ARLINGTON, Va. — The Air Force is changing its Air and Space Expeditionary Force policy to provide increased predictability for the nearly half of deployed airmen whose deployments aren’t working out the way the system was designed.

The improvements to the AEF system won’t make the deployments shorter or less frequent, according to Col. J.R. Reid, director of the Air Force’s War and Mobilization Planning Policy Division, which oversees AEF policy.

Instead, according to one of Reid’s deputies, Maj. Leslie Higer, the changes are designed to eliminate the nagging question airmen ask themselves when they are home: " ‘I knew they came early for me last time, and I know they’ll come early for me this time — but when?’ "

One of the reasons the Air Force decided to adopt the AEF in the late 1990s was so that airmen would know exactly when they would be vulnerable for deployment, and how long they would be gone, Reid said.

The AEF works on a 20-month cycle, and divides the active Air Force into 12 "buckets." At any one time, two of these buckets are either vulnerable to deploy, or actually rotated into theater for 120 days. Then they come home and are not vulnerable to deploy again for 16 months.

But the wars in Iraq and Afghanistan have busted that cycle for thousands of airmen in high-demand jobs, who are getting pulled out of their AEF buckets long before they are supposed to be deployable, Reid said.

In fact, out of the 35,000 airmen who are currently deployed around the world, "45 percent are deployed outside of the tempo of the AEF," according to Reid.

The Air Force can do nothing to change the deployment tempo for its personnel, Reid said.

But what leaders can, and should do, Reid said, is redesign the system to "reflect the reality of the tempo … so airmen can realistically schedule" events such as schools, tests and moves.

"How often and how long don’t change," Reid said. "But I’ll give you a better understanding of when" an airman will deploy.

The new AEF system splits the force into five tempo-based "bands."

About half the Air Force will stay in their buckets in their normal AEF cycle (which will also be called Band A), with a 1:4 dwell.

But the other half will be sorted into the other four bands, each one containing a list of specific functions.

Some of those have been decided: for example, Band "D" will include vehicle operations, vehicle maintenance, port operations, aerial readiness, among others, Hilger said.

But Air Force leaders are still sorting out which functional areas to put into which bands, a task that will determine which airmen are going to be part of the "tempo" system and which ones will stay with the original AEF construct, Reid said.

Meanwhile, each of the four bands will have its own dwell ratio: 1:1, 1:2, 1:3, or 1:4, based on six-month increments.

The busiest band, Band E, has a 1:1 dwell, meaning six months vulnerable to deployment or actually deployed, then six months at home station before starting all over again.

The goal is to finish sorting airmen into their bands by Oct. 1, Reid said, and to begin using the new system to actually deploy people by Jan. 1.