Air Canada won't just be AAR Aircraft Services' first customer at its new aircraft maintenance base in Duluth.

It may be its only customer.

That's because maintaining Canada's largest airline's fleet of 89 Airbus A320-series jets will bring the base to full capacity within a year, using four lines of maintenance and employing up to 225 workers in good-paying jobs.

Although the News Tribune first reported a week ago that Air Canada would be AAR's launch customer in Duluth, AAR has since made it official, announcing that it has signed a letter of intent with Air Canada.

According to the letter of intent, AAR will provide Air Canada's A320 aircraft with airframe maintenance services through September 2017.

Air Canada and AAR are finalizing the terms of the five-year contract, said Chris Mason, an AAR spokesman.

AAR -- a leading provider of aircraft maintenance services to airlines -- already is servicing Air Canada's Airbus planes at its Miami maintenance, repair and overhaul base. But the work will be transitioned to the new Duluth base during the next year, with the first line up and running by December.

So far, about 40 of the 60 skilled aviation workers needed to operate the first line have been hired, with more inspectors and structural mechanics being sought. Each line will perform heavy maintenance checks on one plane at a time, a job that can take 15 to 45 days, Mason said.

"Right now our focus for Duluth is squarely on Air Canada and transitioning the line of maintenance from Miami to Duluth," he said.

Based in Montreal, Air Canada is the world 15th-largest commercial airline. It provides passenger service to 59 Canadian cities, 56 U.S. destinations and 63 other cities around the world.

The city of Duluth and AAR announced in April that AAR would move into the city-owned former Northwest Airlines maintenance base. At that time, AAR, based in Illinois, was talking to several potential customers for the new base, Mason said.

As talks with Air Canada progressed, its officials considered several AAR maintenance base locations and paid Duluth a visit last summer, said Brian Hanson, CEO of Area Partnership for Economic Expansion in Duluth, who helped sell both AAR and Air Canada on Duluth.

Besides Miami, AAR also has bases in Indianapolis, Oklahoma City and Hot Springs, Ark.

"The folks at Air Canada were impressed with the Duluth facility," Hanson said. "When they came to see it, it really made a difference to them to hear from our team. We told them about our labor pool. They had a lot of questions. They were pleased with our answers. They got here skeptical and left here impressed."

Mason and Hanson said the fact that the base was built and designed to service an Airbus fleet helped sway Air Canada.

"It made it an excellent fit," Mason said. "The existing equipment in the facility being conducive to Airbus A320 was a factor as well as a talented labor pool."

Hanson said Duluth's proximity to Canada was probably less a factor.

"That could have had something to do with it, but they travel all over the country," he said.

The 188,000-square-foot maintenance base, built for Northwest Airlines in the early 1990s, was vacated by the airline in 2005. Cirrus Aircraft leased space there for a few years, but it had been largely vacant since 2009. Last year, city officials and local economic development proponents stepped up their efforts to find a similar use for the facility, first approaching AAR at an industry expo.