The F-35 Joint Program Office (JPO) has declined to confirm or deny reports that the U.S. military is taking delivery of F-35 Joint Strike Fighters without installed radars, even as a growing body of publicly available information strongly suggests that such deliveries are underway. At the center of the controversy is the next-generation AN/APG-85 radar, a cornerstone of the long-delayed and increasingly expensive Block 4 modernization package.
Defense Daily first reported last week that radar-less F-35s began arriving in June 2025, citing an unnamed source. According to the report, all F-35A variants delivered to the U.S. Air Force since that time have lacked installed radars. The article did not explain how or why the Pentagon opted to accept aircraft in that configuration. Notably, foreign customers — who continue to receive jets equipped with the older AN/APG-81 radar — are reportedly unaffected.
In response to inquiries, a spokesperson for the F-35 JPO told: “F-35 Lightning II aircraft are being built to accommodate the F-35 advanced radar (APG-85) for the U.S. Air Force, Navy, and Marine Corps. Initial fielding for some F-35 aircraft is planned for Lot 17, which began delivery in 2025 and continues through September 2026.”
The spokesperson added that, “Due to program security reasons, we are protecting any additional information with enhanced security measures.”
Lockheed Martin, the prime contractor for the F-35 program, referred questions back to the JPO. Northrop Grumman, which is developing the APG-85 radar, declined to comment.
The AN/APG-85 represents a major technological evolution over the AN/APG-81 radar currently fielded on operational F-35s. Both are active electronically scanned array (AESA) radars capable of air-to-air and air-to-ground operations. The new radar is also expected to include synthetic aperture radar (SAR) mapping capability, enabling the production of high-resolution ground imagery for target identification and reconnaissance.
While many technical details remain classified, the APG-85 is widely believed to incorporate modern gallium nitride (GaN) technology. GaN-based transmit/receive modules offer substantial improvements in power efficiency, heat tolerance, and output compared to earlier gallium arsenide designs. These enhancements can translate into longer detection ranges, improved electronic attack capabilities, and more resilient performance against jamming.
Low probability of intercept and low probability of detection (LPI/LPD) features are also expected to be central to the APG-85’s design. Such capabilities are particularly important for stealth aircraft like the F-35, whose survivability depends not only on shaping and radar-absorbent materials but also on minimizing electromagnetic emissions that could betray their presence.
In addition, the radar is deeply integrated with the F-35’s electronic warfare suite and sensor fusion architecture. The aircraft’s combat effectiveness depends on this tight integration, enabling it to combine radar data with inputs from passive sensors, including the Distributed Aperture System (DAS), Electro-Optical Targeting System (EOTS), and offboard data sources.
Although the JPO has not confirmed radar-less deliveries, multiple publicly known facts lend credence to Defense Daily’s reporting.
The JPO has acknowledged that Lot 17 aircraft — deliveries of which began in 2025 — are being built to accommodate the APG-85. However, the radar remains under development and has not yet been declared ready for operational fielding.
Rep. Rob Wittman (R-Va.), Vice Chairman of the House Armed Services Committee and Chairman of its Tactical Air and Land Forces Subcommittee, has confirmed that integrating the APG-85 requires structural modifications to the F-35.
“The bulkhead configuration is key because for both of the radars, they are very different,” Wittman told Defense Daily earlier this month. “The bulkhead configuration allows the placement of the radar toward the attitude of the array, and the attitude of the array makes all the difference in the world about how the radar operates.”
He later added, “I know all about it, but the delivery of the aircraft is classified. I can’t speak to the condition of the aircraft.”
Complicating matters further, Defense Daily reported that a mounting solution capable of accommodating both the APG-81 and APG-85 does not currently exist and would take approximately two years to develop.
A June 2025 report by Breaking Defense supports that timeline. It cited a letter from Lockheed Martin CEO Jim Taiclet to then-Air Force Chief of Staff Gen. David Allvin proposing a redesign of the aircraft’s forward fuselage to accommodate either radar. According to that letter, the redesigned fuselage would likely debut in Lot 20 production, with deliveries beginning around 2027 or 2028.
Until then, it appears that a structural incompatibility may prevent easy installation of the legacy APG-81 into aircraft already configured for the APG-85.
If U.S. forces are indeed receiving F-35s without radars, the operational implications are complex.
According to Defense Daily’s source, radar-less jets have flown with additional nose ballast to maintain proper weight balance. These aircraft reportedly operate alongside F-35s equipped with APG-81 radars, sharing data via the Multifunction Advanced Data Link (MADL).
In such formations, as long as one aircraft has a functioning radar, others can benefit from its sensor data. The F-35’s architecture is designed for cooperative engagement, enabling sensor information to be fused and distributed across the formation.
However, operating without an onboard radar still imposes significant limitations. A radar-less F-35 would lack independent air-to-air detection capability and would be more reliant on passive sensors or offboard data. Tactical flexibility would be reduced, particularly if formations were forced to disperse.
Moreover, the radar is not merely a detection tool; it is integral to the aircraft’s electronic warfare capabilities. AESA radars can generate narrow, high-powered beams for electronic attack, contributing to self-protection and suppression of enemy air defenses. Without the radar, these capabilities would be curtailed.
The F-35 would not be “blind,” given its extensive passive sensor suite and access to Link 16 network data, but its combat effectiveness would be degraded.
The situation recalls earlier phases of the F-35 program, which was characterized by “concurrency” — the simultaneous development and production of aircraft. While intended to accelerate deployment and reduce costs, concurrency resulted in multiple aircraft configurations and extensive retrofits.
The consequences are still being felt. Maintenance complexity and logistical burdens remain elevated due to configuration differences among jets delivered in different production lots.
The Block 4 upgrade effort, along with the related Technology Refresh-3 (TR-3) hardware and software improvements required to support it, has encountered similar turbulence. In September 2025, the Government Accountability Office reported that Block 4 costs had grown by $6 billion and that the effort was at least five years behind schedule.
Block 4 includes not only the APG-85 but also a new electronic warfare suite, upgrades to DAS and EOTS, expanded data-sharing capabilities, enhanced computing power, and improved thermal management systems.
One of the most significant constraints facing the APG-85 integration is electrical power and thermal capacity. The F-35’s Pratt & Whitney F135 engine was originally underspecified for future growth, a shortfall the JPO publicly acknowledged in 2023.
“The arrays on it give it much more power which is why we have to upgrade the engine,” Wittman said. “I think we need about 82 kilowatts of power versus what it’s producing right now.”
An engine upgrade program is underway but remains behind schedule. Without enhanced power generation and cooling, fully exploiting the APG-85’s capabilities may be difficult.
For now, foreign F-35 operators appear insulated from APG-85-related delays, as they continue receiving aircraft equipped with the APG-81. However, long-term uncertainty surrounding Block 4 may influence partner nations’ upgrade decisions.
There have already been reports that some countries are considering deferring or skipping certain Block 4 enhancements. Meanwhile, political friction between Washington and certain allies has introduced additional uncertainty. Canada, for example, is reviewing its F-35 acquisition plans amid trade disputes with the United States, though it continues to fund its order for 88 aircraft.
With 20 nations now operating or procuring the F-35, any significant disruption to the program has global implications.
At present, there is no official confirmation that radar-less F-35s are entering U.S. service. Yet the combination of structural redesign plans, mounting incompatibilities, development delays, and classified delivery details strongly suggests that at least some aircraft may be arriving without installed radars, pending future integration.
Whether this represents a short-term production workaround or a more serious structural challenge remains unclear. What is certain is that the APG-85 is only one component of a broader modernization effort that continues to face technical, financial, and scheduling headwinds.
As the Pentagon pushes forward with Block 4, the question is not merely when the APG-85 will be ready — but whether the F-35 enterprise can reconcile its ambitious upgrade roadmap with the realities of engineering complexity and budgetary constraint.
For the world’s most widely deployed fifth-generation fighter, the stakes could hardly be higher.
