The US Air Force (USAF) has awarded Boeing a contract worth up to $999 million for 27 wing replacements for the service’s Fairchild Republic A-10 Thunderbolt II aircraft, with the option to order 85 more sets over the deal’s 11-year period.

Some 173 aircraft out of the service’s fleet of 283 A-10s already have new wings retrofitted and this contract will cover replacements for the rest, says Boeing. The USAF said in early August that it had just recently finished installing those 173 sets of wings on its A-10s, completing the $1.1 billion Enhanced Wing Assembly replacement programme which started in 2011.

For this latest contract, Boeing will manage the production of up to 112 wing sets and spare kits. Some retrofit work will be performed by Korean Aerospace Industries in South Korea, with the rest done at Hill AFB in Utah.

The USAF introduced the A-10 in 1976 as a close air support aircraft. It is heavily armed, with one 30mm GAU-8/A seven-barrel Gatling gun and up to 7,200kg (16,000lb) of mixed ordnance, according to Boeing.

A-10 production ended in 1984, but the Enhanced Wing Assembly replacement programme was designed to prolong the lifespan of the aircraft into the late 2030s. Wings from that programme are supposed to last for 10,000h of flight before needing a depot inspection.

Work on the latest batch of A-10 wing retrofits is expected to be complete by 23 August 2030, says the USAF. The service says one other manufacturer unsuccessfully bid against Boeing for the contract, though it did not name the company.