HALIFAX -- Canada's fleet of geriatric Sea King military helicopters has finally reached its long overdue retirement on the East Coast, and the Royal Canadian Air Force is making sure the venerable, snub-nosed workhorse gets a proper send-off after 54 years of service.

The Sikorski CH-124 Sea Kings have been a familiar sight in Halifax for half a century, but many people stopped to watch Friday as three flew in close formation above the city's harbour to mark the final days before the aircraft officially ceases Atlantic operations next week.

"We are now downing tools on Sea King operations on the East Coast so we can put our full efforts into transitioning aircrew and technicians to the new Cyclone," said Col. Sid Connor, wing commander at 12 Wing Shearwater. "It's bittersweet for the technicians and aircrew here at 12 Wing."

The Sea Kings operating on the West Coast at Patricia Bay near Victoria will remain in operation until the end of this year as crews from that base are trained to fly the new CH-148 Cyclone, which has been plagued by delays and cost overruns.

"Sure, there has been a bit of delay here and there," said Lt.-Col. Jody Smith, commanding officer of 423 Maritime Helicopter Squadron. "However, the people within the maritime helicopter community understand the importance of getting it right."

The first Sea Kings arrived at Shearwater on Aug. 1, 1963, and were expected to serve mainly as submarine hunters to deter the former Soviet Union from violating Canadian sovereignty.

At first, the big choppers were placed on aircraft carriers, but that role ended in the 1970s when the big warships were scrapped.

And so began the story of the Sea King's constant reinvention. Over the years, these machines have had to adapt to a variety of missions as their operational lives were repeatedly extended.

Without aircraft carriers, the helicopter was modified to land on smaller, less stable warships, during even the harshest conditions.

"We were really the first ones to do that with the development of the beartrap system," said Connor, referring to the innovative cable system used to reel in Sea Kings landing on the rear flight deck.

During the Cold War, Sea Kings were regularly dispatched for missions near Norway, where they lured Russian ships and submarines from their ports.

And as its surveillance and weapons systems evolved, Canada became a world leader in anti-submarine warfare, the helicopter acting as the "eyes and ears" for Canadian warships.

"We were able to more than hold our own as a relatively small navy," Connor said.

In more recent years, the vintage helicopters have run into a series of mechanical problems, some of which forced landings in schoolyards and parking lots.

The procurement process aimed at replacing the helicopters started in the mid-1980s, but politics and technical challenges soon got in the way.

In 1992, the Progressive Conservative government led by Brian Mulroney decided to purchase 50 of E.H. Industries' EH101 helicopters for $5.8 billion, but that decision was scrapped in 1993 when Jean Chretien's Liberals won office. The newly minted prime minister said the EH101s were unaffordable "Cadillacs."

That decision cost the federal treasury up to $500 million in contract cancellation penalties, and it forced the military to refit the Sea King for new roles, such as supplying troops during the Somalia mission and providing surface surveillance in the First Gulf War that forced Iraq to withdraw from Kuwait.

In 2003, after numerous redraftings of the original specifications, the Liberal government chose the military version of the Sikorsky S-92, later dubbed the CH-148 Cyclone. But there were warnings the Cyclone was an untested design that could take many years to properly adapt to the Canadian military's needs.

Still, the federal government signed a $5-billion contract with U.S.-based Sikorsky to buy 28 Cyclones, the first of which was supposed to arrive at Shearwater in 2008.

Since then, there have been disputes over the readiness of software needed to run the aircraft, and Sikorsky has blamed repeated delays on changes the military has demanded to the design, including a requirement for stronger engines.

In October 2010, the federal auditor general harshly criticized the Cyclone project, saying cost overruns had hit $700 million.

The first "interim" CH-148 Cyclone arrived at Shearwater in May 2011. But that model was for ground-based training only.

Connor said the Royal Canadian Air Force now has eight Cyclones. He said he expects to have one fully operational within the next six months.

The remainder of the helicopters are expected to be fully operational by 2021.

Meanwhile, there are six Sea Kings still flying on the West Coast and, for a few days longer anyway, another four or five on the East Coast.