Furuno 520 - Manual (Page 58)

5. ALARMS
5-8
5.1.10 Clearing the trip distance
You can reset the trip distance to zero as follows.
1. Rotate the course control knob to select “CLEAR TRIP LOG” from the
ALARM SETUP menu.
2. Press the course control knob to show the log trip clear options window.
YES
NO
Log trip clear options window
3. Rotate the course control knob to select “YES” to reset the trip distance.
4. Press the course control knob.