The pilot was to fly three passengers from Great Barrier Aerodrome to Auckland Airport. She commenced taxiing the aircraft at a slow walking pace from the parking area to the take-off point for runway 24. The rising sun shining through the windscreen from a low angle made taxiing difficult and the pilot did not recognise that the aircraft was tracking toward a 1.5m deep drainage ditch. The pilot sighted a marker tyre in an unexpected position but was unsuccessful in an attempt to change the aircraft's direction. None of the occupants were injured but the aircraft was substantially damaged when it entered the ditch.