When is a VOR frequency underlined on an Instrument Approach Procedure (IAP)?

When a VOR frequency is underlined on an Instrument Approach Procedure (IAP), it indicates that the VOR does not have voice capability. This is important for pilots to know as it affects the way they receive navigation information. If the frequency is underlined, pilots should plan to receive only navigation guidance from that VOR, relying on the VOR's signal for course guidance rather than any audio information.

Additionally, understanding this distinction is crucial for effective navigation during instrument flight, as a VOR with voice capability typically has supplemental radio transmissions that can provide useful information, such as weather and other advisories. Knowing that an underlined VOR frequency lacks voice capability helps pilots prepare to utilize their instruments accordingly, ensuring they are equipped to manage their navigation without any additional verbal information.