It appears that the USAF is getting very serious about the passive detection threat posed by modern infra-red search and track (IRST) systems, most notably against aircraft optimized for minimal radar observability (see F-22,  B-2, F-35, RQ-170 etc). The sensor shown in the photo above, shot during RED FLAG 13-3 that concluded just days ago, is clearly a chin mounted variant of Lockheed Martin’s very capable and ever evolving AN/AAS-42 IRST which originally was fielded on the F-14D and is now an integral part of the latest F-15 Strike Eagle “Tiger Eyes” targeting and navigation sensor suite.

Such a modular system allows an aircraft carrying it to search, track and target an enemy aircraft passively, allowing for almost zero electromagnetic signature if other measures, aside from just turning off the aircraft’s radar, are taken by the operator to shore up the jet’s electronic emissions. With modern data links, especially in receive only mode, that “passive” IRST equipped aggressor could still maintain a synthetic radar “picture” of the battlespace supplied by external sensors. Such tactics can almost totally eliminate the edge provided by advanced electronic service measure systems found of cutting edge fighter aircraft. These systems are essentially incredibly sensitive electronic “listening” and geo-locating systems that use high-speed computer processing and interferometry to detect and locate enemy electronic emissions.

To over-simplify this, if a fighter pilot turns off their radio/EM transmitting systems, radars, radios, jamming systems etc, than you force the other guy (especially advanced fighter aircraft without an IRST, see F-22) to use their radar to detect you (let’s not get into netcentric battlespace and data links here), and that could give away their location. In other words, instead of shining flashlights (scanning with radars) at one another in a dark room you are looking and waiting for the other guy to turn on his flashlight while you remain cloaked in the darkness. Now, an IRST equipped jet would allow you to bypass even a passive electromagnetic detection (waiting for the other guy to turn on his radar) by having the ability to actively scan for an enemy’s precense without emitting any electromagnet energy. In other words, it is like having a pair of night vision goggles on in that dark room. No need to wait for the other guy to turn on his radar while remaining electromagnetically silent, you can detect, track and engage him by detecting his physical infra-red signiture without giving away your precense or location.

Electromagnetic silence, when paired with other coaltion aircraft using disimillar tactics, such as active radar scanning and jammimg, against a more advanced threat can give the less advanced force a fighting chance at having a number of aircraft “break through” the more advanced enemy’s fighter screen. An IRST equipped fighter force can allow that same less advanced force to work more independently with a greater chance of survivability against a non-IRST equipped advanced threat. Now you install an IRST system in a low observable aircraft that is stuffed with sensors and communications gear tailor made to have a low probability of detection and you have a very stealthy and quiet wildcard. The F-35’s DAS system, which has an embedded IRST capability will, when paired with its stealthy design and cutting edge avionics, should be a serious wildcard in the air to air realm. Alternatively, an F-22 with a similar system would be an even more potent killing machine.

What is not clear is exactly how this program was fielded as the F-15C/D fleet had its IRST delayed/cancelled under the Golden Eagle roadmap, instead SNIPER pods were supposed to be deployed as a stopgap measure. I would guess that the sudden deployment of a podded and proven IRST with the 64th AGRS for what was the largest RED FLAG in years was most likely procured and fielded in a modular format with limited aircraft integration along the same lines as systems procured through the USAF’s “Big Safari” rapid testing and fielding unit. Such a deployment could also provide incredibly relevant data and operational experience for the manufacturer, Lockheed Martin. What is not clear is just how deep this program goes, will an IRST become a staple of the USAF’s aggressor fleet or was this a more limited test? Under the current budgetary realities it is possible that this may have been a contractor funded limited endeavour, although I really hope that this is not the case.

Stay tuned as my full “Red Flag’s Future” feature will be posted soon…

*A huge thanks to to fellow aviation photographer and associate editor of Fencecheck.com Mark Munzel for allowing me to share this awesome shot!

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  1. Ian Hall says:

    You do wonder with all the money that is being spent on the F-35 if someone somewhere is spending a much smaller (but no more valuable) amount of money on detecting the likes of the F-22, F-35 and B-2.

  2. Samy says:

    Such capacity is already fielded on russian and french aircrafts.

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