A US Air Force (USAF) F-15C Eagle for the first time downed a QF-16 target drone using an AIM-120 Advanced Medium-Range Air-to-Air Missile (AMRAAM) guided by an infrared search-and-track (IRST) system.

The Boeing F-15C used Lockheed Martin’s Legion Pod IRST block 1.5 system for the AMRAAM test, which happened on 5 August, says the service on 10 August.

The USAF wants to give the F-15C the ability to counter stealth aircraft

IRST systems are being evaluated as a means to guide air-to-air missiles to stealth aircraft, which are designed to be difficult to target using radar alone. IRST systems use passive sensors, meaning the equipment does not broadcast signals that can reveal an aircraft’s location.

As part of the recent test, which took place at Eglin AFB in Florida, the Legion Pod IRST system worked in coordination with Raytheon’s APG-63v3 electronically scanned array radar to transmit the QF-16 drone’s location to the Raytheon AIM-120 missile, says the USAF. Boeing sells QF-16s, which are Lockheed Martin F-16s modified to be autonomous.

“This successful live missile test is significant because an F-15 equipped with an IRST-cued AIM-120 allows us to achieve detection, tracking, targeting, weapons employment and verification of an intercept without being dependent upon radar energy,” says Major Brian Davis, 85th Test and Evaluation Squadron chief of air-to-air weapons and tactics. “It’s also not susceptible to radio frequency jamming or a target’s low-observable design.”

In July 2020, the USAF demonstrated an IRST Legion Pod guiding the short-range AIM-9X Sidewinder missile, also fired from an F-15C, to a target drone.

The USAF wants IRST sensors across its combat fleet to counter the emergence of stealth aircraft within the air forces of China and Russia. As part of that effort, the service’s F-16s are also to be equipped with Legion Pods. Lockheed Martin F-35As come equipped with IRST sensors.

China’s Chengdu J-20 stealth fighter entered service in 2017 and Russia’s Sukhoi Su-57 entered service in December.