Air Canada is encouraging global aircraft repair companies to fill the void of insolvent Aveos Fleet Performance and hire its former workers across the country.

To help address its long-term needs for heavy maintenance, Canada's largest airline is encouraging companies to "conduct due diligence and assess which of the former Aveos businesses may be viable in Canada under new ownership."

Alan Butterfield, vice-president maintenance and engineering, said Air Canada has "a strong preference" to work with companies that provide services in Montreal, Winnipeg, Vancouver and Toronto.

"There exists a pool of well-trained, qualified and talented people available in these cities," he said Thursday. Air Canada, which has launched a request for proposals, said it will favour repair and overhaul companies with "globally competitive cost structures" that have or will establish "some portion of their operation in one or more of these cities employing the skills of Canadian aviation technicians."

"The company expects to work collaboratively with governments and other stakeholders towards viable long-term arrangements that are cost competitive," he added.

The comments by Air Canada came as Aveos workers protested for a fourth day.

Police were called to Air Canada's headquarters in Montreal after about 100 former Aveos workers blocked traffic and delayed a bus carried airline workers.

The Montreal-based airline has said it is making alternative short-term arrangements following this week's sudden closure of Aveos facilities and the lay off of about 2,600 workers.

The airline's own 2,300 mechanics are doing day-to-day maintenance while three planes have been sent to Quebec company Premier Aviation in Trois-Rivieres. It is also working to complete repair and maintenance on three widebody planes stuck in Aveos facilities in Montreal and Vancouver.

Charest threatened to sue Ottawa, Air Canada

The moves will eliminate any impact of Aveos' closure on passengers, the airline said.

Aveos blamed Air Canada for its financial troubles, saying in a court filing that the airline reduced, deferred, and cancelled maintenance work, which resulted in approximately $16 million in lost revenue in less than two months.

Aveos announced last weekend it was shutting down three main plants in Vancouver, Winnipeg and Montreal, as well as other facilities in Edmonton, Calgary, Trenton and Mississauga, Ont.

Quebec Premier Jean Charest has threatened to sue the federal government and Air Canada by ensuring maintenance work remains in the country.

It was assessing terms of legislation that transformed Air Canada from a Crown corporation into a private company in 1988.

Air Canada insists it is in "full compliance" with all aspects of the Air Canada Public Participation Act by maintaining overhaul centres in Winnipeg, Montreal and Mississauga, Ont. "

We intend to remain be fully compliant with the Act, which also requires we maintain our head office in Montreal," spokeswoman Isabelle Arthur said in an email.

The airline said Ontario Superior Court Justice Frank Newbould ruled last May that it met the Act's requirements by having its own overhaul and maintenance operations.

"We are satisfied that the current circumstances do not change that finding," she added.