Lockheed Martin has further delayed delivery of the first F-35 upgraded with new avionics, to the second quarter of 2024, adding more jets to a backlog of deferred shipments since 2020, the company announced on Sept. 6.

The latest schedule slip means Lockheed now expects to deliver only 97 F-35s this year, a further reduction from an estimate in July of 100-200. 

The company originally planned to deliver 147-153 this year. 

The delays are being caused by scheduling with an ongoing certification process for the software in the Technology Refresh-3 (TR-3) hardware, which includes an L3Harris integrated core processor, an aircraft memory unit and an RTX electro-optical distributed aperture system, Lockheed says in a new regulatory filing. 

L3Harris and RTX have also fallen behind on deliveries of TR-3 hardware. 

The delay adds to growing pressure on Lockheed’s annual delivery rates. The COVID-19 pandemic caused the company to fall behind by 21 aircraft deliveries in 2020, but the assembly line bounced back the next year and beat a 133-139 jet delivery target with 142 aircraft. But a late-December F-35 crash during a flight test in 2022 revealed a new engine design flaw, again causing a missed delivery target for 2022 with only 141 aircraft. 

Lockheed has delivered 403 F-35s over the past three years, but had planned to deliver a maximum of 433. 

Including the current estimate that calls for delivering 97 F-35s in 2023—or up to 56 fewer than originally planned at the beginning of the year—Lockheed’s backlogged shipments since 2020 now total up to 86 jets. 

To catch up on deferred shipments as well as handing over a planned total of 156 in 2024, Lockheed will need to deliver as many as 242 F-35s next year, or 100 more than achieved in 12 months so far. 

The delays have already forced some customers to revise schedules. The Belgian Air Force has already acknowledged its first F-35A delivery has been delayed to 2024. The U.S. Air Force, which is Lockheed’s largest F-35 customer, is continuing to stand up new squadrons, but it will take longer for all the aircraft to arrive at each new unit, says Gen. Mark Kelly, the head of Air Combat Command. 

“When a unit converts to a new airplane, usually by the time they get their last airplane, the clock starts and they’re going to be ready to go a year or so later. Well, that will delay and impact ... global force management,” Kelly said at a Defense News conference on Sept. 6. 

Despite the problems caused by the delays, Kelly emphasizes the inherent schedule risks involved in integrating advanced technology on the F-35. 

“The high-end software and high-end hardware, high-end [electronic warfare] is hard business,” Kelly says. “There are more nations around the planet that can build a nuclear weapon than can develop an integrated core processor and mate it with that hardware.”

So far, the delays do not appear to have caused damage for the only stealth fighter now in production for the international market. 

On Dec. 3, Israel’s Ministry of Defense announced it had started to acquire a third batch of F-35Is, which would raise its overall fleet to 75 jets. 

“The procurement delegation of the Ministry of Defense in the USA submitted a request for procurement with the aim of completing the transaction in the coming months,” the ministry said.