Premise: The 337 Squadron (Norwegian: "337-skvadronen" ) is a maritime helicopter unit of the Royal Norwegian Air Force (RNoAF). Based at Bardufoss Air Station, the squadron operates eight NHIndustries NH90. The helicopters are used by the Norwegian Coast Guard and serve on the "Nordkapp"-class, the "Barentshav"-class and on NoCGV "Svalbard".
Hypothesis: there are four classes of helicopters used by the air force.