Definition
A navigation aid (NAVAID) is any ground-based or space-based facility that transmits a signal pilots use to determine position, track a course, or fly a published route or procedure. Common examples include VOR, NDB, DME, ILS, TACAN, and GPS satellites.
Plain English
A NAVAID is a piece of equipment — usually a ground station or a satellite — that sends out a signal so pilots can figure out where they are and where they're going.
Context Anchor
Seen in instrument flying and federal airway discussions, where routes are often built around navigation aids.
Derivation
Short for 'navigation aid.' 'Navigation' comes from the Latin navigare, meaning 'to sail or steer a ship.' Aviation borrowed the term wholesale from maritime use — pilots, like sailors, need fixed reference points to steer by, and NAVAIDs are those reference points in the sky.
Why Pilots Care
NAVAIDs let pilots fly accurate routes and maintain safe separation even when they cannot see the ground.
Intuition Check
Do not read navigation aid as just any helpful item, like a paper map or a tip from another pilot. In FAA use, it usually means a recognized facility, signal, or system that provides navigation information to aircraft.
Example Sentence 1
The Victor airway between the two airports is defined by a series of VOR NAVAIDs along the route.
Example Sentence 2
Controllers confirmed the navigation aid was operating before clearing the flight for the route.