Undelivered Lightning IIs Relegated to Storage

The U.S. military, Lockheed-Martin, and Pratt & Whitney have reportedly identified a potential solution to the engine troubles by which deliveries of the costly and controversial Joint Strike Fighter have been halted for nearly two months.

U.S. Congressman Rob Wittman (Republican, Virginia), who chairs the House Armed Services Committee’s tactical air and land forces panel, set forth that engineers have attributed the F-35’s woes to anomalous vibrations detected within the Pratt & Whitney F135 engines by which the fifth-generation fighters are powered. The Congressman intimated a fix for the vibrations could be actualized by late February 2023.

Representative Wittman stated: “The good news is the Air Force and the contractor [Pratt and Whitney] … did their due diligence to discover what the issues were there, and to make sure they gathered the data to make sure they put in place a proper solution.”

Wittman divulged he’d been briefed on 08 February 2023 by F-35 Program Executive Officer Lieutenant General Michael Schmidt.

“I’m very confident that they have properly identified the problem,” Wittman added, “and that their solution set that they’re going to put in place will solve the problem. They’re doing the adequate testing to make sure that their solution does indeed avoid this particular situation in the future.”

Wittman further stated the as-of-yet undisclosed solution “should be in hand any day now.” Asked if his estimate implied February, the Congressman asserted: “That’s my understanding.”

Pratt & Whitney confirmed the development of a near-term solution to the F-35’s powerplant ailments would allow the storied engine manufacturer to resume deliveries of F135 engines to F-35 designer and principal manufacturer Lockheed Martin by the end of February 2023.

Pratt & Whitney F135 program manager Jen Latka remarked: “After thorough review, we can confidently say there were no quality issues with the [engine] fuel tube that fractured. We are dealing with a rare systems phenomenon involving harmonic resonance.

“We have developed a near-term remedy that allows the fleet to fly safely, and we expect that F135 engine deliveries could resume before the end of the month.”

Pratt & Whitney, consistent with the high degree of secrecy in which the F-35 program is veiled, provided no details of the ostensible fix. Ergo, it remains unclear when, precisely, Lightning II acceptance flights and deliveries will resume.

Lockheed halted F-35 acceptance flights following a 15 December 2022 incident in which an F-35B pending delivery to the U.S. Marine Corps was damaged in a vertical landing mishap at Naval Air Station Joint Reserve Base (NAS JRB) Fort Worth—a U.S. Navy installation approximately five-nautical-miles west of Fort Worth, Texas.

After appearing to touch down normally from a low-altitude hover, the Short Takeoff Vertical Landing (STOVL) fighter lurched forward in a nose-low attitude, collapsing its nose landing-gear and coming abruptly to rest on its snout. The aircraft then entered a series of partial ground-loops, pivoting—more or less—about its radome and grounded starboard wing until the lone pilot ejected, coming safely to ground beneath a fully deployed parachute canopy.

A source familiar with the F-35 program revealed in December 2022 that initial assessments of the downed F-35B had indicated the failure of a high-pressure fuel tube within the aircraft’s F135 engine. The incident compelled the F-35 Joint Program Office (JPO) to update its safety risk assessment protocols.

On 27 December, following what the JPO called a “mutual agreement” between itself, the Defense Contract Management Agency (DCMA), and Pratt & Whitney, deliveries of new F135 engines were suspended pending further investigation of the 15 December, Fort Worth incident.

Congressman Wittman, too, confirmed: “there was a problem with the high-pressure fuel-delivery system.”

Wittman stated the solution by dint of which F-35 acceptance flights and deliveries will presumably resume involves a “combination of things” to dampen engine vibrations. The Republican representative pointed out, however, that the manufacturing processes upon which the unspecified fix are predicated have yet to be developed by the germane contractors. What’s more, the re-engineered components, once extant, must be retrofitted into the 17 F-35s Lockheed-Martin has built since December 2022.

“I believe that the Air Force and Lockheed have the solution set in hand, which is the key,” Wittman posited. “Then … how do they incorporate that into existing aircraft and aircraft that are on the assembly line now?”

FMI: www.lockheedmartin.com