 In 1969 the FAA issued Type Certificate A18CE and the aircraft built under that design were designated the "A" series "Super Vikings".Aside from refinements already made to late Viking 300 models, the new 300A Vikings (17-30A, 17-31A and 17-31ATC) had a gross weight increase to 3,325 lbs.The original complex fuel system with five tanks and two fuel selectors allowing eight possible combinations of selector settings was simplified to a left, right and auxiliary system in 1974.