Flight crew reported that while on vectors to intercept the final approach course; the aircraft turned too early on a false localizer capture. Captain stated this had happened to other crews on this approach and cited 5G as possibly contributing.
Synopsis
Flight crew reported that while on vectors to intercept the final approach course; the aircraft turned too early on a false localizer capture. Captain stated this had happened to other crews on this approach and cited 5G as possibly contributing.
Narrative
Pilot Monitoring: At 3000 ft. MSL on base leg; set up and with good audio ID and sensing for the IHWM 110.7 ILS Runway 4L to ILN we got a false capture about 10NM prior to the final approach course. The PF (Pilot Flying) was in HDG Select; Alt Hold; on an intercept heading base leg to KNITE (the fix prior to the FAF CUBLA) when the LOC went straight to capture and started turning the aircraft 90 degrees left on to a false final approach course approx. 10NM west of ILN. I have heard of this exact thing happening to that runway and approach before with another crew; and after seeing it happen today decided it needs [to be reported]. The PF clicked off the autopilot; asked me to turn off his flight director; and hand flew the rest of the approach visually in clear day; VFR conditions with an uneventful landing; taxi; and shutdown. I; the PM (Pilot Monitoring); gave us a course fix intercept of 044 (Final Approach Course) from the FAF CUBLA; and turned my flight director back on; to back up the PF who executed a flawless landing visually using the PAPIs; VPI; and Glide-slope. If this is indeed not the first time this has happened; some investigation into what could be causing false LOC captures at ILN on Runway 4L should be done. The story I heard about this happening was before 5G was in effect - I'm not sure if that contributed to our event today.
Second reporter narrative
During the approach and arrival phase of the flight; we were being vectored for the ILS 4L at ILN. The ILS had been properly identified and we had true sensing when cleared for the visual to Runway 4L. Between 10 and 5 miles to the final approach course; the airplane appeared to capture the localizer and began to turn like it was actually on the localizer. It was clear both visually and based on the course depicted on the HSI that we were turning to parallel the localizer course. I turned off the autopilot and had the PM (Pilot Monitoring) clear my flight director. I continued without re-automating and landed without further issue.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.