Six new F-35Bs entered service carrying ballast inside their noses instead of radarThe APG-85 delay created stealth fighters without their primary sensorLot 17 redesign decisions eliminated compatibility with older radar hardwareThe United States Marine Corps has accepted delivery of six newly built F-35B stealth fighters carrying ballast weights where a radar should be installed.The aircraft left production lines without the AN/APG-85 radar that future F-35 variants are expected to rely upon for combat operations.Instead of delaying delivery, officials accepted aircraft configured with dead weight occupying the nose section reserved for the missing equipment.A new radar arrives before the aircraft can actually use itThe unusual situation emerged because Lot 17 aircraft were redesigned around the forthcoming AN/APG-85 radar architecture and mounting structure.Those modifications prevent installation of the older AN/APG-81 radar, leaving no interim option while the replacement remains unavailable.The radar is to be supplied by Northrop Grumman rather than prime contractor Lockheed Martin, further complicating delivery schedules.Marine Corps Lieutenant General Gregory Masiello informed lawmakers on June 23 2026 that only six Marine aircraft currently lack installed radars.Acceptance testing for those aircraft began in February 2026 after successfully completing production earlier in the year.Although the Air Force and Navy have not yet received comparable aircraft, similar deliveries are reportedly expected later this year.Without radars, the aircraft can support basic flight familiarisation and pilot instruction activities while remaining unsuitable for combat operations.The Joint Program Office defended the decision, stating the Pentagon "deliberately undertook a highly concurrent development and production program for advanced capabilities.""This decision was made with full understanding of the risk of having production aircraft ready ahead of the capabilities."Delay exposes larger questions around F-35 readinessThe missing radar arrives amid wider concerns surrounding operational readiness across the broader F-35 fleet during fiscal year 2025.According to a recent US Government Accountability Office assessment, only about 25% of the F-35 aircraft achieved fully mission-capable status in 2025.Aircraft capable of performing at least one assigned mission reached 44.1%, although this remained considerably below historical expectations.Masiello said he would not "dispute their numbers or how they do it" during congressional testimony discussing the findings.Using Joint Program Office calculations, he argued the mission capable figure stood closer to 56% across operational fleets instead.The delayed APG-85 radar forms part of the wider Block 4 modernization package that continues encountering schedule and integration challenges.Future F-35 models will require more cooling capacity, as new systems will draw between 62 and 80 kilowatts, more than double the 32 kilowatts current hardware consumes.A next-generation engine that could have addressed this cooling gap was developed but ultimately defunded after proving too costly.Current plans indicate that the APG-85 will enter service around 2028 but meaningful cooling will not arrive until after 2031.The sight of stealth fighters carrying lead ballast instead of radars may therefore become an enduring symbol of contemporary defence procurement realities.Via Defence Industry