Commercial Fixed Wing
Confusion
ATC Issue All Types; Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew FLC Overrode Automation; Flight Crew Returned To Clearance
ATC Equipment / Nav Facility / Buildings; Aircraft
Some phantom signal near the extended centerline of 27R. I didn't write the plane up because it seemed like the localizer frequency and aircraft is working just fine. I think it's just a random signal that's enough to trick the plane. Arriving on the WYNDE arrival to ORD; on a dogleg to final 27R; the autopilot coupled to the localizer and began a hard right turn long before the localizer was centered. It may have been sensing another signal. After disconnecting the autopilot; I turned back to the localizer and now was trying to fly visually because I didn't trust the loc signal. We did briefly go through the localizer; as I picked up the wrong runway at first; but we weren't more than a dot off on the short range and the signal seemed fine the whole time. I'm writing this report; because this seems to happen all the time with 27R in ORD. It seems like a safety issue to me.
Air Carrier Captain experiences localizer anomaly joining the LOC for Runway 27R at ORD. The autopilot appears to capture the LOC well before it is actually reached. The autopilot is disconnected and the approach flown manually with all localizer and glideslope indications appearing normal.