Less than 48 hours after Lockheed Martin and the Pentagon reached a handshake agreement on the purchase of a whopping 480 F-35 Joint Strike Fighters, an absolute cluster bomb of stories has dropped detailing significant technical issues with the jets. The revelations cover ongoing problems for all three F-35 variants, including performance limitations, troubles when operating in very hot or very cold weather, dangerous cockpit pressure incidents, faults in the helmet-mounted display, serious safety concerns in the event of a blown tire, and much more. The new details underscore the Joint Strike Fighter's ongoing troubles as the Pentagon's central Joint Program Office, or JPO, seeks to move the aircraft out of its developmental phase for good, as well as highlighting a worrying, but long-standing lack of transparency about the state of the program. Defense News dropped the bundle of stories near-simultaneously on June 12, 2019—all of which are well worth reading in full—based on documents that it had obtained detailing 13 remaining Category 1 deficiencies across the F-35A, B, and C variants as of late 2018. These reviews of the issues were reportedly marked unclassified, but "For Official Use Only." Not all of the problems in these reports were previously unknown, but a number of them had never become public and the details about the known issues add important additional context. In total, this also represents what is perhaps the first full public accounting of so-called unclassified "CAT 1" problems across the Joint Strike Fighter program at any one point in time. Keep in mind there are also throngs of other deficiencies still in play that are serious, but don't rise to the CAT-1 level, at least not at this time.

“CAT 1-As are loss of life, potential loss of life, loss of material aircraft," U.S. Navy Vice Admiral Mathias Winter, the current head of the F-35 JPO, said in defense of the program in an interview with Defense News. "Those have to be adjudicated, have to be corrected within hours, days. We have no CAT 1-A deficiencies." The remaining problems are "CAT 1-B," which “have a mission impact with a current workaround that’s acceptable to the warfighter with the knowledge that we will be able to correct that deficiency at some future time,” Winter continued. The F-35 program's top officer said that nine of the 13 deficiencies Defense News reported on are on track to get fixed before the Pentagon makes a decision to proceed with full-rate production of the jets, set to occur later this year, while software fixes down the road are expected to solve two more.

Lockheed Martin From left to right, the F-35C, the F-35B, and the F-35A.

USMC A US Marine Corps F-35B.

The limitations on afterburner flight above Mach 1.2 are also highly concerning and the workarounds that are officially in place now seem all but impossible to realistically implement. F-35Bs cannot fly at Mach 1.2 for more than 80 total seconds throughout the course of a mission before needing to slow down for at least three minutes. At Mach 1.3 or above, the B model risks structural damage after just 40 cumulative seconds. The F-35C does not have a restriction at Mach 1.2, but can't fly for more than 50 cumulative seconds at Mach 1.3 before needing to enter the three-minute cool-down period. Defense News rightly notes how difficult these requirements would be for a pilot to monitor given that they are not simply linear time restrictions. It seems almost impossible that an aviator would be able to keep track of the total seconds of high-speed flight throughout the course of a mission to know if they need to drop speed for three minutes. Needless to say, the requirement to stop short could come at an inopportune time and might easily get ignored during an intense combat situation. But without adhering to these guidelines, there is a danger that areas of the jet's low observable coating would peel off and structural damage would be inflicted to portions of the rear stabilizer. This area also houses key antennas embedded in beneath the F-35's skin. So, we are talking about the possibility of low-observable (stealth) degradation, damage to key components of the jet's sensor system that would keep it from performing key missions, straight up structural damage, and in some circumstances, all three.

USN A pair of US Navy F-35Cs.