DME/DME RNP-0.3 NA

If you don't know what to do with it, the answer to what you do with it is "nothing". RNP approaches require special certification for aircraft and training for the crew. If you'd had that training, you'd know what this means. Since you don't, you haven't, and you're not flying RNP approaches, so it doesn't affect anything you do.

That said, it means if the RNP system you're using to fly RNP approaches is based on DME/DME with RNP-0.3 accuracy, you can't use that system to fly this particular RNP approach even though you can normally use a DME/DME-0.3 RNP system to fly RNP approaches.
 
ah thanks. Trying to grasp all the details at any airport my check ride may include and noticed this. Now I want to learn more about it.
 
JasonM said:
What does this mean?

Look at the RNAV 23 @ EKN. It says "Circling NA at Night. DME/DME RNP-0.3 NA. Visibility reduction by helicopters NA.... etc. etc..

What is this and what do I do with this information?:
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That was my DPE's "stump the dummy" question for me on my IR checkride. I offered that it doesn't apply to me, and he was satisfied with that and then used it as a teaching moment. Basically, what he told me is what C'Ron said.
 
Ron Levy said:
If you don't know what to do with it, the answer to what you do with it is "nothing". RNP approaches require special certification for aircraft and training for the crew. If you'd had that training, you'd know what this means. Since you don't, you haven't, and you're not flying RNP approaches, so it doesn't affect anything you do.

That said, it means if the RNP system you're using to fly RNP approaches is based on DME/DME with RNP-0.3 accuracy, you can't use that system to fly this particular RNP approach even though you can normally use a DME/DME-0.3 RNP system to fly RNP approaches.
Click to expand...

I don't know of any RNAV approach that permits use of DME/DME 0.30, do you?

And, certainly RNP AR does not permit it. It requires two GPS receivers, and a whole lot of other redundancy. Light airplane GA will never be able to fly RNP AR.

Advanced RNAV is coming along one of these days, though, which some light airplanes will be able to fly, once the feds can agree on the ground rules for flying RF legs for non-RNP AR aircraft.
 
JasonM said:
What does this mean?

Look at the RNAV 23 @ EKN. It says "Circling NA at Night. DME/DME RNP-0.3 NA. Visibility reduction by helicopters NA.... etc. etc..

What is this and what do I do with this information?: DME/DME RNP-0.3 NA

https://www.fltplan.com/AwDisplayAppChart.exe?CRN10=1&CARRYUNAME=PILOT&DEPTARPT=KEKN&ARRARPT=XPTG&TYPECHART=00128R23.PDF&END=END&WINDOW=YES
Click to expand...

DME/DME is a technology that mostly airliners and some corporate aircraft have installed that permits them to navigate using RNAV routes. It is based on a FMS (Flight Management System) that receives multiple DME stations to triangulate the aircraft position. The DME frequencies, locations and identifiers are stored in the FMS database and are used to make the position determination. It only works where there are sufficient DME locations in order to determine a fix, such as over land. In the case of RNAV (GPS) approaches, there are rarely sufficient DME's in the immediate area to be able to maintain a valid position. DME/DME RNP 0.3 is a statement of a Navigation specification that requires a position to be determined within +/- 0.3 NM. An RNAV (GPS) approach with LNAV lateral is technically an RNP 0.3 approach in ICAO terminology.
 
Ron Levy said:
If you don't know what to do with it, the answer to what you do with it is "nothing". RNP approaches require special certification for aircraft and training for the crew. If you'd had that training, you'd know what this means. Since you don't, you haven't, and you're not flying RNP approaches, so it doesn't affect anything you do.

That said, it means if the RNP system you're using to fly RNP approaches is based on DME/DME with RNP-0.3 accuracy, you can't use that system to fly this particular RNP approach even though you can normally use a DME/DME-0.3 RNP system to fly RNP approaches.
Click to expand...

In ICAO terminology, an RNAV (GPS) approach is RNP 0.3, see AC 90-105. You are thinking of RNAV (RNP) which require authorization.
 
aterpster said:
I don't know of any RNAV approach that permits use of DME/DME 0.30, do you?

And, certainly RNP AR does not permit it. It requires two GPS receivers, and a whole lot of other redundancy. Light airplane GA will never be able to fly RNP AR.

Advanced RNAV is coming along one of these days, though, which some light airplanes will be able to fly, once the feds can agree on the ground rules for flying RF legs for non-RNP AR aircraft.
Click to expand...
I assumed without looking that the approach which the OP was discussing was an RNAV(RNP) approach, and now that I look further, it isn't. As an RNAV(GPS) approach, Wally is correct -- you must be using GPS as the primary sensor on the final segment, so I can't imagine why that note is there.

Of course, the answer about what that Note means to the OP is still "nothing", since the OP almost certainly isn't flying an RNP aircraft with DME/DME-0.3 capability.
 
John Collins said:
DME/DME is a technology that mostly airliners and some corporate aircraft have installed that permits them to navigate using RNAV routes. It is based on a FMS (Flight Management System) that receives multiple DME stations to triangulate the aircraft position. The DME frequencies, locations and identifiers are stored in the FMS database and are used to make the position determination. It only works where there are sufficient DME locations in order to determine a fix, such as over land. In the case of RNAV (GPS) approaches, there are rarely sufficient DME's in the immediate area to be able to maintain a valid position. DME/DME RNP 0.3 is a statement of a Navigation specification that requires a position to be determined within +/- 0.3 NM. An RNAV (GPS) approach with LNAV lateral is technically an RNP 0.3 approach in ICAO terminology.
Click to expand...
However, unless I'm missing something, one is not authorized to use DME/DME RNP to sub for GPS on an RNAV(GPS) approach, since it doesn't say anything but "GPS" in the title.
 
Ron Levy said:
However, unless I'm missing something, one is not authorized to use DME/DME RNP to sub for GPS on an RNAV(GPS) approach, since it doesn't say anything but "GPS" in the title.
Click to expand...

The last part of the statement is not strictly true, as any navigation system that meets the RNP 0.3 criteria in theory could fly the procedure, but I am not aware of any such example.

This is from AC 90-105:

This Appendix provides guidance on the performance and functional requirements for systems used to conduct Required Navigation Performance (RNP) approach operations, which are designated under Title 14 of the Code of Federal Regulations (14 CFR) part 97 as Area Navigation (RNAV) Global Positioning System (GPS) or GPS and categorized as RNP Approach (APCH) by the International Civil Aviation Organization (ICAO).
Click to expand...

In a note, they go on to say in the AC:

NOTE: DME/DME or DME/DME/IRU as the only means of RNP compliance are not authorized to conduct RNP approaches. However, operators still retain the option to develop Special RNP approaches using these systems.
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This is from the Jeppesen description:

An RNP level or type is applicable to a selected airspace, route, or procedure. The applicable RNP is expressed as a value that represents a distance in nautical miles from the intended position to the actual position of an aircraft. It is within this distance that an aircraft would normally be expected to operate. For general RNAV approach procedures, RNP-0.3 is required.

Aircraft meeting RNP criteria will have an appropriate entry, including special conditions and limitations, if any, in the Aircraft Flight Manual (AFM) or itssupplement. This will only occur when it has been determined that the aircraft complies with the appropriate provisions of certification.

Some aircraft have RNP approval in their AFM without a GPS sensor. The
lowest level of sensors that the FAA will support for RNP service is DME/DME. However, necessary DME NAVAID ground infrastructure may or may not be available at the airport of intended operations. For those locations having an RNAV chart published with LNAV/VNAV minimums, a procedure note may be provided such as “DME/DME RNP-0.3 NA”; this means that RNP aircraft dependent on DME/DME to achieve RNP-0.3 are not authorized to conduct this approach. Where FAA flight inspection successfully determines the availability and geometry of DME facilities will support RNP-0.3 and that the DME signal meets inspection tolerances, a note such as "DME/DME RNP-0.3 Authorized” will appear on the chart. And where DME facility availability is a factor, the note may read “DME/DME RNP-0.3 Authorized; ABC and XYZ Required”; meaning that ABC and XYZ facilities have been determined by flight inspection to be required in the navigation solution to assure RNP-0.3.
Click to expand...

Regardless, I agree that it doesn't apply to the OP and he can ignore the note.
 
John Collins said:
DME/DME is a technology that mostly airliners and some corporate aircraft have installed that permits them to navigate using RNAV routes. It is based on a FMS (Flight Management System) that receives multiple DME stations to triangulate the aircraft position. The DME frequencies, locations and identifiers are stored in the FMS database and are used to make the position determination. It only works where there are sufficient DME locations in order to determine a fix, such as over land. In the case of RNAV (GPS) approaches, there are rarely sufficient DME's in the immediate area to be able to maintain a valid position. DME/DME RNP 0.3 is a statement of a Navigation specification that requires a position to be determined within +/- 0.3 NM. An RNAV (GPS) approach with LNAV lateral is technically an RNP 0.3 approach in ICAO terminology.
Click to expand...

The first few years after GPS became operational a few carriers that did not have GPS, but had DME/DME/IRU RNAV were authorized to fly GPS approaches. One airline had such a significant map shift on approach in your next of the woods, they came close to hitting a tower 1 mile, or so, off to the side. This event ended DME/DME for approaches.

Thus, the note, because there are still some of those old pre-GPS FMSes flying around.
 
John Collins said:
Some aircraft have RNP approval in their AFM without a GPS sensor. The lowest level of sensors that the FAA will support for RNP service is DME/DME. However, necessary DME NAVAID ground infrastructure may or may not be available at the airport of intended operations. For those locations having an RNAV chart published with LNAV/VNAV minimums, a procedure note may be provided such as “DME/DME RNP-0.3 NA”; this means that RNP aircraft dependent on DME/DME to achieve RNP-0.3 are not authorized to conduct this approach. Where FAA flight inspection successfully determines the availability and geometry of DME facilities will support RNP-0.3 and that the DME signal meets inspection tolerances, a note such as "DME/DME RNP-0.3 Authorized” will appear on the chart. And where DME facility availability is a factor, the note may read “DME/DME RNP-0.3 Authorized; ABC and XYZ Required”; meaning that ABC and XYZ facilities have been determined by flight inspection to be required in the navigation solution to assure RNP-0.3.
Click to expand...
Click to expand...
That's the part I didn't know -- that it was possible to have approval to fly an approach without the equipment specified for lateral guidance on the final segment (in this case, DME/DME subbing for GPS). Thanks for pointing it out.
 
Ron Levy said:
That's the part I didn't know -- that it was possible to have approval to fly an approach without the equipment specified for lateral guidance on the final segment (in this case, DME/DME subbing for GPS). Thanks for pointing it out.
Click to expand...

If you find one, let me know. I'd like to see one.
 
Here is how I parse 'DME/DME RNP-0.3 NA', please correct me if I'm wrong:

'DME/DME' refers to flight management systems that derive position from two different DME stations, as discussed above.

RPN-0.3 refers to a 'Required Navigation Performance' device that is accurate to +/- 0.3 to 1.0nm along a route.

NA means 'not authorized'

So if you bought an old Learjet for $600K it might have an RNP 0.3 DME/DME flight management systems, but no GPS. If so you can't fly this approach.

Now if you just bought a G650 for $650M that has an RPN 0.1 nav system and GPS is notam'd out, maybe you could fly this. I'll leave that discussion to the Gulfstream pilots and hanger lawyers.
 
JimNtexas said:
Here is how I parse 'DME/DME RNP-0.3 NA', please correct me if I'm wrong:

'DME/DME' refers to flight management systems that derive position from two different DME stations, as discussed above.

RPN-0.3 refers to a 'Required Navigation Performance' device that is accurate to +/- 0.3 to 1.0nm along a route.

NA means 'not authorized'

So if you bought an old Learjet for $600K it might have an RNP 0.3 DME/DME flight management systems, but no GPS. If so you can't fly this approach.

Now if you just bought a G650 for $650M that has an RPN 0.1 nav system and GPS is notam'd out, maybe you could fly this. I'll leave that discussion to the Gulfstream pilots and hanger lawyers.
Click to expand...

You got most of it.

The fact the G650 can do RNP 0.10 works only if GPS is working. So, if GPS is notam'd OTS, the G650 crew will have to shop for an LNAV approach with DME/DME 0.30 authorized. I think they will run out of gas first. :wink2:
 
JimNtexas said:
RPN-0.3 refers to a 'Required Navigation Performance' device that is accurate to +/- 0.3 to 1.0nm along a route.
Click to expand...

RNP 0.3 specification means that the navigation equipment meets the accuracy performance of +/- 0.3 NM 95 percent of the time and incorporates associated on-board performance monitoring and alerting features to notify the pilot when the RNP specification is not being met.
 
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