ARLINGTON, Va. — The Air Force is planning to cut about 1,400 officers in overmanned career fields with between six and 12 years’ active commissioned service if they do not leave voluntarily by the end of March, officials said.

The move is part of the Air Force’s efforts to cut 40,000 personnel by fiscal 2009, part of fiscal 2007 “force-shaping” plans which call for trimming about 8,000 officers from the rosters by Sept. 29.

As an incentive to convince these officers to leave on their own, the Air Force will double the standard rate of involuntary separation pay for any eligible volunteers, and extended the deadline for that offer through March 31.

The previous deadline had been Jan. 31. So far, about 1,800 officers have taken advantage of the extra separation pay and left voluntarily, officials said.

A top Air Force official said he hopes more officers will take the deal.

“We would rather do voluntarily than involuntarily, but . . . as a planning factor, you have to plan for a reduction in force. It’s just not something you can gin up at the last minute,” Lt. Gen. Roger A. Brady, deputy chief of staff for personnel and manpower, told reporters in December.

“We had a huge surge initially, you know, we probably had more than 1,000 in the first few weeks, and then it’s kind of tapered off.”

The service’s fiscal 2007 reduction goal is 3,200 officers in overstaffed career fields who have six to 12 years in the force. Brady said if the remaining 1,400 officers do not also leave voluntarily, the Air Force will have to hold a reduction-in-force board in June to make the cuts.

The board would take place from June 11 to June 29, and focus on officers in year groups 1995, 1996, 1997, 1998, 2000 and 2001, according to an Air Force message scheduled to be released on Thursday.

“Officers in the 1999 year group, in their primary zone for promotion to major, will not be eligible to meet the board,” the message says. “In addition, no one from the 2002 to 2006 year groups will be eligible for the board even though they may be eligible for VSP [voluntary separation pay] based on their prior enlistment time.”

Airmen chosen by the board will receive only standard involuntarily separation pay and be forced out of the service no later than Jan. 29, 2008.

Troops who take the voluntary separation deal must leave the service by Sept. 29.

Air Force personnel can calculate how much separation pay they are eligible for by using a pay estimator available at: http://ask.afpc.randolph.af.mil.

Brady said the Air Force has no plans to offer further incentives for the officers in the overmanned career fields to leave the service on their own accord, he said.

“You wouldn’t go beyond that amount until you get to people that are, you know, 15-, 16-, 17-year group people,” he said.

Next fiscal year, the Air Force could expand its program to trim its ranks to include officers with between six and 20 years’ experience, he said.

According to Air Force senior leadership, force shaping is the Air Force’s response to its struggle — like all of the services — to balance the rising costs of personnel against its desire to modernize the force to meet future threats.

In fiscal 2007, the Air Force plans to cut its total force from 347,624 personnel to 334,200. Most of those direct cuts are officers.

Enlisted personnel are comparatively safe from the chopping block, but 1,227 noncommissioned officers are being given the choice of either switching career fields or getting out of the service.

Only 2,000 of those losing their jobs under the force-shaping program will be civilians, Air Force officials have said.