FSX: FMC Nav Invalid errors

[Guest 413X3]

I never got this in FS9. I am flying to a few airports, ZSPD, and EDDF. I have the latest navdata, but when I arm the LOC, then APR it says "nav invalid"Why cant it arm the cat3 landing? I am landing on runways with correct localisers. I have checked them in AFX

[downscc 1,327]

Please sign you name in this forum.You could have provided a little more info to make this easier to figure out; however, comparing the navdata with the stock FSX navaid data reveals that FSX has the wrong ILS freq for 07L.There should be a clue that this is the problem, since the LOC freq will be displayed on the PFD as not available. From memory, I think it is displayed in yellow with a line through it.The quick fix is to manually enter the "incorrect" freq from the FSX Map info. You can also update the stock bgl file with AFX, or install a current scenery, which would allow the use of automated tuning based on current navdata.This is a typical problem with Microslop.

[Guest 413X3]

But none of that would explain why the fmc said invalid... if it was not a correct freq then i just wouldn't get anything up on the display. But the FMC should at least tune that freq. i select ILS 7L in the approach section of the nav page, so why doesn't it put a correct freq in there?If it isn't in the afcad the FMC doesn't know that, if it wasn't in the afcad or fsx file then it just wouldn't tune the correct freq, right?-Alex

[downscc 1,327]

The FMC is tuning to the freq provided by wpNavAPT.txt in navdata for ILS 7L, but FSX has a different freq so the nav receiver is not receiving anything, as you said. Try manually entering the old frequency used by FSX and let us know if that works.I don't know why you got an invalid message.

[beefix 2]

Now that's really strange I've just had a similar problem with FS9. Last night I did a short flight from EGJJ (Jersey) to EGCN (Doncaster)using the 737-700. I planned to do an ILS approach to runway 02. I tuned to the all the correct frequencies (110.95)the FMC also displayed all the correct information. However,the aicraft did not capture the ILS and I then got an FMC message saying "NAV INVALID". I've looked at the AFCAD and that seems to be OK. So what went wrong?RgdsSteve Honey

[downscc 1,327]

Do you mean the FMC had 110.95/course on the APPR INIT page? That and the freq/crse displayed on the PFD are the only places that the navdata for ILS show up in the 737; otherwise, it is strictly manual.If the navdata matches MSFS then the NAV INVALID message is a mystery and maybe some screen shots might help figure it out.The decode for the navdata files is at: http://ops.precisionmanuals.com/wiki/NAVDATA_Data_Dictionary use this to compare for yourselves what Navigraph is provided for ILS data.Maybe cross checking the FS Map and the AFCAD, to make sure it agrees?The only problem I have seen in the past couple of years with ILS data (besides the obvious FS out of date) is if there are LOC and LDA approaches and both are listed in the navdata then only the first one is selected by the FMS, which means Navigraph is supposed to provide the LOC freq first. They fixed this right after they started providing terminal data.I notice both problems are in the UK, is that a coincidence?My suggestion is to verify MSFS and navdata agree, then provide screen shots.

[beefix 2]

Hi there DanI've tried to sort this out using the Cessna 172. OK, the official AIP Insrument Approach Chart starts the procdure at D10.3 at 2500 ft the glide slope then starts at D7.3. The Cessna picked up the ILS signal but when I tried an auto land it just flew straight on. However, if I stared the procedure at 2000ft all was well. I've now tried it using the 737 and,low and behold, it works a treat both in manual and auto land.RGDSSteve Honey