Skip to content Skip to footer

Why the JF-17 Block-III Needs a Dedicated IRST System

With a prototype of the Pakistan Aeronautical Complex (PAC)/Chengdu Aircraft Industry Group (CAIG) JF-17 Block-III flying in December 2019, the Pakistan Air Force (PAF) is a step closer to inducting the improved, and much awaited, upgrade of the Thunder multi-role fighter aircraft.

Of the intended subsystem additions, the lack of infrared search and track (IRST) is intriguing. IRST is now becoming a standard capability on so-called “4+” and “4.5” generation fighters, providing those jets with a complementary means of situational awareness (in addition to radar and data-link-based sensor feeds).

This is an important capability as the future of South Asia’s air warfare environment is poised to see heavy use of electronic warfare (EW) and electronic intelligence (ELINT) assets to jam and identify, respectively, radar emissions. Passive sensors, such as IRST, will become a necessity in the future.

However, despite apparent interest in adding IRST to the JF-17, IRST seems to have fallen off from the JF-17 Block-III’s intended feature set. Though the PAF is apparently content with using targeting pods (i.e., ASELPOD) as an infrared sensor, this would not entirely fulfill the role – or benefit – of IRST.

What is Infrared Search and Track (IRST)?

IRST is a sensor that detects and tracks aerial objects using the objects’ infrared signature. IRST systems do not emit any signals of their own, so they are passive. In other words, the aircraft using an IRST system is not vulnerable to exposure as a result of using the IRST.

This is in contrast to using radar which does pose risk of exposure to electronic intelligence (ELINT) and electronic support measures (ESM) suites, such as radar warning receivers (RWR). Of course, to overcome this issue air forces (including the PAF) are adopting active electronically scanned array (AESA) radars with low-probability-of-intercept (LPI) qualities. However, the risk of exposure is still present.

Likewise, because IRST operates outside of the electromagnetic spectrum, it is not vulnerable to electronic warfare (EW) jamming. Thus, if the aircraft is stuck in an EW/ELINT/ESM dense environment with both electronic jamming and exposure, it can rely on IRST as a fallback option to track and target enemy aircraft.

Finally, though IRST relies on infrared signatures, modern IRST systems can track targets at beyond-visual-range (BVR). Likewise, modern IRST systems can also differentiate specific aircraft within formations, so they are not crude by any measure (while still retaining the benefits of being passive sensors). In effect, a fighter with IRST can track its enemies without (necessarily) being tracked itself (if its radar is inactive).

Today, IRST systems are either integrated directly to the aircraft (as is the case with modern Russian and Western European fighters), or deployed through special mission pods, such as the Legion Pod in the US.

How Would IRST Work in Air Combat?

The best real-world reference point for air combat in South Asia would be Operation Swift Retort, which is the first time both the PAF and Indian Air Force (IAF) set their integrated systems against one another.

In this scenario, the use of stand-off EW/ELINT/ESM is a given, and one should also expect even individual combat aircraft to deploy AESA and EW/ELINT of their own. Thus, electromagnetic jamming and exposure are likely to occur against both sides, which necessitates a less controllable factor: IRST.

In this environment, the PAF would certainly network its JF-17 Block-IIIs to read from the Saab 2000-based Erieye airborne early warning and control (AEW&C) aircraft. The Erieye AEW&C would provide the JF-17s with area-wide situational awareness. In turn, the JF-17s can use IRST to hone-in on objects of interest – and at the same time, keep their radars off, thus avoiding EW jamming.

Of course, data-link exchange may result in exposure in terms of ELINT, so if the JF-17s must sever their connectivity with the AEW&C, they can still use IRST. If those JF-17s acquire a target, they would engage it as they normally would if they had been using radar. So, the JF-17s will fire their air-to-air missiles (AAM) to a relative location (i.e., a specific direction and distance) away from the IRST sensor. Once those AAMs are in close enough proximity, they will activate their terminal radar-guided seekers, and engage.

However, by skipping the radar tracking, it would be very difficult (if not currently impossible) for enemy aircraft to determine if the end-user’s aircraft is targeting them. In other words, the enemy’s RWR might only sound-off when the AAM activates its terminal guidance, at which point, it may be too late.

Interestingly, there may be other ways to gather situational awareness outside of radar. One method may be to equip the JF-17 with an ELINT/ESM pod that ‘listens’ for enemy radar and other emissions. This way, once it confirms the presence of an enemy aircraft, it can then use IRST to scan the area. Likewise (albeit with risk of exposure) one can also pair IRST-equipped JF-17s with dedicated stand-off ELINT/ESM aircraft.

In any case, given the benefits of IRST, the advantages available to the JF-17 are also available to the IAF. In other words, if the PAF does not take IRST seriously, it would be at a severe technical deficit against the IAF. Just as the PAF could employ the above scenario, so can the IAF. However, the difference is that the IAF already has an IRST solution in place, while the PAF has not settled on one.

Informally, a number of PAF personnel and analysts have suggested that the ASELPOD can function in the place of IRST. Though a targeting pod could offer higher fidelity infrared footage of the target at a shorter range, it does not offer the long-range situational awareness of dedicated IRST.[1]

What IRST Options Does the JF-17 Have?

IRST is becoming a necessity more so than a differentiating feature, so it is difficult to conclude that the PAF simply skipped it. Rather, the likelier scenario is that the PAF could not secure an IRST system due to it being too sensitive to export. In other words, it would have to wait for an accessible solution from China.

If this is not the case, then a plausible option would be the Leonardo SkyWard IRST platform. In addition to integrating it to the aircraft directly, one can also deploy the SkyWard through a pod.[2] The total mass of the SkyWard is around 40 kg, but it is air cooled as well. It offers both long-wave infrared (LWIR) for air-to-air and medium-wave infrared (MWIR) for air-to-surface tracking.[3]

The PAF could take a page from the U.S. Air Force (USAF) and U.S Navy (USN) by deploying IRST through a pod. One option is to develop a fixed/non-disposable centerline fuel tank and add IRST to its front tip, just as the USN had done with the Super Hornet.[4] This way, the JF-17 Block-III can use its special mission hardpoint for a dedicated EW/ESM pod or targeting pod (without neglecting extra fuel either). In fact, the PAF could also use this approach to add IRST capability to the JF-17 Block-I and/or Block-II.

The other solution from the USAF and USN is developing an analogous solution to the Legion Pod. Though it is best known for deploying the IRST21, the Legion Pod “can accommodate and operate multiple sensors simultaneously, depending on a customer’s requirements.”[5] In other words, the PAF could look at creating a pod that uses the SkyWard (or another IRST), but pairs it with EW/ELINT/ESM. This way, the PAF could equip the JF-17 with multiple capabilities through one pod, which may be the most optimal solution.

Overall, the JF-17 Block III will be the PAF’s only so-called “4+/4.5” generation fighter in its 2020 pipeline, so it should aim to equip the fighter as its qualitative driver. In other words, there should not be any gaps in features or technology capabilities. If such gaps exist, then it would mean the PAF is settling with major deficiencies at a structural level. It would be akin to relying on within-visual-range (WVR) while the other side expands its BVR (which was a structural deficiency through the late 1990s and early 2000s).

[1] Joseph Trvithick and Tyler Rogoway. “F-15C Eagle’s New Infrared Search And Track Pod Spotted At Huge Exercise In Alaska.” The Warzone by The Drive. 18 May 2019. URL: https://www.thedrive.com/the-war-zone/28085/f-15c-eagles-new-infrared-search-and-track-pod-spotted-at-huge-exercise-in-alaska

[2] Product Information. SkyWard. Leonardo. URL: https://www.leonardocompany.com/en/products/skyward-1

[3] Ibid.

[4] Tyler Rogoway. “Infrared Search And Track Systems And The Future Of The US Fighter Force.” Foxtrot Alpha by Jalopnik.com. 26 March 2015. URL: https://foxtrotalpha.jalopnik.com/infrared-search-and-track-systems-and-the-future-of-the-1691441747

[5] Product Information. Legion Pod. Lockheed Martin. URL: https://www.lockheedmartin.com/en-us/products/legion-pod.html

Show CommentsClose Comments

Leave a comment

0.0/5