The service on Friday ordered a temporary stand-down of 13 out of 104 F-35s in the fleet "due to the discovery of peeling and crumbling insulation in avionics cooling lines inside the fuel tanks," according to a statement at the time.
Two additional aircraft, belonging to Norway and currently stationed at Luke Air Force Base, Arizona, have also been affected.
Lt. Gen. Christopher Bogdan, executive officer for the F-35 Lightning II Joint Program Office, on Tuesday said maintenance crews will begin additional repairs next week on the grounded aircraft.
"Now is the time to find this and fix them," he said during a panel at the annual Air Force Association's Air, Space & Cyber conference in National Harbor, Maryland. "It affects only 15 model A airplanes, and if this problem were not to be found today -- but three or four years from now -- we [would have had] hundreds of airplanes out there affected."
Officials called the F-35 program a global initiative, with more than eight partner countries acquiring the plane. The latest is Israel, which will receive its first two A models in December, Bogdan said. "You find things early, you fix them, you make the airplane better, you make the weapons system better, and you move on," he said.
Gen. Herbert "Hawk" Carlisle, commander of Air Combat Command, took aim at the aircraft's critics when he said there are people "who will make comments, but will never actually have to do anything." As far as he was concerned, Carlisle said, "If a [combatant commander] called me up and said, 'I need these attributes' and the F-35 fits, I would send it tomorrow. No doubt in my mind."
The Joint Strike Fighter developed by Lockheed Martin Corp. last month surpassed a milestone when officials declared the stealth jet initial operating capability.
The cost of the program has reached nearly $400 billion for more than 2,400 planes. The Air Force plans to buy 1,763 F-35As over 20 years.
In a separate briefing earlier in the day, Carlisle said the service has recently halved the number of squadrons expected to be in place in the next decade.
"A lot of things have changed since but in 2010 [we estimated] by the year 2028 we were going to have 32 F-35 squadrons. But in the 2016 budget [we estimate] by the year 2028 we will only have 14 … that's a pretty drastic reduction."
The service also aims to do more with less driven in part by the higher operations tempo. In the air war against the Islamic State of Iraq and Syria, or ISIS, "more than 60 percent" of operations weighs on the Air Force, the general said.
The Air Force should have more information on the status of the grounded F-35s "by the end of this week," Carlisle said.
The aircraft at Hill Air Force Base in Utah "were the ones with the biggest impact to airplanes already out in the field," he said, referring to the grounding. "We've had several conversations with Lockheed Martin … and we believe there is a way forward."
Carlisle added this "is not a design problem … it's not a developmental problem. It is a subcontractor that failed to perform to standards." He said the flaw "is very contained."
Neither Carlisle nor Bogdan would comment on which contractor is supplying the cooling lines, but Bogdan said the Air Force will use the same company going forward.