F/A-18’s Infrared Search And Track System Has “Significant Reliability Problems”

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The U.S. Navy’s podded Infrared Search And Track System, or IRST, planned for its F/A-18E/F Super Hornet fighters, has “demonstrated significant reliability problems during operational testing,” according to the Pentagon. The ASG-34A(V)1 IRST Block II, seen as a key part of the Navy’s ability to retain its air-to-air advantage over potential adversaries, was first flown on a Super Hornet in late 2019 and TWZ had previously reported on delays caused by production quality issues with the system.

The Office of the Director, Operational Test & Evaluation, in its latest Annual Report, provides an update on the status of the IRST Block II pod, which completed operational testing in the fourth quarter of FY24. These tests involved Infrared Optimized Configuration (IROC) pods, described as “operationally equivalent” but designated for flight test.

A Lockheed Martin infographic showing different applications for its IRST2 1 sensor, including the podded version for the Navy F/A-18E/F Super Hornet. Lockheed Martin

While finishing operational testing is a significant milestone, it’s tempered by the fact that, according to the report, “operational test events were adversely affected by IRST Block II system reliability failures.” Data analysis is ongoing.

As we have discussed before, including with the Super Hornet program manager, the centerline-mounted F/A-18E/F IRST pod provides the aircraft with a long-wave infrared sensor — the Lockheed Martin-developed IRST21 — that can search, detect, and track airborne targets. Very importantly, it is an ideal tool for detecting stealthy targets, which are proliferating. The IRST sensor assembly is installed in the front portion of a redesigned FPU-13/A centerline fuel tank.

A conceptual diagram of how the IRST sensor is mounted in the fuel tank for the Super Hornet. Lockheed Martin

Very importantly, the IRST pod provides an entirely passive capability, relying exclusively on the infrared spectrum to detect and track airborne targets, including those at far beyond visual range. With no radio-frequency emissions, the target won’t be alerted to the fact that they’ve been detected and are being tracked. At the same time, the IRST does not give away the location and presence of the host platform. This kind of sensor also provides a vital companion to the Super Hornet’s AN/APG-79 radar, functions of which may well be compromised in a heavy electronic attack or radar-denied environment.

At the same time, the IRST Block II pod still contains fuel to extend the Super Hornet’s range, although this is trimmed from 480 gallons to 340 gallons once the sensor is fitted.

In terms of the timeline for the system, developmental testing was conducted during FY23 and FY24, followed by initial operational test and evaluation (IOT&E) between April and September 2024, with the IROC pods, in support of full-rate production.

In the meantime, however, earlier iterations of the pod had already been deployed on operations, carried by Super Hornets in the Middle East, with photos emerging of this in late 2020.

A U.S. Navy F/A-18F Super Hornet, from the "Mighty Shrikes" of Strike Fighter Squadron (VFA) 94, flies over the U.S. Central Command area of responsibility during a mission in support of Operation Inherent Resolve, Sept. 30, 2020. VFA-94 is assigned to Carrier Air Wing 17, deployed aboard the aircraft carrier USS Nimitz (CVN 68), flagship of Nimitz Carrier Strike Group. The F/A-18F is designed to perform fighter escort, fleet air defense, suppression of enemy air defenses, air interdiction, close air support, and aerial reconnaissance. (U.S. Air Force photo by Staff Sgt. James Merriman)
A U.S. Navy F/A-18F, with an IRST pod on the centerline, flies over the U.S. Central Command area of responsibility during a mission in support of Operation Inherent Resolve, Sept. 30, 2020. U.S. Air Force photo by Staff Sgt. James Merriman Staff Sgt. James Merriman

When it comes to the suitability of the pod for full operational fielding, the report provides the following comments:

In an operational context, the report notes that the IRST pod is seen as a complementary sensor to the AN/APG-79 “to support the guidance of beyond-visual-range air-to-air missiles,” either operating autonomously or in combination with other sensors. The missiles mentioned are the AIM-120 Advanced Medium-Range Air-to-Air Missile (AMRAAM) and the AIM-9X Sidewinder Block II.

“IRST Block II demonstrated significant reliability problems during operational testing. Throughout the test period, IRST Block II suffered from hardware and software deficiencies, which required the aircrew to restart the pod multiple times. Troubleshooting and repair often exceeded the abilities of Navy maintenance crews and required assistance from Lockheed Martin. Many of these problems were discovered during integrated and operational test after the Navy completed a minimal developmental test program with the representative hardware. Additional details will be provided in DOT&E’s classified IOT&E report.”

Despite these problems, the report notes that the test events were “adequate to provide an assessment of the long-range detection and tracking capability, suitability, and cyber survivability” of the pod.

Specifically, test events saw the pod being used against “operationally relevant targets” at “tactically relevant detection ranges.” Here, the pod demonstrated that it could translate long-range target detections into stable system tracks that would be suitable for weapons employment.

The Lockheed Martin IRST21 sensor, as used in the Navy Super Hornet IRST pod. Lockheed Martin

However, there is clearly still work to be done, with the report adding that the Navy “must continue to improve the F/A-18 E/F Super Hornet’s operating software and address existing deficiencies to effectively integrate IRST into aircraft fire control solutions.”

The Pentagon hopes that the Low-Rate Initial Production (LRIP) pods, which were planned to be delivered starting in September 2024 “may have increased reliability” and will “improve lethality and survivability in air superiority missions against advanced threats.”

As well as the reliability deficiencies outlined in this latest report, the Pentagon also notes that more work needs to be done to address IRST Block II and Super Hornet operating software deficiencies that had been recommended in the last such document, in FY23.

Previous issues with the pod were also highlighted by the U.S. Government Accountability Office (GAO), in its 2023 Report to Congressional Committees.

This earlier report noted that “between 20 and 30 percent of the manufactured components [in the IRST pod] failed to meet performance specifications due to microelectronics issues.” These problems persisted more than four years after limited manufacturing had begun and served to delay the launch of developmental and operational testing.

The 2023 report also highlighted the fact that “staffing challenges” at a critical software development contractor were also leading to holdups in the program.

A U.S. Navy F/A-18F Super Hornet, from the "Mighty Shrikes" of Strike Fighter Squadron (VFA) 94, flies over the U.S. Central Command area of responsibility during a mission in support of Operation Inherent Resolve, Sept. 30, 2020. VFA-94 is assigned to Carrier Air Wing 17, deployed aboard the aircraft carrier USS Nimitz (CVN 68), flagship of Nimitz Carrier Strike Group. The F/A-18F is designed to perform fighter escort, fleet air defense, suppression of enemy air defenses, air interdiction, close air support, and aerial reconnaissance. (U.S. Air Force photo by Staff Sgt. James Merriman)
Another view of an IRST-equipped U.S. Navy F/A-18F over the U.S. Central Command area of responsibility during a mission in support of Operation Inherent Resolve. U.S. Air Force photo by Staff Sgt. James Merriman Staff Sgt. James Merriman

In the past, we have looked extensively at the advantages the IRST Block II pod will bring to the Super Hornet community and the Navy’s tactical aviation branch as a whole.

The key arguments in favor of the Navy introducing an IRST capability on its Super Hornets are worth recalling.

In particular, with China identified as the ‘pacing’ military threat, such capabilities will be fundamental to any future conflict in the Pacific theater.

China is making rapid developments in stealth technology and advanced electronic warfare, two areas that make the introduction of an IRST sensor all the more compelling. These kinds of infrared sensors are immune to radar-evading stealth technology and are not affected by electromagnetic jamming and other electronic attacks.

The Chinese diamond-shaped, stealthy, heavy tactical combat aircraft design, tentatively known as the J-36, which surprisingly appeared late last year. via X

As well as being used as a targeting sensor, an IRST can also considerably enhance the flight crew’s situational air-to-air ‘picture’ in conjunction with more traditional sensors.

The delays and problems with the Navy’s IRST pod are all the more alarming considering that the Air Force has already put equivalent sensors on its F-15Cs and F-16Cs. It should be noted, however, that the reliability of the Air Force’s IRST pods isn’t entirely clear at this point.

The Legion IRST pod on a U.S. Air Force F-16:

Even the contractor-operated adversary community is increasingly flying fast jets with IRST sensors. This is before we come to potential adversaries, such as China and Russia, which operate tactical fighters such as the Su-35 and Su-30 Flanker series that incorporate IRST sensors as standard.

The Navy will be hoping that problems with its IRST pod are overcome sooner rather than later, as there’s little doubt that a system of this kind is now badly needed.

Contact the author: thomas@thewarzone.com