The article fails to mention ILS integrity monitoring systems. They are mandatory for Cat II and Cat III operations. ILS degradation is a well-known risk and c

The article fails to mention ILS integrity monitoring systems. They are mandatory for Cat II and Cat III operations. ILS degradation is a well-known risk and concerns are mostly associated with environmental effects like signal reflections from other aircraft or airport vehicles. 1979 FAA report "Far Field Monitor for Instrument Landing Systems" explores the issue in depth: https://apps.dtic.mil/dtic/tr/fulltext/u2/a079663.pdf https://apps.dtic.mil/dtic/tr/fulltext/u2/a079663.pdf