Supersonic speeds could cause big problems for the F-35′s stealth coating

At extremely high altitudes, the U.S. Navy and Marine Corps’ versions of the F-35 jet [The $100 million-plus plane] can only fly at supersonic speeds for short bursts of time before there is a risk of structural damage and loss of stealth capability, a problem that may make it impossible for the Navy’s F-35C to conduct supersonic intercepts.

The Defense Department does not intend to field a fix for the problem, which influences not only the F-35’s airframe and the low-observable coating that keeps it stealthy, but also the myriad antennas located on the back of the plane that are currently vulnerable to damage, according to documents exclusively obtained by Defense News.

The F-35 Joint Program Office has classified the issues for the "B" and "C" models as separate category 1 deficiencies, indicating in one document that the problem presents a challenge to accomplishing one of the key missions of the fighter jet. In this scale, category 1 represents the most serious type of deficiency.

Both deficiencies were first observed in late 2011 following flutter tests where the F-35B and F-35C both flew at speeds of Mach 1.3 and Mach 1.4. During a post-flight inspection in November 2011, it was discovered the F-35B sustained “bubbling [and] blistering” of the stealth coating on both the right and left sides of the horizontal tail and the tail boom.

During similar tests of the F-35C in December 2011, “thermal damage” that compromised the structural integrity of the inboard horizontal tail and tail boom were apparent.

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