ACE Airfield Operations Module 3 Practice Test 2026 - Free Airfield Operations Practice Questions and Study Guide

Category I ILS is the standard precision approach that provides both lateral guidance from the localizer and vertical guidance from the glideslope, with defined minimums to guide descent toward the runway. It isn’t just a localizer-only (non-precision) setup, since the glideslope adds the vertical guidance that characterizes a precision approach. It isn’t described as glideslope fail-safe, because the system is monitored and serviceability conditions, not a label of failure protection, define when the approach can be used. It also isn’t about automatic landings in zero visibility; automatic landing capability is associated with higher CAT levels, not CAT I. So the best description is the standard/basic ILS system.