A navigational aid (NAVAID), also known as aid to navigation (ATON), is any sort of signal, markers or guidance equipment which aids the traveler in navigation, usually nautical or aviation travel. Common types of such aids include lighthouses, buoys, fog signals, and day beacons.
HINT:
Navaids in the context of Isla San Felix Airport
Isla San Felix Airport Spanish: Aeropuerto Isla San Felix, (ICAO: SCFX) is an airport serving the Chilean Navy garrison on Isla San Felix, a Pacific island that is part of the Valparaíso Region of Chile. The island is some 900 kilometres (560 mi) off the coast of Chile, and 1,100 kilometres (680 mi) northwest of Valparaíso.
The runway goes the entire length of the small island, so all approaches and departures are over the ocean. There are no published radio navaids on the island.
View the full Wikipedia page for Isla San Felix Airport