Final answer:
The requirement to monitor underlying traditional NavAids during an Overlay approach varies and is dependent on the reliability of GPS, the certification of the aircraft's systems, and the regulations of the governing aviation authority. Pilots must be aware of and adhere to the specific regulations and operational requirements.
Step-by-step explanation:
When utilizing an Overlay approach, which involves the use of GPS or other advanced navigation systems superimposed on traditional routes that are defined by ground-based NavAids like VORs and NDBs, the requirement to monitor the underlying traditional NavAids can vary. Traditionally, pilots were required to monitor these aids to ensure redundancy and accuracy of the flight path. However, with the improved reliability and precision of GPS, some modern aircraft may not require constant monitoring of these traditional aids when conducting an Overlay approach, especially if the aircraft's systems are certified for such operations and the regulatory body overseeing the flight operation has approved GPS as a primary navigation source for that particular procedure.
However, pilots must always be aware of the current regulations and operational requirements for the airspace they are operating in, as these can differ. For instance, in certain situations or regions, authorities may mandate the monitoring of traditional NavAids as a backup to GPS, particularly in areas where GPS signals are known to be unreliable or susceptible to interference. Therefore, it is crucial for the flight crew to be well-informed about the specific approach procedures and the regulatory requirements related to the use of navigation aids for the flight they are conducting.