Definition
Ground- or space-based equipment that transmits signals pilots use to determine position, track a course, or fly an instrument approach. Common examples include VORs, NDBs, ILS components, DME, and GPS satellites.
Plain English
Equipment on the ground or in space that sends out signals so pilots can figure out where they are and where they're going.
Context Anchor
Seen in NOTAMs, which are official notices to pilots, when a navigation aid is out of service, unreliable, or operating differently than expected.
Derivation
Short for 'navigational aids.' 'Navigate' comes from the Latin navigare, meaning to sail or steer a ship. The term moved from sea to sky as aviation borrowed maritime language for finding one's way.
Why Pilots Care
They provide critical position and course guidance, especially when weather reduces visibility.
Intuition Check
Do not assume NAVAIDs are only physical objects on the ground. In aviation, the term can refer to the system, facility, or signal that helps navigation.
Example Sentence 1
Before departure, the pilot checked NOTAMs and saw that one of the NAVAIDs along the route was out of service.
Example Sentence 2
Modern aircraft often use multiple NAVAIDs to cross-check position during instrument approaches.