Lockheed Martin’s Sikorsky helicopter facility in Coatesville will shut down by the end of this year, a company spokesperson confirmed Thursday.

Callie Ferrari, in a statement, announced that Lockheed Martin “has made the difficult decision to close the Coatesville, Pennsylvania, facility by year-end and relocate production to other Sikorsky sites due to the multi-year slump in the rotorcraft industry and the need to balance footprint and workforce with customer and requirements.”

The closure of the Chester County plant will affect about 465 employees. The plant workforce was notified Wednesday of the plans to close the facility.

“We are working to place as many of these employees as possible in other Lockheed Martin facilities,” said Ferrari.

That will include about 75 positions, including engineering and functional roles, that will relocate to Lockheed Martin’s King of Prussia facility to continue to support Sikorsky operations, she said. About 70 positions will be established in the company’s Owego, N.Y., facility.

The timeline for personnel moves will be assessed over the next 30 days, Ferrari said in an email. The plant’s workforce is nonunion, she said.

The decision to close the plant, she said, “was made due to the prolonged downturn in the global helicopter market, and Sikorsky’s need to balance footprint and workforce with customer and market requirements.”

Completion work on Sikorsky’s S-92 and S-76D helicopters will occur in the Owego facility. The craft are largely used in commercial off-shore oil operations. The plant also performed modifications and upgrades for the Canadian Maritime Helicopter Program aircraft.

Sikorsky’s Coatesville campus, at 110 Stewart-Huston Dr., has three buildings, two of which are leased and a third called the Heliplex, which Lockheed owns and will put up for sale, Ferrari said in an email.

“We have informed the landlords of the other two buildings that we will not renew the leases when they expire in August and December, respectively, of this year,” she said.

In 2015, Lockheed Martin announced that it planned to purchase Sikorsky Aircraft Corp. for $9 billion, a deal that was completed later that year. At the time, Lockheed CEO Marillyn Hewson said she saw “a real opportunity for growth” in Sikorsky’s commercial division based in Coatesville. At the time, 75 percent of Sikorsky’s business was military and 25 percent commercial.