Definition
The ground-based and space-based navigation facilities — such as VORs, NDBs, DME stations, and GNSS/GPS coverage — that pilots use to navigate during the en route phase of flight, between departure and arrival areas.
Plain English
The navigation signals and stations that help you find your way along the cruise portion of a flight, after you've left the departure area and before you start your approach.
Context Anchor
Seen in NOTAMs and preflight planning when a navigation aid used along the planned route is unavailable, changed, or being serviced.
Derivation
‘En route’ comes from French, meaning ‘on the way.’ ‘Navigational aids’ are simply tools that help with navigation. Together: the aids that help you while you're on the way.
Why Pilots Care
If an en route navigation aid is out of service (often announced via NOTAM), it can affect the routes and procedures available for a flight. Knowing which aids are working determines whether a planned route is usable.
Intuition Check
ENAV does not name one specific instrument or station. It refers to navigation aids used along the route of flight.
Example Sentence 1
The briefer mentioned that several ENAV facilities along the proposed route were out of service, so we picked a different airway.
Example Sentence 2
Changes to ENAV coverage can require an alternate route on an IFR flight plan.