From the viking Air web site.

"Viking is the owner of the Type Design and Certificates relating
to de Havilland Aircraft product lines; DHC-1 Chipmunk, DHC-2 Beaver, DHC-2T Turbo Beaver, DHC-3 Otter, DHC-4 Caribou, DHC-5 Buffalo, DHC-6 Twin Otter, DHC-7 Dash 7."