I encountered a significant issue with my aircraft's navigation and auto-landing systems during my most recent flight. While on approach, the VNAV function unexpectedly failed, causing the aircraft to maintain a constant altitude of 10,000 feet, regardless of the pre-set altitude of 4,000 feet. This was followed by an excessively steep descent initiated by the ILS system. Furthermore, I've noticed that at certain airports, ILS approaches often result in the aircraft being misaligned with the runway centerline."
