What should a pilot do if their localizer receiver becomes inoperative during IFR flight?

When a pilot experiences an inoperative localizer receiver during IFR flight, the appropriate action is to immediately notify Air Traffic Control (ATC) or Flight Service Station (FSS) of the loss. This is vital because the localizer is a key component of the Instrument Landing System (ILS) used for precision approaches. By informing ATC, the pilot ensures that they are provided with the necessary guidance and may receive alternative instructions for navigation and approach.

ATC needs to know about the loss of navigational capability to manage the airspace effectively and provide assistance, including rerouting or giving information about other available approaches. This action is consistent with maintaining safety and situational awareness for both the aircraft in question and other traffic in the vicinity.

In contrast, continuing to fly without notifying ATC could lead to violations of airspace and potential conflicts with other aircraft. Switching to GPS navigation might not be immediately advisable without prior clearance, as it depends on the current ATC procedures. Additionally, flying to the nearest airport without coordination may not align with the current air traffic situation or may lead to further complications in navigation and safety. Thus, the most responsible and correct course of action is to inform ATC about the inoperative localizer.