Regional Jet 200 ER/LR (CRJ200)
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human-Machine Interface
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Aircraft; Environment - Non Weather Related; Human Factors
We were cleared for the ILS for Runway XXR in ZZZ. ZZZ at the time was CAT II minimums showing 3/4 mile visibly and 300 feet ceilings. We started getting a LOC flag prior to final approach fix. We broke off the approach and executed a missed approach. Knowing that there are many variables as to why we would not be getting reliable LOC information we elected to try a CAT II again but to a different runway. We go set up again for the ILS for Runway XXR. While intercepting we received a LOC flag again about 18 DME from the LOC. Again knowing that there are many variables that go into receiving a good signal we decided to give it a few more miles. We caught the LOC and GS and executed a CAT II to a landing. The only thing I can think that was improper about this circumstance was the continuation of a CAT II after receiving a LOC flag. It's being 18 miles out I believe we were in some gray area. At any rate we wrote up the LOC on the aircraft so that it could be ruled out as the cause. Perhaps the LOC on Runway XXR was not strong enough or there was interference from the proceeding aircraft causing the localizer. Or it was the aircraft itself. I think we did most everything right. It just felt weird to write up the LOC after a successful CAT II approach. I didn't see any reason we shouldn't try the CAT II we had plenty of fuel and had an alternate already specified.
Air carrier Captain reported continuing with a Category II approach after receiving the LOC flag indication prior to localizer and glideslope intercept.