LONG BEACH >> Boeing will end production of the C-17 Globemaster III about three months sooner than previously expected, meaning California’s final remaining aircraft production plant will shut down in mid-2015.

Boeing announced the revised timeline Monday, saying the change of plans was the result of current market trends and anticipated orders for the four-engine aircraft, which is capable of carrying an M-1 Abrams battle tank and has been in service with the Air Force since 1991.

A spokeswoman said there will be three fewer C-17’s produced than the company had indicated, as orders hadn’t been committed, since the announcement in September of its intention to close the plant, first projected to happen toward the end of 2015. The news came shortly after the aerospace giant delivered its 223rd Globemaster to the Air Force. The company had also marketed the C-17 to the militaries of other nations, such as the United Kingdom, Canada, Australia and India.

At present, Boeing and the union that represents many of the employees assigned to C-17 manufacturing are in negotiations to shape the futures of those people whose livelihoods will be affected by the end of C-17 production. Roughly 2,200 Boeing employees work on Globemaster-related assignments in California.

“Basically, we just roll with the punches,” Stan Klemchuk, president of the United Aerospace Workers Local 148, said Monday.

Negotiations may enable some employees who have worked on the C-17 to continue working for Boeing, although those who do not have to look for a new employer may have to find a new place to live. One possibility for workers, Klemchuck said, is that employees may be able to obtain jobs building the twin-engine 777X passenger jet in Washington state.

Although there is hope that C-17 employees will remain with Boeing, Klemchuk acknowledged that the news has some of the union’s members feeling down.

“It’s very disheartening right now, because most of my members are in their 50s, early 60s,” he said. “It’s hard enough for a person these days right out of college to get a job right now.”

Boeing is set to begin production of the 777X in 2017. The tantalizing prospect of the 777X being built in Long Beach seemed to be a possibility late last year, but Boeing and labor groups reached an agreement in January to keep 777X production in the Evergreen State.

Boeing’s C-17 plant is near Long Beach Airport, and the massive gray aircraft can occasionally be seen flying over the city. The end of C-17 production will not mean that all C-17-related work will cease since Boeing has contracts to sustain and modernize aircraft that are already in use, spokeswoman Cindy Anderson said.

Anderson did not provide an estimate of how many employees might be laid off once production ends. She said the company is attempting to mitigate the effects on its labor force through retirements and attrition.

In addition to Long Beach, Boeing has presences in Seal Beach, Huntington Beach and El Segundo. The company employes about 19,000 workers in the state.

Boeing has not decided what will become of the company’s C-17 plant. Land where the aircraft manufacturer once assembled the 717 passenger aircraft is being transformed into a commercial development called Douglas Park.

The future of Douglas Park is likely to be much different from its past. Boeing has sold nearly 200 acres of land to Irvine real estate firm Sares Regis Group, and that company has taken steps to reinvent the area as a business center.

Sares Regis Group has signed a 15-year lease with luxury automaker Mercedes-Benz, setting the state for the firm to establish its western regional offices at Douglas Park.

Additionally, Long Beach-based Urbana Development and two doctors’ groups broke ground last month on twin medical offices that are expected to open at Douglas Park early next year.

Whoever serves as Long Beach’s next mayor — the primary election is Tuesday­— needs to sit down with Boeing and work on planning for how to reinvent the C-17 plant, said Long Beach Area Chamber of Commerce CEO Randy Gordon.

“We knew that it was going to end at some point,” he said. “It’s been a great ride.

“That’s the last piece of priceless real estate that we have,” Gordon added. “We’ve got to make sure that we have high-paying jobs at that location.”

Contact Andrew Edwards at 562-499-1305.

A story in Tuesday’s paper misstated that three Boeing Co. C-17 orders were canceled since the company’s announcement in September of its intention to close the plant. A spokeswoman said that those three planes did not have committed orders.