During an ILS approach, what should a pilot do if the localizer signal is lost?

When flying an Instrument Landing System (ILS) approach, the localizer provides lateral guidance to ensure proper alignment with the runway. If the localizer signal is lost, the safest course of action is to abort the approach immediately. This decision is critical because without the localizer signal, the pilot cannot maintain the correct lateral path to the runway, which could lead to dangerous situations such as spatial disorientation or misalignment during landing.

Aborting the approach allows the pilot to climb away from the terrain and re-evaluate the situation, which may involve climbing to a safe altitude, returning to a holding pattern, or diverting to another airport. It provides the opportunity to regain the localizer signal if it is temporarily out, or to ensure a safe approach by considering alternative procedures.

In an approach where the localizer is lost, continuously monitoring the glide slope or using alternate methods to proceed to the runway without the localizer may compromise safety. Additionally, although requesting vectors from ATC is an option, it is not the first priority in this scenario; the loss of the localizer requires immediate action to avoid potential hazards.