In an approach, is it acceptable to use GPS Overlays with LOC?

In an approach, the use of GPS overlays with a Localizer (LOC) approach is a nuanced topic addressed by aviation regulations and procedures. With a Localizer approach, the signals from the ground-based instrument are intended to guide the aircraft precisely along the centerline of the runway, relying on the traditional navigational aid.

When it comes to using GPS overlays, the concern arises from the fact that while GPS can provide valuable positional information, its accuracy and reliability can be influenced by various factors, including satellite geometry and potential signal interference. Combining GPS overlays with a LOC approach can lead pilots to rely on a system that may not guarantee the same level of precision expected from a traditional instrument approach, which can compromise safety.

Therefore, in this context, the use of GPS overlays with LOC approaches is not permissible as a standard practice without explicit authorization or specific procedural guidelines stating that it is allowed. This is rooted in the need for stringent adherence to established flight safety protocols and regulatory standards. The correct approach is to avoid using GPS overlays with LOC unless specified otherwise to ensure compliance with safety standards and regulatory frameworks.