1. Lay chart on knee
2. Find last two or 3 marked fixes.
3. Extrapolate OR use last known track made good OR use heading + reasonable drift allowance to give line of position
3. Note time.
4. Note last calculated groundspeed OR TAS + reasonable +/- wind adjustment.
5. Use 3. & 4. to calculated distance run.
6. Mark this DR distance along LoP.
7. Read lat. & long. from map.
8. Look at altimeter.
OR
1. Press button on GPS to read current lat. & long.
2. Go "Huh????"
3. Press other buttons to change display to Bearing/Distance from waypoint.
4. Look at altimeter.
