The US Air Force (USAF) has placed 18 primary combat-coded A-10 Thunderbolt II close-combat support aircraft into the backup-aircraft inventory (BAI) status.
Congress has authorised an increase a total of 36 A-10 aircraft into BAI status. The service, however mothballed a fewer number of aircraft to assess whether the action adequately balances ongoing requirements and the need for upgrade.
US Air Force secretary Deborah James said: "While we are authorised by Congress to put 36 aircraft into BAI status, doing that now would require taking down an entire squadron.
"Out of respect for the intent of Congress, we’re placing 18 aircraft in BAI status."
US Air Force chief of staff general Mark Welsh said: "We will revisit this action as the year progresses to assess the need to put the additional 18 aircraft into BAI status.
"This action represents the difficult choices required to balance between maintaining the capacity to meet current operational requirements, and the resource investment required to keep our modernisation efforts on schedule."
Of the total 18 aircraft, nine are currently assigned to Davis-Monthan Air Force Base (AFB), Arizona, while Moody AFB, Georgia, and Nellis AFB, Nevada, host six and three aircraft, respectively.
The mothballed A-10s will serve as replacement for unserviceable aircraft.
The BAI conversion is expected to relieve experienced maintainers, enabling them to be integrated into the F-35 Lightning II programme, and will not impact planned A-10 deployments through the end of 2018.
An independent cost assessment and programme evaluation (CAPE) study undertaken in 2015 confirmed that a limited supply of experienced fighter maintenance personnel is constraining legacy fleet readiness and the standup of F-35A squadrons.
The study suggested that the transfer of even the limited number of A-10s to back-up flying status was sufficient to counter current maintenance manning and experience shortfalls.
In an effort to achieve F-35 reaching initial operational capability in August 2016, the USAF plans to transition one of the two F-16 squadrons early at Hill AFB, and also contract some maintenance functions at Luke AFB, Arizona, to meet the F-35 bed down requirements.
Image: A USAF A-10 Thunderbolt II aircraft conducts close-air support training near Davis-Monthan Air Force Base, Arizona, US. Photo: courtesy of Jim Haseltine.