The latest generation of F-35 fighter jets that the United States plans to begin delivering this fall will enter service without onboard radar systems, according to reporting by Breaking Defense citing informed sources. The issue stems from delays in the development of an upgraded radar, leaving the aircraft temporarily unfit for full combat operations.

At the center of the problem is the new APG-85 radar, intended to replace the current APG-81. The updated system differs in size, and aircraft designed to accommodate it are already being built with a modified nose section and internal structure. The Pentagon had aimed to align the rollout of the new radar with production of the Lot 17 batch of F-35s. However, development setbacks have pushed the radar’s readiness behind schedule, meaning the jets themselves will be completed first.

Retrofitting the older APG-81 radar into the redesigned airframe is not an option due to these structural changes, the report notes.

Sources indicate that, at best, a finalized version of the APG-85 could be ready next year. If the delay remains short-lived, only a limited number of aircraft will be affected. But if timelines continue to slip, more than 100 fighters could be delivered without operational radar systems, effectively carrying placeholder equipment instead.

Even in this configuration, the aircraft will still be capable of flying and can be used for training. However, their deployment in combat roles will not be possible.

According to Breaking Defense, the Pentagon’s Lot 17 contract covers 126 aircraft. Two subsequent production batches-Lot 18 and Lot 19-are expected to include 148 jets each.