A320
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 133; Flight Crew Total 10000; Flight Crew Type 7000
Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Returned To Clearance
Aircraft; Human Factors
During the arrival I changed the approach from ILS XL to RNAV XXR as indicated by ATIS. The FMS auto sequenced the arrival VIA and linked the approach to the arrival. After [the waypoint] we got an ECAM (Electronic Centralized Aircraft Monitor): L/G LGCIU 1 FAULT. I continued to monitor the autopilot and the FO (First Officer) ran the ECAM. This resulted in an additional ECAM: NAV GPWS FAULT; which was caused by the previous procedure. The FO was asking 'OK to clear' and while I was looking and deciding if it was OK to clear the aircraft turned toward the first fix of the approach. I was thinking about the NAV ECAM and looking at the SD (System Display) and missed this turn.ATC immediately told us to turn right to an easterly heading and informed us that we weren't cleared to the final approach course. We complied with all ATC instructions and was then vectored to the final approach course and cleared for the RNAV XXR approach.Once on the ground we were given a phone number to. I called and spoke with the controller and supervisor. They were professional; courteous and friendly. They said that due to construction the ILS XXR is not available and they have been using the RNAV instead. Since then; they have had numerous aircraft do the same thing that we did; in fact a wide body did it the previous day. They hadn't witnessed this occurrence with the ILS; only the RNAV. I told them about how we were trouble shooting an aircraft issue and missed the automation mistake. I also said that we hadn't informed ATC about our ECAM because we hadn't gotten there yet. I explained that most ILS approaches in the Airbus 320 don't connect to the arrival but the RNAVs do. I also mentioned that we don't do many RNAV approaches and my briefing emphasis was on the approach and not the arrival. When the first ECAM occurred I should have informed ATC that we needed an extended downwind thus giving us time to clean up the ECAMs.
A320 Captain reported a fault in the aircraft navigational system during the arrival.