The union representing Air Canada's flight attendants says it is "profoundly" disappointed by an arbitrator's decision released Monday.

Canada Industrial Relations Board arbitrator Elizabeth MacPherson endorsed Air Canada's position that the provisions be imposed without alteration.

The new four-year deal expires March 31, 2015.

More than 65 per cent of employees who voted rejected the original agreement even though it had been unanimously recommended by the union's bargaining committee.

That was the second tentative contract the flight attendants had rejected. They were on the verge of going on strike when Labour Minister Lisa Raitt referred the matter to the CIRB last month.

"Flight attendants deserve better than this decision,” Paul Moist, national president of CUPE, the attendants’ union, said in a release.

“They deserve better treatment from Air Canada, and they certainly deserve better from their federal government," said Moist.

"This government has been extremely irresponsible, and it's their constant interference in collective bargaining that tipped the scales in favour of the company and against hardworking flight attendants."

But MacPherson said the union won improvements in the second tentative agreement that was unanimously recommended by its bargaining committee.

Union bargainers did 'superb job'

"An objective comparison of the two tentative agreements reveals that the union bargaining committee did a superb job of extracting additional concessions from Air Canada," she wrote in the 12-page ruling.

MacPherson said her decision most closely resembled what would have been achieved had the case not been referred to an arbitrator by the federal government and instead been allowed to run its course through collective bargaining — including the right to a strike or lockout.

Air Canada chief operating officer Duncan Dee said in a release the airline was "pleased with this final and binding decision to implement the terms of the second tentative agreement that was reached with CUPE's democratically-elected leadership in September."

"The implementation of a new collective agreement with our flight attendants ends a period of uncertainty for our customers and will allow Air Canada and its employees to move forward together."

The dispute centred on the airline’s aim to start a low-cost carrier, wages, working conditions and pensions. Both sides had agreed that the ruling would be final and binding.

The union said it submitted to arbitration only “under [the] threat of back-to-work legislation and after two unwarranted referrals to the Canada Industrial Relations Board by … Raitt.”

In the ruling, MacPherson said the airline argued the second tentative deal was a fair and equitable settlement that was not impeded by the threat of government intervention. In it, the employer offered increased meal allowances and agreed to a hybrid pension system for new hires.

Outcome said to be 'fair'

It also withdrew demands for provisions related to a low-cost carrier and variable scheduling that would have provided the flexibility it had hoped to achieve.

After the deal was negotiated, local union president Jeff Taylor said negotiators achieved 80 per cent of what members wanted.

Despite the union outcry against the ruling, labour specialists said it makes sense.

"It actually sounds like a fair outcome," said George Smith, a fellow at Queen's University and former director of employee relations at Air Canada.

Ian Lee, a professor of strategic management at Carleton University, said MacPherson made a very compelling argument that is unlikely to rouse anger by union members.

"I couldn't see them imposing a more generous settlement on Air Canada and the union because it could have literally pushed [the airline] over the edge," he said in an interview.

With files from The Canadian Press