Using ETCAS for an RV is fraught with error, because azimuth accuracy is insufficient! I was aghast when I heard that the USAF had been trying to use it for RV purposes....
Link16
could be used, but DF/TACAN is the simplest and safest method if the EMCON state permits.
FJ2ME, if A/A TACAN range is jumping, try using Y channels as they should suffer less from interference. Also check the AGC setting? Maybe even resort to stopwatch ranging as a back up?
Another refinement which could be added to the A310 MCS would be a Link16 SRAP overlay on the moving map....
