JAL flight 625 was a scheduled international cargo flight from Anchorage, Alaska, USA to Frankfurt, Germany with a stop in Copenhagen, Denmark for refueling and crew change. The aircraft landed on runway 04L at 02:15 hours. The taxiways and aprons at Copenhagen were covered with approximately 1-2 inches of loose snow with reported braking action poor. When the captain entered the apron area there was no guide line visible and taxispeed was reduced to 10 kts. Part of the apron along finger C had been cleaned for loose snow and a snow bank more or less parallel to finger C and 12-14 inches high appeared when JL625 approached the apron. The captain decided to keep the right wing gear tracking on the left side of the snow bank due to a parked DC-10 at gate 32 at the finger on his right side. Taxiing on the apron he noticed three lightmasts and judged the clearance for the left wingtip to be sufficient. He continued straight ahead close to the snowbank and when approaching gate 30 a right turn was initiated for docking. A small jolt which was thought to be the right gear boogie having encountered the snowbank was felt in the aircraft and it stopped. According to the captain’s statement he was then marshalled to continue the right turn towards the gate. But it was not possible to continue even when adding power. He then observed that the left wing had contacted and turned over a lightmast. That mast was a No. 4 in the row of previous mentioned masts noticed by the captain. It was not aligned with no. 2 and 3 mast but closer to finger C. The captain was not aware of this no. 4 mast. Cause of the Accident: “The cause of the accident was that JA 8123 was directed to and the PIC accepted to taxi on an apron with a snowbank and without a visible guideline.”