About 1,100 airmen, including part of a squadron of A-10 close-air-support jets, will be deployed from Davis-Monthan Air Force Base by mid-March.

It’s one of the biggest near-simultaneous deployments from the Tucson base in memory.

The deployment — which comes as the Pentagon is seeking to retire the A-10 Thunderbolt II fleet — represents a trifecta of D-M’s biggest flying units, including part of the 354th Fighter Squadron with A-10s and associated maintenance and support units, combat-rescue elements of the 563rd Rescue Group and units of the 55th Electronic Combat Group.

The Air Force isn’t saying exactly where each unit is headed, citing security concerns. The units are being deployed around the world including to the U.S. Central Command, or CENTCOM, whose area of responsibility includes the Middle East, North Africa and Central Asia, most notably Afghanistan and Iraq, a D-M official said.

About 400 airman are scheduled to deploy in the next week or two, followed by rest through mid-March, said D-M spokeswoman Lt. Erin Ranaweera.

“All these deployments are not necessarily related, but they’re all leaving at about the same time,” said Ranaweera, adding that the typical deployment period is six months.

While it’s not unusual for hundreds of D-M airmen to deploy at once, the timing and scope of the multiple deployment will create some challenges on the base, Ranaweera said.

For example, the deployment includes elements of the 355th Mission Support Group that handle everything from security and contracting to vital behind-the-scenes paperwork like processing personnel orders and travel documents, Ranaweera said.

As a result, many airmen will have to be trained to fill in, some base office hours will be curtailed and one gym facility will be temporarily closed, she said.

“It’s going to create a pretty massive hole, and people are going to have to work pretty hard, taking care of those positions and taking care of the families and all that,” Ranaweera said.

The head of a local group that supports D-M called on the community to support the families of deployed airmen.

“It’s pretty significant in terms of its impact on the base,” said Brian Harpel, president of the DM50.

Harpel said the large, multi-unit deployment shows the importance of D-M’s mission-support units as well as its front-line combat units.

“We’ve got a lot of platforms here, but it’s not just the flying missions that are important,” Harpel said.

D-M flying units have been routinely deployed over the past several years.

Part of the 354th Fighter Squadron — known as the Bulldogs — returned to D-M from an overseas deployment last April. Besides the 354th, D-M hosts two A-10 training squadrons. Each full squadron has about 25 planes.

The 563rd Rescue Group includes units operating HH-60G Pave Hawk rescue helicopters and HC-130 Combat King transport and aerial refueling planes, and two squadrons of pararescuemen.

Next week, members of the 305th Reserve Rescue Squadron, part of the Air Force Reserve 943rd Rescue Group, will be returning to D-M from a six-month deployment to Djibouti in support of Operation Enduring Freedom.

The 55th Electronic Combat Group includes units that operate and maintain EC-130H Compass Call electronic surveillance and jamming aircraft.

The DM50’s Harpel said the latest deployment of A-10s and the EC-130 electronic-combat planes seem to contradict the Pentagon’s plans to retire the A-10 “Warthog” fleet and cut back the EC-130 fleet.

The Pentagon, in its fiscal 2015 budget plan, proposed retiring the entire fleet of more than 280 A-10s — more than a third of which are based at D-M — to save more than $4 billion. While acknowledging the value of the A-10 in supporting ground troops, the Air Force says it can’t afford to keep the Warthog fleet.

Congress pushed backed, passing a defense bill that saves most of the A-10 fleet for a year while allowing the Air Force to put 36 Warthogs in backup flying status. The Air Force also has proposed cutting the fleet of EC-130s at D-M by seven aircraft, about half the total, in fiscal 2016.

Harpel noted that units of D-M’s electronic combat group have been continuously deployed since 2001.

“It’s very counterintuitive, what’s going on here,” Harpel said, calling the budget battle a “tug of war” between Congress and the Air Force.

At least one other A-10 squadron has been deployed to the CENTCOM region since the U.S. and its allies began battling Islamic State militants last summer. An A-10 squadron from the Indiana Air National Guard 122nd Fighter Wing was sent to the region starting in September.

Air Force Secretary Deborah Lee James said in mid-January that the A-10 has been flown in 11 percent of the sorties against Islamic State targets.

Contact Assistant Business Editor David Wichner at 573-4181 or dwichner@tucson.com.