A squadron of F-35As flying over Hill Air Force Base in Utah. (Photo courtesy of U.S. Air Force)
AURORA, Colo.–While it may take two years to field, a dual-mount bulkhead in the nose of the Lockheed Martin F-35 to accommodate both the AN/APG-81 radar or the twice as powerful AN/APG-85, both by Northrop Grumman, may help in the F-35 program’s move to Block 4, of which the APG-85 is a critical part.
The dual mount is “an opportunity on a number of fronts,” acting Air Force acquisition chief William “Elvis” Bailey said on Wednesday in a brief interview here at the Air & Space Forces Association’s annual warfare symposium. “When we think about modularity, it’s an opportunity to put something in and give yourself decision space. That’s the way I look at that issue. If I can do that [dual-mount bulkhead], then I have a degree of flexibility to go along with that operational impact.”
“The APG-85’s a helluva radar unless you don’t have one,” he said.
Before going forward on such a dual-mount, however, “it has to present itself as a proposition that’s gonna solve [the problem], and, again, we need jets with radars,” Bailey said.
Radar mountings in the F-35’s nose are different for the current APG-81 and the future APG-85 radar–a difference which has helped complicate fielding of the new radar which was to deliver with F-35 Lot 17 but is now to deliver later. The fiscal 2025 Air Force budget request said that full procurement funding would begin in fiscal 2027 with Lot 21 for the first APG-85 to field on an F-35A by January 2029.
According to the service’s fiscal 2026 budget request, two-year advance procurement (AP) funding for the APG-85 “supports suppliers/systems based on lead time associated with the materials: microcircuits, connectors, magnet assembly, transceiver kits, inductor chips, forward housing assembly, signal processors, radiator structures, amplifiers, and chassis assembly.”
The second year of AP funding “completes material buys, manufactures, and delivers the completed radar for lead time integration into the complete air system aircraft,” the request said.
The APG-85 is to deny adversary use of the electromagnetic spectrum and to allow better weapons accuracy and targeting of enemy airborne and surface radars at greater ranges.
Sources have said that all F-35As delivered to fielded units since last summer have been without radars because the APG-85 bulkhead radar mountings are incompatible with the APG-81, but the Air Force has been able to fly the planes, as long as they are accompanied by and data linked to other F-35As with the older APG-81. In a wartime setting, that would mean all four F-35As in a formation–each dozens of miles apart–would fire on targets picked up by the plane with the radar. Yet, that type of operation is problematic, even given the F-35’s sensor fusion, as a one-radar formation could increase the “ghosting” phenomenon in which the aircraft’s displays sometimes show multiple tracks for the same target aircraft, depending on inputs from different sensors on the F-35.
Asked on Wednesday whether F-35As have delivered to the Air Force without radars, Bailey replied, “I’d have to go back and check with those guys” at the F-35 Joint Program Office (JPO). Bailey said that Marine Lt. Gen. Gregory Masiello, the F-35 program executive officer (PEO), was at the symposium.
The F-35 JPO, the Air Force, Lockheed Martin, and Northrop Grumman have not commented when asked whether F-35As have delivered without radars. Asked on Wednesday whether recently delivered F-35As have had APG-85 mountings that prevented the installment of the APG-81, Bailey replied, “I don’t think that’s going to be the case.”
“The APG-81 is different than the APG-85, and therefore delivering the aircraft, as currently configured, with an APG-85 radar versus an APG-81 radar is challenging,” Rep. Rob Wittman (R-Va.), the chairman of the House Armed Services Committee, said this month.
“The bulkhead configuration is key because for both of the radars, they are very different,” he said. “Remember, the bulkhead configuration allows the placement of the radar towards the attitude of the array, and the attitude of the array makes all the difference in the world about how the radar operates.”
Wittman has been bird-dogging the F-35 program and the contractor team since the fall of 2024 on delays in the delivery of the APG-85, including what he said have been monthly phone calls since then with Masiello, who became the F-35 PEO in July last year, and his predecessor, Air Force Lt. Gen. Michael Schmidt, now retired, who served as the head of the F-35 JPO between July 2022 and July 2025.
A version of this story originally appeared in affiliate publication Defense Daily.
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