Earlier this month, the Israeli Air Force announced that its F-35I Adir stealth fighters have repeatedly flown in what’s known as “Beast Mode” during combat operations, a configuration that loads the aircraft with a full complement of weapons, including external bombs mounted under its wings.
Israel's F-35I Adirs feature US-enhanced 'Gaza tasks brains'
Photo credit: Defense Here
This setup, detailed in a statement from the Israeli military, sacrifices the jet’s stealth capabilities for increased firepower. The modification allowing this mode stems from a collaboration between Israel’s internal Flight Test Center, Lockheed Martin, and the Pentagon’s F-35 program office, which adapted the aircraft—known locally as the “Adir,” or “Mighty One”—to carry precision-guided JDAM bombs externally.
According to posts on X from the Israeli Air Force, this makes the Adir the only F-35 variant worldwide to conduct strikes with such a design. Since October 2023, these jets have logged over 15,000 operational flight hours, targeting sites in Iran, Yemen, and Lebanon, though specific mission details remain undisclosed by the military.
The announcement came amid a period of heightened activity for the Israeli Air Force, which has relied heavily on its F-35I fleet to address regional threats. The service reported that three new Adir jets arrived at Nevatim Air Base last week, joining the 116th Squadron and bringing Israel’s total F-35 count to 42.
This expansion follows a pattern of steady procurement, with Israel initially ordering 50 of the fifth-generation fighters from Lockheed Martin and later adding 25 more in 2023. The Adirs have been active across multiple fronts, engaging targets over significant distances, including long-range strikes in Yemen and operations closer to home in Lebanon.
While the military has not specified which missions utilized Beast Mode, the capability underscores a shift in how Israel employs its stealth fighters, prioritizing payload over invisibility to radar in certain scenarios.
Beast Mode represents a significant departure from the F-35’s standard operating profile. Typically, the aircraft is designed to carry weapons internally—up to 5,700 pounds in its two bays—to maintain a low radar cross-section, a hallmark of its stealth design.
In this configuration, it can deploy air-to-air missiles like the AIM-120 AMRAAM or precision bombs such as the GBU-31 JDAM, all while evading enemy detection. Beast Mode, however, pushes the jet’s capacity to 18,000 pounds by adding external hardpoints, allowing it to carry larger munitions or additional ordnance like the 2,000-pound GBU-31 bombs seen in recent operations.
This comes at a cost: mounting weapons externally increases the aircraft’s visibility on radar, negating much of its stealth advantage. The Israeli Air Force has not clarified why it opted for this approach in specific strikes, but analysts suggest it may reflect a need for greater destructive power against hardened or dispersed targets, where stealth is less critical than sheer payload.
The mechanics of Beast Mode are rooted in the F-35’s inherent flexibility. Lockheed Martin engineered the jet with six external weapon stations—three per wing—that can be activated when stealth is not a priority.
In this setup, the Adir can carry a mix of munitions, including JDAMs, which convert unguided bombs into GPS-guided weapons capable of striking targets up to 15 miles away when dropped from high altitude. Posts on X from aviation enthusiasts have highlighted images of an F-35I loaded with four 2,000-pound JDAMs and an AIM-120 missile, illustrating the kind of firepower this mode enables.
The Israeli military’s statement credits the Flight Test Center’s work with Lockheed Martin and the Pentagon for making this adaptation possible, a process that unfolded during the ongoing conflict that began in October 2023. This collaboration has allowed Israel to tailor the jet to its operational demands, flexibility not extended to most F-35 operators.
What sets the Israeli F-35I apart from its American counterparts is the degree of customization Israel has achieved. Unlike the U.S. Air Force’s F-35A, which adheres strictly to Lockheed Martin’s baseline design and U.S.-produced weaponry, the Adir integrates Israeli-made systems and munitions.
The aircraft features domestically developed electronic warfare suites, produced by companies like Elbit Systems, and can carry Israeli-guided bombs and air-to-air missiles in its internal bays, according to a 2010 Aviation Week report. This independence stems from a unique arrangement with the United States, which has granted Israel unprecedented autonomy over its F-35 fleet.
While most nations in the F-35 program—over 20 countries have ordered the jet—rely on American maintenance and standardized equipment, Israel conducts its own depot-level repairs and software modifications, as noted in posts on X by defense observers like @clashreport. This freedom allows the Israeli Air Force to adapt the Adir to regional threats, such as Iranian proxies in Gaza and Lebanon, without waiting for U.S. approval.
The U.S. decision to permit this customization reflects a strategic partnership rooted in Israel’s security needs. As a “security cooperation participant” rather than a full member of the F-35 Joint Program Office, Israel doesn’t receive the same technical oversight as nations like the UK or Japan, per a Congressional Research Service report.
Instead, it negotiates directly with Lockheed Martin and the Pentagon to integrate its technology. This includes not just weapons but also advanced sensors and countermeasures, some of which remain classified.
Analysts suggest that Washington tolerates this arrangement because Israel’s combat experience—starting with the F-35’s first confirmed use in Syria in 2018—provides valuable data for the broader program. The Adir’s ability to operate in high-threat environments, like its interception of a Houthi cruise missile in 2023, showcases capabilities that benefit U.S. planners, even if they diverge from American doctrine.
This divergence raises questions about how the Adir operates in contested airspace, particularly near Russian forces in Syria. Since 2015, Russia has deployed S-400 air defense systems in the country, capable of detecting and engaging targets at ranges up to 250 miles. The S-400’s radar could theoretically spot an F-35 in Beast Mode, given its increased visibility, posing a risk to Israeli missions over Syria or Lebanon.
Some analysts hypothesize that Israel and Russia might have an informal understanding to avoid direct confrontation. During Israel’s campaign against Iranian targets in Syria, which intensified after 2018, there have been no confirmed instances of Russian S-400s firing on Israeli jets, despite their proximity.
A 2021 report from the Alma Research Center noted that Israel often notifies Russia in advance of strikes to prevent escalation, a practice dubbed the “deconfliction mechanism” by military observers.
Evidence of such coordination remains circumstantial. In May 2018, when Israel first used the F-35 in combat, Air Force Commander Major General Amikam Norkin said the jets struck targets in Syria without specifying Russian reactions. Subsequent operations, including a 2023 strike on Iranian weapon sites near Aleppo, unfolded without reported S-400 interference, according to The Jerusalem Post.
Experts like Air Marshal Anil Khosla, quoted in EurAsian Times, argue that Beast Mode would only be viable in high-risk areas like Syria after enemy defenses are neutralized—potentially with Russian acquiescence. However, no official statements from Moscow or Jerusalem confirm this arrangement. The lack of downed F-35s suggests either exceptional Israeli tactics or a tacit agreement, but definitive proof is elusive.
The broader context of Adir’s use offers further insight. Since the war with Hamas broke out in October 2023, the Israeli Air Force has flown thousands of sorties, targeting Hezbollah in Lebanon, Houthi militants in Yemen, and military sites in Iran.
A notable example came last July, when F-35Is struck Hodeidah port in Yemen, over 1,000 miles from Israel, in retaliation for a Houthi drone attack on Tel Aviv. The jets reportedly used external fuel tanks—another Israeli modification—to extend their range, a capability detailed by The Aviationist.
In Iran, the Adirs hit air defense systems during Operation Day of Repentance in October 2024, per The National Interest, showcasing their reach and firepower even in Beast Mode.
These missions highlight Adir’s evolving role. While stealth remains a core advantage—demonstrated in its 2021 downing of Iranian drones, per IDF statements—the shift to Beast Mode reflects a pragmatic trade-off.
Against foes like Hamas, which lack advanced air defenses, stealth is less critical than overwhelming force. In contrast, operations near Russian or Iranian systems demand careful planning, possibly leveraging diplomacy or electronic jamming from Israel’s custom suites. The Adir’s 15,000-plus flight hours underscore its workload, a figure unmatched by most F-35 operators, according to the Israeli military.
As Israel’s F-35 fleet grows—plans call for 75 jets by decade’s end, per Kan News—the Beast Mode adaptation could become more common. The aircraft’s ability to switch between stealth and high-payload configurations offers flexibility, though it raises questions about future encounters with sophisticated defenses.
For now, the Adir remains a cornerstone of Israel’s strategy, its unique features shaped by a blend of American engineering and Israeli ingenuity, tested in real-world conditions that few other air forces can match.
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