F-35B could hit service life limit by 2026

The F-35A aircraft seems unaffected but another bad surprise to the F-35 program has been discovered, hopefully without impact on the Belgian fleet. Oldest F-35B could hit service life limit in 2026.

Five F-35Bs shown here on deck and taking off from the USS America during F-35B Development Test III (DT-III) (Picture source : Lockheed Martin)

According to the US Pentagon, some structural defects have been discovered on the F-35B, meaning the earliest F-35Bs delivered by Lockheed Martin could reach a service life limit by 2026, after only but 2,100 flight hours. Initially, the design specification of the F-35B was scheduled to allow the aircraft reaching 8,000 flight hours. Though, early production models fall "well under" the durability requirement, according to Robert Behler, director of operational test and evaluation (DOT&E).

The new DOT&E assessment comes after several years of durability testing that exposed multiple structural issues. Lockheed Martin completed 2 service lifetime cycles of durability testing on a static F-35B airframe called BH-1, but canceled a plan in February 2017 to perform a 3rd series. “Items identified in the Annual DOT&E report are well understood and have been resolved in partnership with the F-35 Joint Program Office or have an agreed path forward to resolution,” Lockheed said in a statement to Aerospace DAILY. Moreover, planned design changes should allow the early F-35Bs to meet the service life requirement of 8,000 flight hours, a program source says.

In addition to that, Behler also remains skeptical about the F-35 program’s decision to reorganize parts of the Block 4 modernization plan. Instead of rolling out large increments every two years, the Continuous Capability Development and Delivery plan adopted a year ago calls for releasing smaller software updates adding new features every six months.

The DOT&E is also critical about the readiness of the F-35’s Block 3F software a month after the program entered a critical testing phase. Software updates and fixes rolled out by Lockheed reduced the number of Category 1 deficiencies to 13 in December from more than 100 last May. The program later added two more Category 1 deficiencies to the list after the F-35 entered the initial operational test and evaluation phase on Dec. 5, the report states.