The U.S. military's growing fleet of F-35 stealth fighters will fall short of the 80 percent readiness goal that former Defense Secretary James Mattis instituted before quitting in protest of President Donald Trump's foreign policy in January 2019.
Former Secretary of the Army Mark Esper, who is Trump's nominee to replace Mattis, in mid-July 2019 told a Senate committee the roughly 300-strong fleet of F-35s belonging to the U.S. Air Force, Navy, and Marine Corps "is not expected" to meet Mattis's readiness goal.
Esper blamed the F-35's canopy, or "transparency." "Transparency supply shortages continue to be the main obstacle to achieving this," Esper told the committee. "We are seeking additional sources to fix unserviceable canopies."
The Government Accountability Office highlighted the canopy shortage in an April 2019 report. The F-35's canopy, which features a special coating that reflects radar waves and prevents them from bouncing off the inside of the cockpit — a potentially major source of radar returns — "failed more frequently than expected," the GAO pointed out.
Lockheed Martin, which builds the F-35, searched for an additional subcontractor to help boost canopy-production, the GAO reported.
The F-35 isn't the only warplane to fall short of the readiness goal. Mattis directed all Air Force, Navy, and Marine Corps F-15, F-16, F/A-18, F-22, and F-35 squadrons to achieve an 80 percent mission-capable rate by the end of September 2019.