A319
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Returned To Clearance
ATC Equipment / Nav Facility / Buildings
Executing MMMX ILS DME 2 05R approach; descending MAVEK inbound on 164 track; and with Approach Clearance. Aircraft was in Nav; Managed Descent; Selected Speed (160) with APPR Armed. Approximately 4 miles before MEX05 the aircraft turned left as if to intercept a LOC course. Pilot Flying intervened with Heading Select in order to return to course. ATC immediately provided vectoring to final just outside PLAZA at half a dot above GS. LOC and GS capture were normal Final approach was hand-flown with correct FD guidance.The first item on the Company Arrival Ops Advisory page is a Caution. It states 'False localizer signals have been verified to exist in vicinity of MMMX.'In the majority of final approach scenarios the trigger for arming the approach is hearing 'Cleared for the approach'. Doing so in this scenario was inappropriate (too early); and in light of this episode this cautionary note is too vague. More guidance; in reference to the verified false localizer signals; is in order.
[Report narrative contained no additional information]
A319 flight crew reported the aircraft captured a false localizer on approach to MMMX.