Why "best" VOR-DME is never indicated on RNAV APP charts?


ILS APP charts clearly show ILS course and frequency, VOR/DME/LOC/ecc when needed and it is quite useless because clearly indicated by my CDU APP page (B738).
I often choose to land using RNAV/RNP when the weather permits but never saw indications about VOR/DME/LOC.
It’s not a problem because I can easily find the one that best fits with AivlaSoft EFB.

But my question remains: Why “best” VOR-DME is never indicated on RNAV APP charts?

Best regards and best wishes for 2023,


Probably because it’s neither required nor applicable.

Conventional approaches are designed with and meant to be flown using radio navaids and magnetic course/radials; even though an airliner’s FMS is capable to fly some of it on its own, the approach will not be available for use if the required navaid(s) are INOP.

RNAV apporoaches, on the other hand, do not require nor make use of radio navaids.



Hello Tim,

I imagine you are speaking of the “modern” RNAV(GPS) that is essentially based on GPS or GNSS.
“Our” ProSim Boeing 737 are not GNSS capable.

Considering this article “terminology - What is the difference between GPS, GNSS and RNAV? - Aviation Stack Exchange”, when asking my question I had in mind the last paragraph (that applies to our RNP and IAN approaches): In the “old days”, it was possible to have RNAV operations that worked by taking radial/DME data…

Best regards,


Even without GNSS, your 737 can still likely do RNAV with a combination of multiple IRS systems and DME/DME updating (as opposed to whatever is described in the last paragraph re: old days). The first paragraph should still be applicable:

RNAV is the aircraft capability that allows you to navigate from point to point, defined by Latitude/Longitude and independent of any ground-based system. There are various ways that the hardware in the aircraft maintains its position. It may use GPS sensors, it may use GLONASS, it may uses a combination of satellite systems, it may use DME/DME updates from ground-based navaids. But the point of RNAV is that for the most part the procedures are agnostic with regard to how the position info is obtained.

(emphasis added on that last statement)

Obviously, for a non-GNSS aircraft you would indeed want to tune the “best” navaid(s) to make DME/DME updating as accurate as possible, but presumably this information is outside the scope of the approach chart specifically.

However, I do get the point of your question now, and I cannot explain the “why” nor do I have an idea of which chart(s) real-world pilots would reference to pick the navaids for that purpose. Someone else may be able to chime in.



Hello Tim,

Again, thank you for your answer. I totally agree with you :slight_smile:

I need to investigate further (I must “confess” my ProSim have already correctly flown an RNAV approach without radio set or with VOR/ADF switches set to “OFF” :worried:):

In fact my question came because my “colleagues” (who do not run AivlaSoft) ask me “What is the VOR/DME frequency?”. I used to tell them “Give a look to the ILS chart” as it seemed to me the VOR/DME frequency was “always” indicated there. But recently my theory failed, and more than once.

EDIT (from a non official source):