FAA Aircraft Dispatcher (ADX)Navigation and ATCHard
A dispatcher is reviewing a Victor airway segment between two VORs spaced 90 NM apart with no charted changeover point (COP). At what point along the segment should a pilot normally change navigation reliance from the departure VOR to the destination VOR?
- AOnly when instructed to do so by ATC, since pilots may not change navigation source independently
- BAt the midpoint, 45 NM from each VOR, to ensure adequate signal reception from both facilities
- CAt 10 NM prior to the destination VOR, to minimize station passage error
- DAt 30 NM from the departure VOR, to allow early signal acquisition
Show answer & explanationAnswer & explanation
Correct answer: B. At the midpoint, 45 NM from each VOR, to ensure adequate signal reception from both facilities
When no COP is charted, the changeover point defaults to the midpoint between the two navigational facilities defining the route segment (45 NM from each here), ensuring the pilot is using the stronger, more reliable signal from the nearer station for as much of the flight as possible.
Why the other options are wrong
- A. Pilots change navigation source based on charted/default COPs, not ATC instruction.
- C. That would leave the pilot relying on a weak, distant signal for most of the segment.
- D. Changing too early relies excessively on the weaker signal from the distant destination VOR.
Changeover Point (COP)
The point along a Victor airway segment where a pilot changes navigational reliance from the facility behind to the facility ahead, defaulting to the midpoint unless otherwise charted.
- Default COP is the midpoint between navaids
- Charted COPs override the default when needed for signal or terrain reasons
- Depicted on enroute charts with a mileage break symbol
Memory trick: 'Split the signal down the middle — COP at the halfway mark'