The flagship vessel in the Royal Canadian Navy's East Coast fleet had to be called back to Halifax from deployment because of serious engine problems.

HMCS Athabaskan — the navy's last destroyer — has been in service for 43 years and is starting to show its age. It needs major repairs to the propulsion system and there are other engine issues, the navy said Monday.

"We're not able to control the engines and they were using secondary means to run the engines," said Rear Admiral John Newton. "For that reason the ship was brought home from the Operation Caribbe mission, the counter-drug mission in the Caribbean Sea and brought home to work on it."

Newton said he saw the ship in Halifax on June 22.

There are also questions about the ship's weapons systems.

"I don't think it's a surprise to anyone, based on the age of the ship, that some of her primary warfare systems — we would not rely on them in this modern era," Newton said.

"It's not like we're being denied fleet size or fleet capability. We have lots in our account right now and our job is to employ it effectively."

Ken Hansen, a military expert, disagrees.

"I think it is highly probable the Athabaskan will never sail again," said Hansen, a research fellow at Dalhousie University's Centre for Foreign Policy Studies.

"The problem is that you couldn't send Athabaskan anywhere and reliably expect her to get there or to get home again. She's going to break down. You've got to be able to move to fight," he said.

"If the navy thinks … that sending Athabaskan sends a strong signal to the Russians — it's the wrong kind of signal. It's a signal that says Canada's navy has crapped out and they don't have to be worried."

HMCS Athabaskan is scheduled to take part in a large military exercise in October, as part of NATO. Hansen called that plan a "bad diplomatic move," given the state of the vessel.