And away goes VOR/DME RNAV...

denverpilot

denverpilot

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DenverPilot
From: https://www.faa.gov/training_testing/testing/media/whats_new_general.pdf

"Changes Applicable to the Instrument Rating Airplane (IRA) Knowledge Test • The following subject(s) have been removed: o VOR/DME RNAV

Changes Applicable to the Airline Transport Pilot Multiengine (ATM) and Aircraft Dispatcher (ADX) Knowledge Tests • The following subject(s) have been removed: o VOR/DME RNAV"

Coming this summer to a written test near you!
 
denverpilot said:
From: https://www.faa.gov/training_testing/testing/media/whats_new_general.pdf

"Changes Applicable to the Instrument Rating Airplane (IRA) Knowledge Test • The following subject(s) have been removed: o VOR/DME RNAV

Changes Applicable to the Airline Transport Pilot Multiengine (ATM) and Aircraft Dispatcher (ADX) Knowledge Tests • The following subject(s) have been removed: o VOR/DME RNAV"

Coming this summer to a written test near you!
Click to expand...

Wonder if they're planning on just getting rid of it. Hopefully they'll get DME/DME RNP 0.3 NA out of the remarks boxes on charts. Some of those things are seriously cluttered.
 
luvflyin said:
Wonder if they're planning on just getting rid of it. Hopefully they'll get DME/DME RNP 0.3 NA out of the remarks boxes on charts. Some of those things are seriously cluttered.
Click to expand...
DME/DME RNP 3.0 is something entirely different.
 
I wonder if those will be gone on the Flight Test? I have RNAV in my plane (KNS80) that I never used, an don't know how to, except its VOR and DME.
 
Cruzinchris said:
I wonder if those will be gone on the Flight Test? I have RNAV in my plane (KNS80) that I never used, an don't know how to, except its VOR and DME.
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KNS80 is easy, it is Roe-theta navigation. And nice to have the DME hold function.

ILS on one freq, but requires the DME on different freq. tune the DME, select DME hold, then tune the ILS.
Works great.

Want to go direct to an intersection from off airway. Tune the freq, rad, dist and select it as active. CDI is left right nav to the intersection, with DME to it.
 
luvflyin said:
whats the difference?
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Like @BillTIZ said, VOR/DME RNAV is rho-theta navigation...a VOR, radial (the "rho" part), and distance (the "theta" part) to build a waypoint for navigation. The KNS-80 and KNS-81 (and KN-74, for us old guys) were the mainstays of that form of navigation, and there used to be RNAV approaches that specified rho-theta waypoints to build and fly.

DME/DME RNP .3 is when a system uses three DME stations to triangulate a position, and that system is certified to the same .3 mile scale as GPS approach precision. My understanding is that the reason these approaches are not authorized for DME/DME RNP .3 is that by the time you get to MDA, you're not in range of enough DME stations to establish a position.
 
luvflyin said:
whats the difference?
Click to expand...
DME/DME/IRU is an Flight Management System (FMS) that uses Inertial Reference Units (IRU) with position updating from DME/DME. These systems can produce an Actual Navigation Performance (ANP) of 0.30 (for Required Navigation Performance (RNP) 0.30 procedures), with the proper DME availability and geometry, but not all RNP 0.30 procedure allow them. Those RNP 0.30, and lower, procedures require GPS updating to the FMS.

The B767s that I flew, at a previous employer, were DME/DME/IRU as they had no GPS position updating.
 
@Larry in TN , @MauleSkinner , @BillTIZ . I just figured the original RNAV, before when RNAV became the 'umbrella' term for everything, was all pretty much the same thing. So if it says DME/DME RNP 0.3 not authorized it means that 'specifically,'. You could do the Approach with a rho-theta unit or some other RNAV as long as it isn't specifically a DME/DME one?????
 
denverpilot said:
From: https://www.faa.gov/training_testing/testing/media/whats_new_general.pdf

"Changes Applicable to the Instrument Rating Airplane (IRA) Knowledge Test • The following subject(s) have been removed: o VOR/DME RNAV

Changes Applicable to the Airline Transport Pilot Multiengine (ATM) and Aircraft Dispatcher (ADX) Knowledge Tests • The following subject(s) have been removed: o VOR/DME RNAV"

Coming this summer to a written test near you!
Click to expand...

Considering the last VOR/DME RNAV approach in the U.S. was cancelled last September (if I remember right), I'd say this is a prudent move.
 
luvflyin said:
@Larry in TN , @MauleSkinner , @BillTIZ . I just figured the original RNAV, before when RNAV became the 'umbrella' term for everything, was all pretty much the same thing. So if it says DME/DME RNP 0.3 not authorized it means that 'specifically,'. You could do the Approach with a rho-theta unit or some other RNAV as long as it isn't specifically a DME/DME one?????
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No...there's no waypoint information for tho-theta RNAV on the approach plate, And it's assumed that you know GPSapproach waypoints have to be in a procedure in the database. Also, an RNAV(GPS) approach specifies that GPS is used.

Think of it this way...DME/DME is a position sensor, much like GPS. In fact, it uses the same type of algorithm as GPS to determine position, except that it measures distance from DME stations instead of satellites. Many FMS systems still use DME/DME as a position sensor in addition to GPS.

When you build a waypoint in your GPS with a radial and distance, that's exactly what tho-theta RNAV is all about, except that you used a special VOR box instead of a GPS box. Back in the old days, the FAA built approaches that specifically required us to build the approach waypoints. Non-modifiable approach waypoints was a new spec for GPS approaches. That's what the FAA has removed from the written test.
 
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Narco was first with the CLC-60 "Course Line Computer," in 1968. Jeppesen sold special "RNAV" enroute charts that made navigation a snap.

We kept a little notebook of the waypoints on the routes we used, and programmed them into a King Gold Crown KNR 665.

clc.jpg
 
kgruber said:
Narco was first with the CLC-60 "Course Line Computer," in 1968. Jeppesen sold special "RNAV" enroute charts that made navigation a snap.

We kept a little notebook of the waypoints on the routes we used, and programmed them into a King Gold Crown KNR 665.

clc.jpg
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I've seen the Narco one, now that you mention it.

Back in the '80s, the state of Minnesota put weather computers at public airports that would also build a flight plan with RNAV waypoints every 50 or 100 miles. Easy peasy!

The KN-74 is the only one I've actually shot an approach with...I remember thinking something along the lines of, "man, there's a lot of potential for error building these waypoints in the middle of an approach."

Never crashed, tho, so it musta' been safe! ;)
 
luvflyin said:
@Larry in TN , @MauleSkinner , @BillTIZ . I just figured the original RNAV, before when RNAV became the 'umbrella' term for everything, was all pretty much the same thing. So if it says DME/DME RNP 0.3 not authorized it means that 'specifically,'. You could do the Approach with a rho-theta unit or some other RNAV as long as it isn't specifically a DME/DME one?????
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RNAV has ALWAYS been an umbrella term for all types of area navigation. It is only in the G.A. community where course-line computers (CLC) were assumed to be the only RNAV because they were the only RNAV units that were seen for G.A. aircraft in the 1970s and much of the 1980s.

CLC RNAV systems could, at one time, do RNAV approaches but only RNAV approaches that were specifically designed for CLC RNAV. As someone else has mentioned, they no longer exist.

Anything you see now referring to non-GPS RNAV systems will be flight management systems using inertial reference and DME/DME updating. What those notes mean is even if the non-GPS FMS can produce an ANP of 0.30 it still can not be used for procedures which excelude DME/DME/IRU-0.30.

FMS systems with GPS position updating, in addition to DME/DME updating, are now doing RNP and GLS approaches. The 737s I fly can do RNP approaches down to RNP 0.11. I don't think I've seen any approaches with published minimums below RNP 0.10 but there may be some. I've also flown GLS approaches at EWR and IAH--the first two US airports with GLS approaches. They are a form of local area augmentation and require a GLS ground station to achieve CAT I landing minimums. The intent to is eventually expand GLS to CAT II/III with autoland.

The 767s I used to fly for another employer did not have the GPS updating so we were restricted to procedures that permitted DME/DME/IRU ops.
 
Larry in TN said:
I don't think I've seen any approaches with published minimums below RNP 0.10 but there may be some.
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There are none that I know of, at least in the U.S.

Minimum RNP NavSpec in FAAO 8260.58A (the design criteria for RNAV (GPS) and RNAV (RNP) approaches) is 0.1.
 
RussR said:
Minimum RNP NavSpec in FAAO 8260.58A (the design criteria for RNAV (GPS) and RNAV (RNP) approaches) is 0.1.
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The 737NG is certified for RNP 0.11. I've flown many approaches that have RNP 0.11 minimums. I've also seen approaches with RNP 0.10 minimums.

Do you have any idea what the difference is between 0.11 and 0.10? I wonder what the 737NG lacks that precludes the additional 0.01?
 
Larry in TN said:
RNAV has ALWAYS been an umbrella term for all types of area navigation. It is only in the G.A. community where course-line computers (CLC) were assumed to be the only RNAV because they were the only RNAV units that were seen for G.A. aircraft in the 1970s and much of the 1980s.

CLC RNAV systems could, at one time, do RNAV approaches but only RNAV approaches that were specifically designed for CLC RNAV. As someone else has mentioned, they no longer exist.

Anything you see now referring to non-GPS RNAV systems will be flight management systems using inertial reference and DME/DME updating. What those notes mean is even if the non-GPS FMS can produce an ANP of 0.30 it still can not be used for procedures which excelude DME/DME/IRU-0.30.

FMS systems with GPS position updating, in addition to DME/DME updating, are now doing RNP and GLS approaches. The 737s I fly can do RNP approaches down to RNP 0.11. I don't think I've seen any approaches with published minimums below RNP 0.10 but there may be some. I've also flown GLS approaches at EWR and IAH--the first two US airports with GLS approaches. They are a form of local area augmentation and require a GLS ground station to achieve CAT I landing minimums. The intent to is eventually expand GLS to CAT II/III with autoland.

The 767s I used to fly for another employer did not have the GPS updating so we were restricted to procedures that permitted DME/DME/IRU ops.
Click to expand...

By "I just figured the original RNAV, before when RNAV became the 'umbrella' term for everything" I was thinking of when a few years all 'non conventional' approaches were 'named' RNAV. GPS Approaches became RNAV(GPS) etc. I see now that there's a lot more to it than just that.
 
Historically speaking, with curved glide path capability and variable descent angles and what not, would y’all say MLS was an early “RNAV” system as well?
 
denverpilot said:
Historically speaking, with curved glide path capability and variable descent angles and what not, would y’all say MLS was an early “RNAV” system as well?
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I never flew anything MLS equipped but my understanding is that it a ground-based approach like an ILS but with different capabilities. It's not area navigation (RNAV).
 
Larry in TN said:
I never flew anything MLS equipped but my understanding is that it a ground-based approach like an ILS but with different capabilities. It's not area navigation (RNAV).
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Agreed but it did work over a very small “area” according to all I’ve read about it. :)
 
denverpilot said:
Agreed but it did work over a very small “area” according to all I’ve read about it. :)
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Again, I never used an MLS, but I don't think it met the definition of RNAV (from 14 CFR 1.1) as it didn't let you choose a random flight path. The curved paths were predefined.

14 CFR 1.1 - Area navigation (RNAV) is a method of navigation that permits aircraft operations on any desired flight path.
 
Larry in TN said:
Again, I never used an MLS, but I don't think it met the definition of RNAV (from 14 CFR 1.1) as it didn't let you choose a random flight path. The curved paths were predefined.

14 CFR 1.1 - Area navigation (RNAV) is a method of navigation that permits aircraft operations on any desired flight path.
Click to expand...

I believe the on board system allowed section of that curved flight path. It was that the approach wasn’t certified if you didn’t select the stuff on the plate, that made the path “defined”.

It’s just an interesting side point really. Long dead. Rocky Mtn Airways was using them to get into mountain airports and promoting them heavily, as a benefit over their arch rival, Aspen Airways, but now even most of those airports are long gone along with both companies.
 
kgruber said:
The other "curved path" approach was the transponder landing system. They had a demo set up at Madras Airport.

https://en.wikipedia.org/wiki/Transponder_landing_system
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They had one of those set up at Watertown, WI KRYV as well. When I first found out about TLS, and then found out there was one at Watertown, you still had to ask the FBO for the plate, it wasn't in the books. So I asked about it, and found out it had been decommissioned a couple months before. Oh well, would have been cool to fly one!
 
MauleSkinner said:
Like @BillTIZ said, VOR/DME RNAV is rho-theta navigation...a VOR, radial (the "rho" part), and distance (the "theta" part) to build a waypoint for navigation. The KNS-80 and KNS-81 (and KN-74, for us old guys) were the mainstays of that form of navigation, and there used to be RNAV approaches that specified rho-theta waypoints to build and fly.

DME/DME RNP .3 is when a system uses three DME stations to triangulate a position, and that system is certified to the same .3 mile scale as GPS approach precision. My understanding is that the reason these approaches are not authorized for DME/DME RNP .3 is that by the time you get to MDA, you're not in range of enough DME stations to establish a position.
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You have it backwards- Rho is a distance from the DME and Theta is an angle. Theta is relative to the facility magnetic north.
 
denverpilot said:
Agreed but it did work over a very small “area” according to all I’ve read about it. :)
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Correct- MLS was intended for terminal use, not enroute. MLS had three systems: AZ/EL/DME. AZ was the analog to the Localizer/LLZ, EL was the analog to Glide Slope (GS) and DME was actually a P(recision)DME with improved accuracy over a typical LOC/DME. The AZ and EL antennas were planar phased arrays which set up a time scanning beam which allowed the aircraft to determine a precise position in a polar coordinate system. The AZ and EL antennas were directional and only intended to be used on the approach.
 
just to add a smidge more triva wrt MLS. The AZ and EL guidance was directional (no pun) via a scanned beam, the data portion of the AZ and EL functions was (more or less) omni directional within the coverage volume.
 
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