Here is a simplified account of a flight from Semmes to Crestview:
1. Tune and identify the Semmes VORTAC.
2. Fly on its outbound radial for half the distance of the jet route segment.
NOTE: In this case the radial and the course are both 081° magnetic.
3. At the halfway point (43.5 DME), tune and identify the Crestview VORTAC.
4. Fly inbound on the 263º radial of the Crestview VORTAC.
NOTE: In this case the radial is 263º and the inbound course is the reciprocal, or 083º.
It should be mentioned that while the chart (Figure 11) shows the J-2 route as a straight line,
the course actually differs by 2º. This is caused, in part, by a change in the Earth's magnetic
variation between the navaids.
Continuing east from Crestview towards Tallahassee on J-2, you will notice that the airway is
NOT a straight line. It has a "Dog Leg" 80 (28+52=80) miles east of Crestview. (Figure 12)
The procedures for flying this leg of J-2 are basically the same as the Semmes to Crestview
leg. In this case the position at which you change navaids differs from the "halfway" rule.
When flying J-2 from Crestview to Tallahassee, change navaids at the mileage breakdown point
depicted on the chart. Your inbound flight to Tallahassee would be on the 288° radial (Course =
Another exception to the rule of changing navaids halfway along your route of flight occurs
when you encounter a "changeover point". Figure 13 depicts J-118 between Memphis and
Chattanooga. If you were flying easterly along J-118 you would not switch your navaid at half
the distance (238/2=119). You would switch it at the changeover point (130 DME).
RADIAL TRACKING AND COURSE CONTROL 3-9