flying from KAUS to KPDX i am n nearing my TD for a 28R approach to Portland. I get a message across the Nav screen that said "EFIS MODE/NAV FREQ DIASGREE" and I loose the route on the nav screen. I just shows a straight purple line forever with no fixes etc. I had the 28R freq tuned on both recievers and the course on both course indicators. Anyone know what happened?Don Emerson736-900

Mate; I think I know, Your AIRAC cycle is using a frequency that is newer than the one FSX uses. You always have to remember that FSX is a ~ 2006 world and using an AIRAC for 2011 is likely to cause such issues.To be sure that's the cause you have to check the freq's from FSX itself (use the flight planner) then go in the PMDG / navdata folder and look in the navaid text file. Make a search for the name of the ILS you want and you should be able to spot the discontinuity. To fix that you have 3 options. 1. Use the free AIRAC from 2006 from the navdata site.2. Get an addon airport for your destination or a just a file that corrects the new frequencies.3. Modify your AIRAC. Hope I was of use :(

My thoughts too. I dropped down the FSX map and checked the freq and it was the same as my current NAVDATA. 111.3The only thing that comes to mind is when I took off from Austin I had selected 28L and changed to 28R in route but I changed the freq and my approach page showed 28R. So the newer airac and the old fsx agree on the frequency.Don Emerson570TT

I do have ORBX scenery for that area maybe they changed the freq from the original.Don Emerson570TT

I must have put in incorrect freq for the ILS 228R but don't think so.. This afternoon Ii made an approach to 28R from a nearby airport and everything worked out great. who knowsDon