Work performed by some active-duty U.S. Air Force maintenance units will be temporarily transferred to contractors.

The move to contract maintenance for some legacy non-deployable flying units begins in fiscal year 2017 and will continue through 2020.

The Air Force said it will allow for cross-training of about 1,100 experienced maintainers from legacy aircraft -- F-16 Fighting Falcons, A-10 Thunderbolt IIs, and C-130 Hercules -- into the F-35 Lightning II program.

"There is currently a shortfall of 4,000 maintainers as a result of budgetary constraints that has significantly impacted our overall maintenance manning," said Lt. Gen. John B. Cooper, the deputy chief of staff for logistics, engineering and force protection.

"Changes in the geopolitical environment also require us to maintain our current fleet, rather than divest legacy aircraft," Cooper said. "All of this has affected our plan to transition maintenance manpower from legacy aircraft to the F-35A as originally planned."

Cooper said the temporary transition is a temporary move. "This is one of many deliberate measures we are taking to help manage this shortage of experienced aircraft maintainers until we can grow and develop our new accessions," he said.

Other initiatives to manage the maintainer shortage include: increasing the number of maintenance accessions; offering selective re-enlistment bonuses; and offering former maintenance airmen the opportunity to return to active duty.

The Air Force said some units and locations affected by the change include: formal training units at Davis Monthan Air Force Base, Ariz., and at Little Rock AFB, Ark.; A-10 Weapons Instructor Course and operational test and evaluation units at Nellis AFB, Nev.; F-16 aggressor maintenance at Eielson AFB in Alaska; aerospace ground equipment units at Anderson AFB, Guam; Holloman AFB and Kirtland AFB in New Mexico; and Peterson AFB in Colorado.