Definition
A Changeover Point (COP) is a published location along a Victor or jet airway between two VOR navigation aids that tells a pilot where to switch navigation reference from the VOR behind the aircraft to the VOR ahead. COPs are normally placed at the midpoint between two VORs, but are relocated when terrain, signal interference, or airway geometry makes reception from one station unreliable past a different point. They are depicted on en route charts with a distance figure showing miles to each VOR.
Plain English
A spot on an airway that tells you when to stop using the VOR behind you for guidance and start using the VOR ahead.
Context Anchor
Seen on IFR en route charts and in route information when flying along airways or other routes based on VOR navigation.
Derivation
Changeover point is plain English -- the point at which you change over from one VOR to the next. The word's structure already explains the concept; it is named here mainly to flag that COPs are charted, fixed locations rather than something the pilot decides on the fly.
Why Pilots Care
Keeps the navigation signal strong and continuous as the aircraft moves out of range of one VOR and into range of the next.
Intuition Check
Do not think of a COP as just a convenient place to change frequencies. It is the intended point for switching navigation guidance from one VOR station to another.
Example Sentence 1
Approaching the COP, the pilot retuned the second VOR and confirmed the new course before continuing along the airway.
Example Sentence 2
Charts show COPs so pilots know the best place to change navigation sources between two VORs.