The Royal Canadian Air Force (RCAF) has taken delivery of six Sikorsky-made CH-148 Cyclone maritime patrol helicopters.

The six twin-engine helicopters represent the first of 28 Cyclone aircraft that the Connecticut-based company “will deliver to the Canadian Armed Forces to perform a full range of anti-submarine and anti-surface warfare, search and rescue, and utility missions in various environments,” the company says.

Two more CH-148s are due to arrive at the RCAF’s Shearwater operating base in Nova Scotia this December. The aircraft are slated to replace the decades-old CH-124 Sea Kings, which the Canadian military will start retiring in 2018.

“Sikorsky will introduce increased capabilities that will be phased in while the Royal Canadian Air Force determines operational strategy and more personnel are trained to fly and maintain the aircraft. More than 40 military personnel have completed initial training already,” the aircraft manufacturer says in a statement.

“In addition to today’s deliveries, Sikorsky will continue developing and enhancing the capability of the Cyclone to meet all of Canada‘s required operational capabilities,” says William Gostic, vice president of Sikorsky’s CH-148 Maritime Helicopter Program (MHP).

The CH-148 Cyclone “will be the world’s most advanced maritime helicopter,” add Gostic, hailing the delivery as “a major milestone for the Canadian Armed Forces.”

DELIVERY COMES AMIDST SOME CONTROVERSY IN CANADA

The delivery of the new helicopters comes amidst a flurry of controversy in Canada as the Cyclone program has been beset by technical issues, delays, and numerous contract revisions since its start-up in 2004.

Canadian Public Works and Government Services Minister Diane Finley says it’s a “great pleasure to finally put the Sea King workhorse out to pasture. I’m not one to mince words. The Cyclone has been a complex procurement—one that has seen its share of challenges. In fact, this procurement has had a torturous history.”

The total value of the Cyclone acquisition is $6.2 billion, including $1.5 billion for development and production of 28 helicopters and $4.6 billion over 20 years for in-service contractor support.

Sikorsky recently signed a contract to supply an S-92 helicopter—the civilian version of the company’s CH-148 military helicopter—to Alaska’s North Slope Borough, the northernmost municipal government in the U.S.

The Borough encompasses an area of nearly 95,000 square-miles across northern Alaska including eight communities and the Prudhoe Bay oil fields.