The Cold War was in one of its most serious periods, and the global situation was tense. In a future world war, Sweden would be protected by a strong defence and non-alignment. During a period, the country also had one of the strongest air forces in the world. Sweden had secretly started intelligence cooperation with Britain, an ally of the United States. That meant that information from Swedish reconnaissance flights would also be available to the Americans. The Soviet Union knew about this secret cooperation through Swedish spy Stig Wennerström.
It is against this background that the DC-3 Hugin took off for its last flight on 13 June 1952 with a crew of eight. Three were Air Force personnel, and the other five were from FRA, the Swedish National Defence Radio Establishment. The mission was to use radio intelligence to gain more information about how the Soviet Union had built up and organised its air defence. This was no new development, as these missions had been run continually for several years. Everything was top secret but not illegal. The DC-3 was unarmed and flew without accompanying fighters.
The plane that disappeared
At 09:05 a.m., the DC-3 took off from Bromma Airport. The Swedish plane followed its planned route and reported its position back to Sweden. Just before 11:30, a Soviet fighter attacked. The DC-3 sent an interrupted emergency call. After that, there was silence.
An intensive rescue action was commenced. After two days, a lifeboat was found with shrapnel damage. The next day, a second plane, a Catalina helping in the search, was shot down in a Soviet attack. The crew survived, but the search for the DC-3 was terminated.
Sweden began an exchange of notes with the Soviet Union. The newspapers were filled with headlines about war and the mood was bitter. Air Force Chief of Staff Nordenskiöld issued orders that Sweden should open fire if threatened from the east. The mission of the DC-3 was deemed too much of a secret to reveal, and the event was quieted by focusing attention on the Catalina matter. The Soviet authorities denied any involvement in the fate of the DC-3. In Sweden, the truth was kept from the relatives of the victims, and a series of theories about the plane and its crew appeared. This was the beginning of a long period of waiting, mourning and uncertainty.
Through the ensuing years, several enquiries were made with no results. In 1991, when the political climate was more open, the Soviet Union finally admitted that it had shot down the plane. More than 50 years after the event, a privately-financed group took the initiative to search for the plane. In 2003, they found the DC-3 in the Baltic Sea at a depth of 125 metres.