U.S. Air Force Maj. Kristin “BEO” Wolfe, F-35A Lightning II Demonstration Team pilot and commander, flies over the Toronto waterfront during the 2021 Canadian International Air Show, Sept. 5, 2021. (U.S. Air Force photo by Capt. Kip Sumner)

WASHINGTON — The ongoing delivery pause for upgraded F-35 Joint Strike Fighters has created a backlog that will take about a year for officials to clear out, according to a new watchdog report published today [PDF].

Program officials interviewed by the Government Accountability Office said that the Defense Contract Management Agency and F-35 prime contractor Lockheed Martin work together to accept roughly 13 new F-35 stealth fighters a month. Due to the delivery pause stemming from delays with the Technology Refresh 3 (TR-3) upgrade, officials plan to ramp that up to a monthly average of 20 jets, including aircraft fresh off the line and jets sitting parked at Lockheed’s facilities.

“Even at this faster rate, delivering the parked aircraft will take about a year once TR-3 software has been completed and certified,” GAO found. Presumably, more TR-3 delays — ones that would force the program to miss a goal of restarting deliveries in July under an early acceptance plan that would limit new jets to training for at least a year — could increase the backlog, and time needed to clear it. 

Additionally, GAO found Lockheed is running short on parking space for parked planes, and will need to craft a new plan to find more space if TR-3 delays stretch on. As many as 100 to 120 jets could be “undelivered” by the end of this year as a result of TR-3 issues, Lockheed executives have previously said. Lockheed said today the company has “the necessary secure infrastructure and capacity to park all aircraft until they are ready for delivery” but declined to elaborate due to “security considerations.” 

The $1.8 billion TR-3 effort essentially provides more computing power and memory to support a suite of planned upgrades known as Block 4. Delays in validating TR-3’s software have halted deliveries of many new jets since July 2023, with production also being hampered by hardware challenges. Specifically, GAO found delays with TR-3’s integrated core processor made by L3Harris, whose production is expected to recover by December 2024. TR-3 component delays have impacted both new production and retrofit plans, Breaking Defense previously reported.

“We continue to partner with the Joint Program Office (JPO) and our F-35 industry partners to address GAO recommendations as appropriate. TR-3 is a top priority for Lockheed Martin, and we remain focused on the implementation of the capabilities while also maintaining our full-rate production line to meet continued global demand,” Lockheed said in a statement. L3Harris did not immediately respond to a request for comment. 

Broader production woes have also hindered both engine and aircraft deliveries, GAO found. Though engine manufacturer Pratt & Whitney delivered 100 percent of engines late in 2023, a buffer pool of powerplants established by the program prevented the issue from impacting production. Lockheed delivered 91 percent of aircraft late in 2023 — a number influenced by temporarily halted engine deliveries, TR-3 difficulties, supply chain problems and manufacturing issues — which is the highest in the past six years, according to GAO.

“The majority of F135 delivery delays are driven by industry-wide labor challenges and raw material constraints, in addition to manufacturing challenges on a limited number of specific parts,” a Pratt spokesperson said in a statement. “Despite these challenges, F135 engine production and deliveries did not impact aircraft deliveries in 2023, nor were readiness levels negatively impacted. In fact, F135 deliveries are poised to outpace aircraft deliveries again in 2024, while the F135 program maintains a better than enterprise-wide target of 94 percent Fully Mission Capable rate.”

In a statement, JPO spokesman Russ Goemaere pointed to progress made by the F-35 program highlighted by the report, such as the jet’s long-delayed approval in March for full-rate production. “Our top developmental priority is delivering a safe, stable, capable, and maintainable TR-3 product. The next iteration of TR-3 software is planned for release to flight test later this month,” Goemaere said. “Our team remains focused on incorporating fixes that put us in a position to deliver TR-3 configured aircraft acceptable for combat training. The first opportunity to potentially start accepting aircraft remains late July.

“The JPO remains committed to working with our industry partners to deliver the F-35 to our warfighters to ensure they can fight and win when called to do so,” he added.

Other elements of the sprawling F-35 enterprise continue to vex officials, most notably a dual upgrade for the jet’s engine and separate cooling apparatus known as the Power and Thermal Management System (PTMS). The Pentagon has picked Pratt to upgrade the company’s incumbent F135 engine, though military officials haven’t decided on a cooling system approach.

RELATED: Honeywell unveils new F-35 thermal management fix as Pentagon hunts for better cooling

A PTMS upgrade is particularly needed to support future combat capabilities that could arrive as early as 2029, but officials told GAO 2032 is a more “realistic” date for a new PTMS solution — potentially risking delays for those future capabilities. Deliveries of aircraft with the upgraded engine are not expected until 2032, according to GAO, approximately three years later than a 2029 target date previously shared by Pratt officials. (The JPO additionally told Breaking Defense last year that the dual engine and cooling system upgrades would arrive by 2030, but did not immediately respond today when asked to comment on the timeline discrepancies.)

Other problems like limited testing infrastructure continue to hamstring the F-35 program, prompting lawmakers to take action. The House Armed Services Committee on Monday revealed that House authorizers would move to trim 10 F-35s from the Pentagon’s fiscal 2025 budget request and fence off funding for another 10 jets, steps that committee staff told reporters are aimed at stabilizing the long-troubled program.

Speaking to reporters on Capitol Hill on Wednesday, House Armed Services tactical air and land forces subcommittee Chairman Rep. Rob Wittman, R-Va., told reporters that lawmakers’ patience is wearing thin, noting that he and other legislators have “expressed our sense of urgency” to the Pentagon and industry. 

“I’m not looking in any way, shape, or form to re-litigate how we got here, where to place blame. I don’t care. At this point, I don’t care,” an exasperated Wittman said. “The question is what’s the solution going forward, and we are all in to make this happen.”