Svalbard had since its settlement in the early 20th century been entirely isolated from the world during winter, when ice closed its ports.

As a trial, the air force carried out a postal delivery expedition in April 1949, dropping mail at Longyearbyen, Ny-Ålesund and Sveagruva.

[1] The aircraft was a Boeing-Canada PB2B-1 Catalina IVB—a version of the Consolidated PBY Catalina—with construction number 28129 and the Squadron code of KK-N.

[4] In addition there was a passenger, a journalist from the Norwegian Broadcasting Corporation, who was making a radio program about the flight.

Originally the broadcaster had appointed Jan Frydenlund to the task, but when it became clear that the flight would be delayed by several days he was replaced by local radio journalist Sigvart Tingvoll.

[4] On the return leg from Hopen the aircraft followed a route via Bjørnøya, approaching the island from the northeast.

He had attempted to make contact again just before impact, which was thought by the investigation commission to be possibly because the crew had discovered something wrong with the aircraft.

[6] The investigation commission concluded that the accident was caused by the aircraft losing altitude, falling into a sideslip and descending into the ground, first hitting it with the right wingtip.

The varying weather with pockets of good and poor visibility led the commission to believe that the aircraft could have flown into an area with fog and lost sight of the horizon.

It reported that the accident took place towards the end of a very long flight and that fatigue could have reduced the pilots' faculties.

Because of the aircraft's poor insulation, Olsen was wearing a leather jacket and a sheepskin sweater, which kept him warm until he was rescued.

[4] The RNoAF initiated rescue preparedness three-quarters of an hour after estimated time of arrival to Skattøra.

Four Royal Norwegian Navy ships, Andenes and Sørøy and two minesweepers, were dispatched to participate in the operation.

[3] The distress call was received by the crew at Bjørnøya Radio and they decided to send two men, Einar Strand and Alv Alvær, to look for the aircraft on the island.

After an hour of searching in one meter (3 ft) deep snow, the two spotted the aircraft, which they quickly identified as they saw flames.

He left his flashlight with Olsen so that he could find him again, although even with this aid relocating the stranded survivor proved difficult, as this part of Bjørnøya is flat and there were no visual references to help orient the searchers.

In the end Olsen decided that further help would not come in time and started following Strand's footsteps, but he soon had to give up, having traversed about 200 meters (660 ft).

By then a winter airport had been built in Adventdalen outside Longyearbyen and Braathens SAFE took over the postal flights.

[11] The 333 Squadron commemorated the accident on its 50th anniversary in 2004 by flying two Lockheed P-3 Orion aircraft over Bjørnøya and dropping flowers over the site.