 In 1963, the 11th Air Assault Division was activated to test a number of the Board's concepts and recommendations about air mobility.Because the 155mm howitzers then assigned to Army divisions as medium support artillery were not transportable by helicopters, the concept of aerial rocket artillery (ARA) was developed as a substitute.The original test unit for rocket-armed helicopters within the 11th Air Assault Division was the 2nd Battalion, 42nd Artillery (later designated the 3rd Battalion, 377th Artillery).