ABBOTSFORD, B.C. -- More than 400 employees are on strike at the Abbotsford, B.C., company that services Canada's fleet of military transport and search-and-rescue aircraft.

Members of Unifor Local 114 walked off the job at Cascade Aerospace's Fraser Valley operations late Wednesday morning, in an apparent dispute over benefits and concessions.

The union has announced previously that the company wants to roll back benefits and force other concessions on its workers, but Cascade Aerospace disagrees.

Ben Boehm, vice-president and chief operating officer at Cascade, said his company has demanded no changes or concessions from its current workforce on issues like pensions, benefits or vacation entitlements. But the company has been focused on questions of "operational flexibility," about how to make its aircraft hangers more efficient and how personnel are employed, he said.

Still, Boehm said the company will work with Canadian government and all of its customers to ensure disruptions are minimized, and it will not call in replacement workers.

"We do have management staff that are fully qualified and certified to work on the aircraft, so we will do our best to continue with the customer commitments that we have, not just for Canada but for other customers as well."

Cascade Aerospace is owned by the Halifax-based IMP Group and is the main Department of National Defence contractor for repair and overhaul on the Hercules aircraft heavy transport fleet. It also repairs commercial aircraft for firms such as Canjet.

Unionized workers include aircraft maintenance engineers, interior technicians, painters, maintenance, planning clerks and sheet metal mechanics.

Contract talks began last February, in advance of the March 30 expiration of the collective agreement. On May 13, unionized workers voted 98 per cent in favour of strike action, and last Friday the union served the company with 72 hours strike notice.

Gavin McGarrigle, Unifor's director for B.C., said at the time the negotiations were the first under the new ownership of the IMP Group.

"The IMP approach at Cascade Aerospace is the same story we see from far too many greedy employers today--they acquire new companies, reap rewards from the skilled workers, and then demand massive concessions," said McGarrigle said in a media release.

"Skilled aerospace workers are in high demand. Treating them unfairly while rolling back benefits will only cause conflict that disrupts production," he said.

But Boehm said the Canadian aerospace companies are operating in a very competitive environment and are searching around the world, in Tunisia, Europe and Southeast Asia, for contracts.

"We are not here to in any way to punish our current employees," he said. "We want them all to have increases in their salaries and grow from that, but at the same time we have to ensure that we have an operation that's competitive and sustainable in the long term."

"We have no intention of moving anything. We're all here for the long haul. We'd love actually to expand this operation here in Abbotsford and that's really our focus."

Boehm said no new bargaining sessions are scheduled, although the company is open to talks, and he describes the current situation a "cooling off period."