U.S. Air Force is hoping to integrate a new, advanced chaff countermeasure onto its F-35A Joint Strike Fighters next year, according to a report. The cartridges, which release radar reflective material to blind and confuse enemy aircraft and air defenses, are a staple across many of the service's other combat aircraft, but have been curiously absent from the stealthy F-35's otherwise extensive defensive suite. Aviation Week's Defense Editor Steve Trimble, a good friend of The War Zone, was first to spot the detail on Sept. 9, 2019. The Air Force included the information about the new chaff cartridge, known presently as the ARM-210, in a draft environmental impact statement, dated August 2019, regarding the basing of F-35s at various Air National Guard facilities. The report includes a host of information on how the aircraft might impact their surrounding environments, including the potential release of countermeasures, such as infrared decoy flares and chaff.

"The ARM-210 chaff proposed for use by the F-35A is currently unavailable and undergoing operational testing," according to the environmental review. "It is expected to be available for use in 2020." It is unclear whether this applies to the U.S. Marine Corps F-35B or U.S. Navy F-35C variants, as well, or any of the three variants in service with foreign air forces. The F-35's use or potential use of chaff has long been something of a debate, in general. Recent U.S. military budget documents and other sources make no mention of it among the aircraft's expendable countermeasures – flares and towed decoys – which had suggested that it was, indeed, a capability the Joint Strike Fighter lacked and might not necessarily have needed given its stealthy design.

Lockheed Martin An image showing the general layout of the defensive systems on a Marine Corps F-35B. The general location of the infrared countermeasures (IRCM) dispensers, as well as Radiofrequency Countermeasures (RFCM) dispenser, loaded with flares and towed decoys respectively, are the same as on the F-35A. The IRCM dispensers will likely be used to fire the new ARM-210 chaff cartridges in the future.

However, F-35 simulators have included the ability to replicate this functionality, according to Trimble. He also noted that a briefing in 2018 from U.S. Navy Vice Admiral Mathias Winter, then head of the F-35 Joint Program Office (JPO), had included a reference to "advanced chaff" as being part of the still-in-development Block 4 upgrades for the Joint Strike Fighters.

The ongoing testing of the ARM-210 now confirms that at least the Air Force plans to integrate chaff into its F-35As in the near future. This cartridge's specifications, and how it differs from RR-180 and RR-188 types the service already has as a countermeasure option for other combat aircraft, is unclear. "ARM-210 chaff is similar to the RR-180 and RR-188 chaff currently in use by the F-16, F-15, and A-10 aircraft proposed for replacement [with the F-35]," the environmental impact report says, without offering any other details. "A bundle of chaff consists of approximately 5 to 5.6 million fibers that are cut to reflect radar signals, and when dispensed from aircraft, form an electronic 'cloud' that breaks the radar signal and temporarily hides the maneuvering aircraft from radar detection," it says more generally. Chaff, which dates back to World War II, originally consisted of aluminum strips cut to various lengths. More modern examples, use metallicized synthetic fibers, which help them hang in the air longer, offering more persistent effects. The Armtec RR-188, for example, uses bundles of aluminum-coated silica fibers. There have been a number of chaff releases within the United States in the past few years as part of training exercises that have highlighted just how long-lasting and far-ranging the clouds can become depending on release altitude and environmental factors. The size and composition of the fibers are directly connected to what radar bands the chaff affects, which can make them particularly effective against specific threats.

USN See-through display examples of the US Navy RR-129 chaff cartridge, at bottom, and RR-144 at top, as well as loose fibers, at right. This gives a good general sense of the payloads inside the RR-180s and -188s.

The ARM-210 designation would suggest that the new cartridge is another Armtec product. The company, a division of Esterline, which is now itself a subsidiary of TransDigm Group, uses this nomenclature internally for its countermeasure products, which include both chaff and flares. Armtec's RR-180s and -188s are already significant improvements over the older RR-170-series. These newer cartridges fit into the same one-inch-by-one-inch slots in U.S. military countermeasures dispensers, but hold two self-contained chaff payloads that fire separately. Each one provides the same level of defense as a single RR-170. What this means is that the RR-180s and -188s effectively double the amount of chaff an aircraft can carry in the same dispenser. The exact construction of the chaff payload in the ARM-210 could be even more effective and long-lasting. At the same time, a 2014 brochure from Esterline interestingly says that the company offered "Specialized tactical and training variants developed for F-22 and F-35 platforms." It's not clear whether this meant that the Air Force and other F-35 operators had intended to employ RR-180s or -188s on their jets or if the ARM-210 has been in development at least that long.

Esterline Part of a 2014 Esterline brochure that mentions Armtec chaff cartridges for the F-22 and the F-35.