Canada first operated the Chinook from 1974-91 - those CH-47C models were subsequently sold to the Netherlands. After quite a long gap, with operations in Afghanistan a major focus it then bought six CH-47D models from the US Army, with service entry from 2008; in line with its own aircraft designation system, Canada dubbed these the CH-147D. These were followed by 15 new-build CH-147Fs delivered in 2013-14. The latter are operated by 450 Tactical Helicopter Squadron at Petawawa, Ontario. The Royal Canadian Air Force says these new Chinooks can fly twice as far as their predecessors in Canadian service, a vital capability on domestic operations given the country's huge size. They support the Canadian Army and Special Operations Forces, other government departments, law enforcement agencies and civil authorities.