More than 100 Defense Department workers scheduled for pre-Christmas layoffs have been given an extra month to find new jobs.

The introduction to unemployment is only the first step in a Pentagon reduction ordered by Defense Secretary Harold Brown. About 400 employees will be affected by the RIF (reduction-in-force), which involves 105 people actually going out the door, and 113 grade demotions.

Because of the "bumping" procedures involved in any federal RIF, many employees will be moved around as more senior workers exercise their retention rights by moving laterally, or down, to other jobs.

Army, Navy and Air Force headquarters units here are also under orders to cut their staffs by 21 to 25 per cent.

In some cases the reductions can be made on paper. That involves transferring the jobs of units and offices from "headquarters" functions - which are under the gun to cut back - to field operations, which are not. In those paper changes, employees will wind up working in the same offices, at the same jobs and same pay, but will no longer be part of the headquarters. Their removal from headquarter charts, however, will count toward the reduction.

For many Defense workers, however, the cuts are very real. Defense is making efforts to find new jobs for employees. But the government job market is tight and turnover - through resignations and retirement - is down.

For the 105 Defense civilians, the "notice of separation due to reduction-in-force" came with all the dread of a midnight telegram. It arrived earlier this month and reads as follows: "A decrease in civilian manning authorizations with Office Secretary of Defense/Joint Chiefs of Staff has resulted in the abolishment of positions. It is regretted that your position must be offered to another employee with higher retention rights." In industry, it would read: "You're fired."

People getting RIF notices in that batch were told they were to be separated by Dec. 14. They were also told they could be granted leave-without pay "for such additional time as necessary to provide you with a 90 day notice period." All heart, those people.

Maybe somebody pointed out that Dec. 14 is just before Christmas, a traditionally bad time to fire people. At any rate, Defense yesterday issued new letters, saying the folks could hang around and draw their checks thorugh Jan. 14. Better than nothing. But just barely.

Responding to yesterday's column here - which quoted heavily from Jimmy Carter's pledge that nobody would be downgraded or fired because of reorganization - Defense had to to say:

This really isn't a reorganization, certainly not a presidential reorganization. Therefore, the President's nobody gets hurt promise doesn't apply. What this is, the Pentagon says, is an "ordinary management action by a department head (the Secretary of Defense)" to provide for more efficient operations.