“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,” said Rep. Rob Wittman, chairman of the House Armed Services Committee’s Tactical Air and Land Forces panel. He said the bulkhead design is critical because “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.”
A dual mounting solution that could accommodate both radars would take about two years to field, according to Wittman. He said aircraft deliveries are classified and added, “I can’t speak to the condition of the aircraft so you’ll have to go to the Air Force, the customer, and ask them about that.”
Wittman said he has pressed both Lockheed Martin and Northrop Grumman to accelerate APG-85 delivery and integration with Technology Refresh-3 and Block 4 upgrades. “They’re doing some things to try and integrate it with Technology Refresh-3 and Block 4,” he said, adding, “I’d like to see them compress it even more. I think they can do that.”
The APG-85 program has faced technical hurdles, including extended testing driven by the demands of a Gallium Nitride-based radar requiring increased cooling and power in the F-35’s nose. Wittman said testing timelines have since been shortened, noting that “they’ve condensed the testing regime” and “have been able to truncate some of those things” to speed delivery.
The new radar is intended to improve electronic warfare, targeting, and weapons accuracy at greater ranges. “It’s an incredibly advanced radar,” Wittman said, adding that its increased power requirements are why the F-35 needs engine upgrades and that “the APG-85 is key to Block 4, and it’s key to TR-3 software upgrade capabilities and integration with the imaging system, the Distributed Aperture System.”
F-35 aircraft delivered to U.S. units since last June have been built with APG-85-compatible mountings, which cannot accept the APG-81, requiring additional nose ballast to maintain balance during flight. Radar-less jets can operate if accompanied by other F-35s equipped with APG-81 radars and connected via data links, while deliveries to foreign partners, including those receiving APG-81-equipped aircraft, have not been affected.
An Air Force spokeswoman said on Feb. 3 that joint development of the APG-85 by the Air Force, Navy, and Marine Corps will help defeat “current and projected adversarial air and surface threats,” adding that “this advanced radar will be compatible with all variants of the F-35 aircraft.” The service said further details are protected for security reasons.
F-35 deliveries resumed in July 2024 after a pause linked to TR-3 software issues needed for Block 4 capabilities. Northrop Grumman disclosed development of the APG-85 in January 2023, but funding levels and contract details for the radar have not been publicly released.
Source: Avionics International.
