Although Navy, Army and Air Force in the Washington area are facing major job cuts, insiders say the Pentagon is weeks away from coming up with the hard data needed to justify and begin a limited "early-out" retirement program.

The Civil Service Commission has approved early retirement for eligible, senior civil servants in the Office of the Secretary of Defense here. Under the early-out - which CSC must able to retire on immediate pensions at any age after 25 years of service, or at age 50 with 20 years of service. They must take a reduction for each month under age 55, but they do qualify for immediate annuities under the special voluntary early-out program.

The early-out endorsed for OSD covers only a handful of the civilians here who work for Defense. Navy has 36,000 employees; Army 26,000 and Air Force about 7,000 civilian workers. Other Defense agencies bring the total number of Pentagon-related civil servants to just over 83,000.

All the services anticipate cutbacks that must be made by next February. They agree that the cuts apparently can't be handled through normal attrition. That means that many young workers with short service would be hit with layoff notices unless Defense can give older workers an incentive to retire.

Many senior Defense aides would like nothing better than the option to retire early. That isn't going to happen until Army, Navy and Air Force can assess the impact of the cuts, and come up with the data they need to persuade the Civil Service Commission that an early-out is justified. Best advice for people hoping to take advantage of the early-out option is - don't hold your breath.