Enlarge / KANDAHAR, Afghanistan (May 21, 2018)—Two US Air Force A-10 Thunderbolt IIs, assigned to the 163rd Fighter Squadron, begin to taxi on the flightline at Kandahar Airfield, Afghanistan, May 21, 2018. Many A-10s are reaching the flight-hour limits of their wings; the Air Force is now launching a procurement program to buy 112 new sets. (US Air Force Photo by Staff Sgt. Corey Hook) (credit: US Air Force)

The US Air Force has finally issued an official request for proposals for a program to manufacture new wings for its aging A-10 Thunderbolt attack aircraft. The deadline for proposals from would-be contractors is August 23. But the program will likely not be started before some of the Air Force’s older A-10s have to be grounded, as a previous wing-replacement program (awarded to Boeing) has reached its end.

The program, called the A-10 Thunderbolt Advanced Continuation Kit (abbreviated as ATTACK), builds upon the previous Wing Replacement Program, which upgraded 173 A-10 aircraft between 2007 and 2016. ATTACK will deliver a maximum of 112 pairs of wings and associated parts over a five-year ordering period, following an initial delivery of three wing sets to verify quality of work. The Air Force will install the new wings at its A-10 depot at the Ogden Air Logistics Center in Utah.

The statement of work will require whoever wins the contract to develop their own 3D models of the wing sets, flaps, and other parts from the Air Force’s specifications. This may give Boeing a slight edge, since the company has already done most of this work and has demonstrated an ability to deliver the wings. But it’s not clear yet if Boeing will bid on the new program, which is slightly smaller and shorter in duration than the original re-wing program.