COPENHAGEN, Denmark (AP) — A ship equipped with a sturdy crane has arrived in Arctic Norway and will attempt to raise a Russian helicopter that crashed off the Svalbard archipelago with eight people onboard.

William J. Bertheussen of Norway's Accident Investigation Board said it was unclear when the Maersk Forza could raise the chopper. He said several factors including weather and darkness could hamper the operation. At this time of the year, it is dark for nearly 20 hours on Svalbard.

So far, only one body has been recovered from the Mi-8 helicopter's wreckage, located at a depth of nearly 210 meters (about 685 feet.)

The helicopter with five crew members and three members from Russia's Arctic and Antarctic Research Institute went down Thursday near the settlement of Barentsburg.