NORTH BERWICK – Pratt & Whitney is eliminating 91 jobs at its aircraft engine plant here, the result of a continuing slump in the aviation industry.

Twenty full-time employees accepted voluntary severance packages while 49 full-time workers and 22 part-timers are being laid off, said Dan Coulom, manager of public relations for Pratt & Whitney’s corporate parent, United Technologies.

The layoffs, which take effect Jan. 31, “are pretty much across the board” in all departments, Coulom said.

The drop in the number of commercial airline passengers, fueled by the terrorist attacks of Sept. 11, 2001, has cut demand by airlines for new planes, the spokesman said.

“It’s based on what we know about the economy,” Coulom said. “It’s continued to slump, and so has the industry.”

In October, Pratt & Whitney announced it was cutting its work force worldwide by 2,500, according to Coulom. “This is part of the 2,500,” he said.

Since 2001, 700 employees have been cut from the work force at the East Hartford, Conn., plant, Coulom said. Further reductions have come at plants in Canada.

Other facets of Pratt & Whitneys operation, including the manufacture of military, commuter and cargo plane engines and rocket engines, are not affected, Coulom said.

Pratt & Whitney, based in Hartford, Conn., employs about 34,000 worldwide, including about 1,400 who will remain on the job at North Berwick.

The announcement Tuesday was the latest blow for Maine’s manufacturing sector, which was rocked this month by the Chapter 11 bankruptcy filing by Great Northern Paper Inc. that raised questions as to when and if its mills at Millinocket and East Millinocket would reopen.