(Calgary) The union representing WestJet maintenance engineers says its members voted overwhelmingly to reject a tentative agreement with the airline.

The Aircraft Mechanics Fraternal Association, which represents some 670 aircraft maintenance engineers and other specialized positions at the carrier, says about 97 percent of its members voted against the deal.

WestJet says the result has “no impact on operations,” but company president Diederik Pen called the outcome “very concerning.”

Pen contends the deal would have made the employees the highest-paid aircraft maintenance engineers in the country after “difficult” negotiations for their first collective agreement.

The union cited wages, outsourcing, hours and layoff protection as central issues in the bargaining process.

The two sides reached a tentative agreement on May 6, two days after WestJet issued a 72-hour lockout notice to maintenance engineers following their announcement of a strike vote.