This program is designed to help glider pilots using only a GPS to decide when the FAI 90° quadrant (sector) at each turning point (TP) has been entered.
If you have access to TaskNAV, you can derive the safe bearings without using TurnSafe, as follows:
- Draw the task using Graphics Editor
- Select Print | Standard Task Report
- Note down (or print out) the bearings given in the Bis[ector] column
- For a clockwise task, subtract 40° from each bisector; for an anticlockwise one, add 40°
- Skip to step A.7 below
- Before flight
- Type in Start, Finish and TP names
- Type in bearing for each leg (preferably from GPS Routes page—or map)
- Leave unused TP lines blank—but fill in final leg bearing on Finish line
- Click on Calculate button
- Make a note of (or print out) the "safe bearing" for each TP
- For an out-and-return task 2 bearings are given: the first applies if you turn the TP clockwise, the second if you turn it anti-clockwise
- Make sure your GPS displays Bearing (to next waypoint) on the map page (you may have to use the Change Fields option on the menu)
- Activate the "route" (task) on your GPS
- In flight, approaching each TP
- Fly beyond and around the TP (ie to the left for a clockwise task; otherwise to the right).
- Monitor the TP bearing on your GPS (it will be increasing in a clockwise task; otherwise decreasing)
- As soon as you have passed through the "safe bearing", you can be sure that you are in the FAI quadrant (with a 5° safety margin). You can now fly straight towards the next TP.
If you find this program useful, you are welcome to download this webpage for use offline. Simply click File | Save As ... to your hard disk.
Last revised June 2004
© N Greenwood 2004
Comments or suggestions