Aerospace industry employment nationally fell during 1988 for the first time in five years and is expected to continue downward this year, according to a recently released industry survey.

Utah's two largest aerospace employers, however, report steady work force levels. And the Mountain States are expected to increase the percentage of workers in aerospace firms by December 1989, according to a survey by the Aerospace Industries Association.The association's annual employment survey released this month shows 1,306,000 people work in the aerospace field. The decline from the year earlier represents a 1.7 percent drop, with an additional 1.2 drop forecast in 1989, the survey said.

Utah's Morton Thiokol has an estimated 8,000 workers in the state with a substantial number of those employed in aerospace. "And we expect very stable employment levels for at least the next five years," Rocky Raab, company spokesman, said Monday.

"We had a substantial increase in employment from '86 to '88 where we grew by about 1,500 people and now that we are going from research and design development back to production, our numbers are down slightly," said Raab.

Thiokol announced last month that about 60 workers would lose their jobs following the completion of the solid rocket motor redesign project ordered in the wake of the shuttle Challenger explosion.

At Hercules Aerospace, "we're doing reasonably well," said company spokesman Jack DeMann. "We're going through a combined reduction of force and hiring."

The company is shifting from development stages in the Delta II and Titan IV rocket programs to production, DeMann said.

"The bottom line is by the time the effort is completed we'll have 75 more workers" in the production and support areas, he said.

Nationally, the military segment of the aircraft business accounted for a decline of 28,000 jobs while the civil sector grew by 3 percent to 241,000. The increase in orders for commercial planes spurred the rise in the civil sectors.

"This decline reflects continued changes in the civil and military sectors of the industry," said Carl Pascale, manager of the industry association's Economic Data Service. "While the overall backlog of unfilled orders grew in 1988, civil products accounted for the majority of the growth for the second consecutive year."

The missiles and space sector declined by 1.4 percent in 1988 and a slight recovery is expected in 1989 as missile and the space station production increase, the survey said.