Issue:

This problem typically occurs when the aircraft encounters certain conditions, such as an unusual position of the LOC ground antenna or when the LOC course isn’t properly aligned with the runway axis. In these situations, the aircraft may oscillate on one side of the LOC axis, potentially leading to unstable flight or difficulty in capturing the localizer signal.

Solution:

If you encounter the Enhanced LOC capture function issue, particularly when the aircraft experiences roll oscillations during LOC capture due to an unusual LOC position or misalignment of the LOC course with the runway axis, it’s advisable to discontinue the approach for safety reasons.

During the subsequent approach attempt, the flight crew should manually tune the ILS via the Radio Management Panel (RMP) before arming the APPR mode (or the LOC mode) to ensure proper alignment and signal reception, thus mitigating the risk of encountering the same issue again.

Note – Most of the temporary abnormal behaviors’ issues are MSN specific. Check your FCOM for list of applicable issues.