOR, but if he has tuned manually an NDB, does it follow it or does it only follow it when you turn off A/P?

3) So, if you have lost both FMGS, and if you tune 2 VOR's, and enter the CRS, which one will it follow?

The VOR 1 first and then the VOR 2?

 

Thanks,

[michal 44]

Also something odd about the nav display picture

 

Yeah, it is also strange how the AML VOR symbol is depicted, there is normally a standard symbol for VORs that everyone is familiar with, here it looks like an airport on enroute charts. And like you said, AML should practically overlap with the airport. Strange, unless it is some Airbus idiosyncrasy or error in simulation.

[KevinAu 441]

Thanks

1) But why has he tuned the NDB?

2) I can still understand the VOR, but if he has tuned manually an NDB, does it follow it or does it only follow it when you turn off A/P?

3) So, if you have lost both FMGS, and if you tune 2 VOR's, and enter the CRS, which one will it follow?

The VOR 1 first and then the VOR 2?

 

Thanks,

1. Why not? The Nav 1 side can still be tuned to a vor or ils. It is merely the left rmi has been selected to display the adf. If nav1 has an ils tuned, the rmi wouldn't work with it anyways, so you can switch that display to adf.

 

2-3. Airbus and Boeing nav modes do not track vor or ndb signals. If you have to navigate on raw vor or ndb's then you use the heading knob to manually fly the plane left or right to follow the desired course.

[AF330 0]

I just don't get this:

Why does it tune each and every VOR?  For the RMI IF WE LOSE FMGS?

 

Thanks a lot!

[KevinAu 441]

I just don't get this:

Why does it tune each and every VOR? For the RMI IF WE LOSE FMGS?

 

Thanks a lot!

I don't get your question.