Final Answer:
When the localizer fails, an ILS approach is not authorized.
Step-by-step explanation:
The Instrument Landing System (ILS) is a critical navigation aid for aircraft during approach and landing. It consists of two main components: the localizer and the glide slope. The localizer provides lateral guidance, ensuring the aircraft is aligned with the runway centerline. If the localizer fails, it compromises the accuracy of lateral guidance, and an ILS approach becomes unsafe.
Without a functioning localizer, pilots may lose the precise alignment needed for a safe landing. The localizer failure could result from various issues, such as equipment malfunctions or interference. In such cases, pilots rely on alternative navigation methods or may execute a missed approach to ensure the safety of the flight.