I have not been able to find an answer to this in the manuals, nor on the Internet.

 

On the NAV/RAD page of the CDU, the frequencies are shown with a letter next to them.  "A" means the frequency is auto-tuned.  "M" means the frequency is manually tuned.  But what does "R" mean?  I am guessing that perhaps it might mean this frequency is in the flight plan 'R'oute?

 

Can anyone enlighten me please?

Exactly: 'R' like ... p'R'ocedural autotuning.

 

Wrong: It's in the manuals.  

Thanks for the reply.  p'R'ocedural.  I see.

 

The only reference I can find in the manuals is in the FMC USER'S MANUAL on page 14, where it says:

 

"A small ‘A’ next to a frequency indicates that the station has been auto-tuned for navigation verification. An ‘M’ indicates that the frequency is manually selected by the crew. Station identifier information appears in the center of the display, along with current redial TO the selected station."

 

But I note that this makes no mention of the "R".  I've used the "find" feature of my PDF reader software, and gone through all of the manuals from 01 to 13 ... but I cannot locate any other reference(s) to this.  Then again, to get search results, one must enter good search word(s) in to the search field so that the information can be found.  Considering I've been "guessing" search terms in the hope I might get a hit, it hasn't helped.  If there are indeed more references in the manuals, I haven't been able to locate them. 

 

 

Thanks to your response, I used the search term "procedural autotune" in Google, and came across this:

 

----------------------------

 

• P (procedure autotuning) – FMC selects navaids for approach or departure procedure guidance

• R (route autotuning) – FMC selects navaids on the active route. The navaid is the previous VOR or a downpath VOR within 250nm of aircraft position

• A (autotuning) – FMC selects a navaid for best position orientation

• M (manual) – VOR is manual–tuned. Manual–tuning takes priority over FMC autotuning. Deletion of a manual–tuned frequency returns system to autotuning.

 

----------------------------

 

Excellent.

 

Thanks Oliver.  Your "prompting" got me to the answer.

 

One continues to learn ... every day. 

Couldn't retrieve it myself from the PMDG pdf ...

 

Might have been either in the printed manual included in the German Aerosoft box (I own the FSX version as a download version only, but the FS9 one boxed).

 

Or I might have read it in the B777 documentation, as the T7 autotunes as well. (Must have been the PSS product, then.)

Ahh.  I've been looking in the supplied PDF manuals from the PMDG boxed version.  But, it probably doesn't matter anymore now that I've found the answer in Google thanks to your prompting.

 

(I think you and I might have been posting at the same time.  I was editing my post above to add more stuff, and I think you might have been subsequently responding at the same time.  So you might not have seen the part I added to my post at the end which I copied/pasted from Google and confirms 'P'rocedural autotuning as well as 'R'oute autotuning).

 

Thanks once more.