In order to calculate Ground Speed, you must be on what navigational feature?

In order to calculate Ground Speed, you must be on what navigational feature?

• A. On radial of a NAVAID
• B. On a VOR station
• C. On a GPS waypoint
• D. On a localizer course

Answer: (A)

Ground speed is the distance you travel over the ground divided by the time it takes. To measure that distance reliably on a leg, you want a clearly defined track you can follow. A VOR radial provides a fixed line from the station, so when you’re on that radial you can use distance-to-the-station (with DME or timing changes) to determine how far you’ve moved along that line in a given interval. That defined track lets you calculate your speed over the ground along that direction. Being on a VOR station itself doesn’t give you a leg to measure, GPS waypoints can be arbitrary, and a localizer course is for approach alignment rather than enroute ground speed, so the radial from the navaid is the appropriate feature for this calculation.

Ground speed is the distance you travel over the ground divided by the time it takes. To measure that distance reliably on a leg, you want a clearly defined track you can follow. A VOR radial provides a fixed line from the station, so when you’re on that radial you can use distance-to-the-station (with DME or timing changes) to determine how far you’ve moved along that line in a given interval. That defined track lets you calculate your speed over the ground along that direction. Being on a VOR station itself doesn’t give you a leg to measure, GPS waypoints can be arbitrary, and a localizer course is for approach alignment rather than enroute ground speed, so the radial from the navaid is the appropriate feature for this calculation.