Half of the temporarily grounded F-35A fleet will be flying again by the end of the week.
In a statement, the USAF Hill Air Base Wing Public Affairs office said two of the 10 previously grounded aircraft began flying again last week.
Three more jets are scheduled to be authorised for flight today.
The US Air Force grounded the jets in September, a few weeks after maintenance crews at Hill Air Force Base discovered “peeling and crumbling” of the avionic cooling line insulation inside one of the F-35As fuel tanks.
An investigation was launched after the initial discovery, and eight other jets were also found to have the issue. According to the public affairs office release, the jet repairs are being performed at Hill.
In August 2016 the US Air Force declared the F-35A basic combat ready.
The 34th Fighter Squadron located at Hill Air Force Base, Utah, has at least 12 combat-ready jets capable of global deployment. F-35A is scheduled to be full combat ready in 2017 with its 3F software upgrade.
Air Combat Command will initially deploy F-35A to Red Flag exercises and as a “theatre security package” to Europe and the Asia-Pacific. The jet will probably not be fighting Islamic State in the Middle East earlier than 2017.