Job security key issue in Air Canada labor talks

* Mechanics worry jobs could go to El Salvador

* Union may seek extended job security

* Talks seen continuing through weekend

By Susan Taylor

OTTAWA, July 3 (Reuters) - Air Canada's (ACa.TO: Quote, Profile, Research) biggest union may push for additional job security in labor talks with the debt-heavy airline and a federally appointed mediator on Friday, but it doesn't expect a quick resolution.

Senior negotiators from the International Association of Machinists and Aerospace Workers, whose members narrowly rejected a 21-month deal with the carrier this week, are meeting with Canada's biggest airline and mediator James Farley, a union spokesman said.

Mechanics are worried their aircraft maintenance, repair and overhaul work will be transferred to Aveos Fleet Performance Inc in El Salvador, a sister company previously called Air Canada Technical Services that was spun off in 2007.

"What these guys are afraid of is that the work is going to go to this company called Aveos," said IAMAW spokesman Bill Trbovich.

"As it stands now, Aveos does not have the capability to do that work, but there's nothing stopping them from building a hangar to do that. And what we want is assurances that they're not going to take that work out of the country."