I planned a route in charts and a leg starts in a VOR, to figure out the outbound radial of the VOR I checked the degrees indicated in that leg of the route, as far as I know they include the magnetic variation, so it should be the same as the outbound VOR radial to be followed. But while flying that leg, while following the mentioned outbound radial figured out as explained, I checked my actual position in Charts and I noticed I was not in the right path, seemed I was in another radial, not the one indicated. Can you explain me what am I missing?
As far as I know, Navigraph Charts leg bearings use an up-to-date magnetic variation model.
On the other hand, VOR radials use a fixed magnetic variation, which would have been current at the time they were last calibrated, sometimes decades and decades ago.
airnav shows the magnetic variation at a specific VOR (the difference between the true heading and the radial), for example, the Akron VOR/DME in Colorado:
AKO
AKRON VOR/DME
AKRON, CO
Location
Lat/Long: 40-09-19.998N / 103-10-46.973W (40.1555550/-103.1797147)
Elevation: 4623.2 ft.
Variation: 13E (1965)
The VOR’s variation is 13 degrees East, last set/updated in 1965.
According to the NCEI website: NCEI Geomagnetic Calculators
Today’s magnetic declination at the VOR’s coordinates is approximately 6.48 degrees East, so the difference is quite huge.
The same website puts the historical declination in 1965 at 12.62 degrees East, which explains why it was set to 13 East back then.
Regards,
Tim
I understand now, many thanks Tim