After completing at the beginning of 2024 the modernization to Block 70 of 139 aircraft, the Taiwan Air Force continues to advance in strengthening the combat capabilities of its F-16 fighters. The most recent milestone was the confirmation that Lockheed Martin will equip the Fighting Falcons with new Legion-ES infrared search and track (IRST) systems —also referred to as IRST21— through a contract valued at US$ 328.5 million and encompassed within the United States Foreign Military Sales (FMS) Program.
Following the developments of the Taiwan Air Force and focusing attention on its significant fleet of F-16 fighters, the institution has been working on and promoting two programs in parallel. The first, whose completion was announced in February 2024, consisted of the modernization of its F-16A/Bs to Block 70. Although the “Peace Phoenix Rising” program included the upgrade of 144 aircraft, in an operation valued at US$ 4.5 billion, the final number was 139 units due to accidents and operational aircraft losses.
The second program, which has been reporting sustained delays and which still, despite the official presentation of the first aircraft, does not record deliveries, is the provision of 66 new F-16 Block 70 fighters manufactured by Lockheed Martin at its Greenville plant. The latest reports issued by Taiwanese Air Force commanders indicated that the U.S. company is advancing in its efforts to complete during 2026 the delivery of the first Viper combat aircraft.
Returning to what was reported on February 2, Lockheed Martin announced the award of the production contract to equip Taiwanese F-16 fighters with new Legion-ES infrared search and track (IRST) systems. This operation has as its background the authorization issued by the State Department in 2023, through which the possible sale of an undetermined number of systems for a value of US$ 500 million had been approved, therefore it is presumable that the government of Taiwan opted for a smaller number of units.
Regarding the system, the company presents it as “…a passive long-range detection system. IRST21 uses infrared search and track technology to detect and track airborne threats with weapon-quality accuracy, increasing pilot reaction time and enhancing survivability.”
Adding, with regard to its compatible platforms —among which manned and unmanned aircraft are listed— that its compact design “…allows IRST21 to be integrated in various ways. On the F/A-18E/F, IRST21 is mounted in the forward section of the centerline fuel tank. A pod-mounted sensor system with IRST21 is also being developed that will be able to be carried on a wide range of platforms, including the F-15C and the F-16.”
At the same time, it should be highlighted that the inclusion of this class of systems, present in the most modern fifth-generation fighters, has become, in the face of the proliferation of stealth aircraft, mandatory equipment to increase the situational awareness of the aircraft and its pilot.
In the case of previous-generation aircraft, systems such as the IRST21 allow them to incorporate these capabilities, which are vital for operating in highly contested environments saturated with electromagnetic signals due to the presence of multiple air defense and electronic warfare systems.
In addition to its passive detection capabilities thanks to its long-wave infrared sensor, the system can support the guidance of long-range BVR-type air-to-air missiles.
The aforementioned, and in view of its upcoming provision to the Taiwan Air Force, is not a minor detail in light of the threats it would have to face in a potential conflict against China, where it is known that the People’s Liberation Army, through its Navy and Air Force, is incorporating an increasing number of fifth-generation stealth aircraft, such as the J-20 and, more recently, the J-35. The latter have a specific carrier-based version to operate from the new aircraft carrier Fujian and its successors currently under construction.
*Translated by Constanza Matteo
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