What is Established?

Surprisingly, the FAA is not the place to look for a definition of established. The AIM and the Instrument Flying Handbook say nothing on the topic. Only in the Instrument Procedures Handbook (FAA-H-8261-1A) does a definition pop up, and it just says that ICAO defines established as within half-scale indication on a localizer or VOR course. Useful, but there must be more.

Editorial Staff

Monday, August 04, 2014 at 12:00 AM ET

Verified

Key Takeaways:

While the official definition of "established" is within half-scale indication on a localizer or VOR, practical application often allows for flexibility due to protected airspace and system tolerances, such as initiating descents slightly early at traditional navigation fixes (DME, VOR radials).
For GPS-guided turns at "fly-by" fixes, the system anticipates the turn, which may cause the CDI to remain centered even before the aircraft is truly established on the outbound course; pilots should typically wait until abeam the fix or until the GPS sequences to the next leg before initiating a descent for that segment.
Understanding the precise meaning of "established" for different navigation types and knowing your specific avionics system are crucial for maintaining precision, ensuring regulatory compliance, and making safe, informed decisions in instrument flight, despite the system's inherent safety margins.

See a mistake? Contact us.

We’ve all heard “Maintain … until established.” We fly the route and make our descents without ATC yelling (usually). But are we actually doing it right?
Surprisingly, the FAA is not the place to look for a definition of “established.” The AIM and the Instrument Flying Handbook say nothing on the topic. Only in the Instrument Procedures Handbook (FAA-H-8261-1A) does a definition pop up, and it just says that ICAO defines “established” as within half-scale indication on a localizer or VOR course. Useful, but there must be more.