Image Courtesy: AirPower on X
The U.S. Marine Corps has accepted delivery of six newly built F-35B stealth fighters without their primary radar systems, instead flying with lead ballast installed in the nose to replace the missing equipment. The aircraft can be used for pilot training and familiarization flights but are not ready for combat missions.
The unusual configuration stems from delays to the new Northrop Grumman AN/APG-85 radar, which is intended for future F-35 variants. The latest Lot 17 aircraft were redesigned specifically for the new radar, making them incompatible with the older AN/APG-81 system and leaving no temporary replacement available. Defense officials have acknowledged the issue while opting to accept the aircraft rather than postpone deliveries.
Marine Corps Lieutenant General Gregory Masiello told lawmakers on June 23 that only six Marine Corps aircraft currently lack installed radars. Similar deliveries are expected to affect the U.S. Air Force and Navy later this year as production continues ahead of radar availability.
The Pentagon defended the decision, saying it deliberately accepted the risks of producing aircraft before some advanced capabilities were ready. Officials said the aircraft can still support non-combat activities while awaiting installation of the new radar.
The delay is part of the broader Block 4 modernization effort, which has faced repeated scheduling and integration challenges. The APG-85 radar is expected to enter service around 2028, but its full performance will depend on upgraded cooling systems that are not expected until after 2031. Future F-35 systems are projected to require between 62 and 80 kilowatts of cooling capacity, more than double what the current aircraft can provide.
The radar delays come as the F-35 program continues to face readiness concerns. A recent U.S. Government Accountability Office report found that only about 25% of F-35s were fully mission capable during fiscal year 2025, while 44.1% could perform at least one assigned mission. Program officials have argued the actual mission-capable rate is closer to 56% using different calculations.
