Northrop Grumman is eying the market to upgrade older Boeing F-15s and F-18s with active electronically scanned arrays (AESA) after flight testing a combination of the active-array radars it has developed for Lockheed Martin’s F-16 and F-35 fighters.

The May flight test in a BAC One-Eleven radar testbed owned by Northrop showed that the high-performance front-end array from the F-35’s APG-81 radar could be combined with the affordable back-end receiver/exciter/processor from the Scalable Agile Beam Radar (SABR) under development for retrofit into the F-16.

Intended as a drop-in replacement for Northrop’s APG-66 and -68 mechanically scanned radars in the F-16, the SABR is sized to fit in the fighter’s nose without modification and operate within the available air-cooling capacity, and priced for the retrofit market.

The F-15 and F/A-18 can accommodate larger, more-powerful radars, like the liquid-cooled APG-81 AESA. But Northrop would have to oust incumbent Raytheon, which is already supplying AESAs for both aircraft.

The May flight test showed the performance on the APG-81 can be combined with the affordability of the SABR, says Pat Antkowiak, vice president and general manager of Northrop Grumman Electronic Systems’ advanced concepts and technology division.

The APG-81 transmit/receive array and SABR single-box receiver / exciter / processor (REP) were integrated and flown in the One-Eleven “in weeks,” he says.

The SABR REP has a more open architecture than the APG-81, which uses proprietary hardware and software. “This unlocks the insertion of new technology and opens the market for legacy platforms,” Antkowiak says.

“If we take the APG-81 technology and combine it with the affordability of the REP we have a value proposition, both domestically and internationally,” he says.

The U.S. Air Force plans to put some 300 Block 40/42 and 50/52 F-16C/Ds through a service life extension and combat avionics upgrade, including a new AESA radar, because of delays in development and fielding of the F-35A.

Lockheed will be prime integrator for the upgrade, but the USAF will conduct a separate competition for the AESA, says Joe Ensor, vice president and general manager of Northrop’s intelligence, surveillance, reconnaissance and targeting systems division.

Although the incumbent radar supplier on the F-16 , Northrop and its SABR will face competition from the Raytheon Advanced Capability Radar (RACR). “It will be a government source selection. We are awaiting a draft request for proposals,” says Ensor.

Beyond the F-16 market , the U.S. Navy has around 100 Block I F/A-18E/F Super Hornets that are candidates for a radar upgrade . Earlier F/A-18s operated domestically and internationally are also possibilities for AESA retrofits.

The Air Force is upgrading its F-15Es and some F-15Cs with Raytheon AESAs, but some older aircraft and F-15s operated by international customers remain candidates for radar retrofits.