View Full Version : B737NG FMC message

19th Mar 2010, 23:36
Got an "AUTO/MAN FREQ MISMATCH" FMC message on my previous flight, have not been able to find out what it means... anyone in here who might know?

20th Mar 2010, 09:57
Check to see if the FMC data base has been loaded/changed - could be the new software.
Might have something to do with auto DME tuning by the FMC.:ok:

20th Mar 2010, 11:14
It means you had an incorrect ILS frequency selected for the airfield designated as 'Destination' in the FMC.

20th Mar 2010, 14:18
Wouldn't that be RW/APP TUNE DISAGREE (or FMC APP/TUNE DISAGREE, NAV INVALID TUNE)? Didn't find the message quoted by the OP either so kinda curious what it is. What FMC-Version are you using?

20th Mar 2010, 19:45

It means the manually selected frequency the FMC operates on is different from the frequency it would have selected itself in your area of operation.

Did it also at one point say "ACARS NO COMM"?

If it didn't I bet it was scanning the wrong frequencies and one of your colleagues manually selected the european ACARS frequency. I think it's 131.75.

Select MENU - ACARS - MISC - FREQ. There you can select Automatic- or manual ACARS frequency.

NCB.. Norsk? Skulle det være en annen grunn så send meg gjerne en privat melding.

Cheers :ok:

20th Mar 2010, 19:52
ACARS frequency selected does not match position database. Could be a bug in a recent software update unless VHF 3 was manually mistuned tuned during that leg.