Why the Israeli Air Force is modifying its F-35I Adir aircraft: range, electronic warfare, integration of local weapons.

The Israeli Air Force has undertaken major modifications to its F-35I Adir, a derivative of the American F-35A. Officially authorized by the United States, this reengineering aims to meet specific tactical requirements, including extended range and the addition of electronic warfare (EW) modules adapted to regional threats. These adaptations enable them, for example, to carry out direct strikes in Iran without in-flight refueling or to integrate local weapons. This technical work is being carried out in a demanding operational context: neutralization of Iranian air defenses, nuclear targets, enemy electronic jamming, etc. It gives the Israeli fighter jet a real strategic advantage, reinforced by local maintenance capabilities. This article offers a detailed analysis, divided into four parts, to examine the reasons behind these modifications, based on figures, concrete examples, and a desire to provide value to the reader.

The strategic reason for the modifications

Israel has secured a unique agreement with the United States to extensively modify its version of the F-35, known as the F-35I Adir, in order to meet strict operational requirements linked to its regional military doctrine. One of the main objectives is to ensure direct strike capability against Iran, located approximately 1,500 kilometers away, without the need for in-flight refueling. This autonomy reduces dependence on refueling aircraft, while limiting the risk of prolonged exposure to radar detection.

Another strategic imperative is to counter advanced ground-to-air systems deployed by Iran, such as the Russian-made S-300PMU-2. These defenses, equipped with long-range radars and high-performance missiles, require a high level of stealth and sophisticated electronic warfare capabilities. Israel has therefore obtained authorization to modify the original BAE AN/ASQ-239 electronic warfare suite by integrating technologies developed locally by Elbit Systems. These sensors enable precise detection, targeted jamming, and electronic countermeasures adapted to the frequencies used in the region.

Finally, maintenance operations are centralized at the Nevatim air base, without going through Lockheed Martin’s logistics. This logistical autonomy ensures better aircraft availability while reducing downtime for heavy maintenance. Although the hourly flight cost of the F-35 remains high—estimated at between €40,000 and €90,000—the ability to adapt and maintain the aircraft locally significantly enhances its operational effectiveness in a highly contested environment.

Technical modifications: autonomy and electronic warfare

Israel has made substantial structural and electronic modifications to the F-35I Adir to enhance its autonomy and electronic warfare capabilities in heavily defended environments. These modifications are designed to maximize operational effectiveness over a wide range, with sensors adapted to regional threats.

Compliant external fuel tanks

One of the priorities was to extend autonomy without sacrificing stealth. To achieve this, Israel designed compliant external fuel tanks with low radar signature. Integrated into the fuselage and covered with absorbent materials, they do not significantly alter the aircraft’s radar profile. These tanks enable a range of over 2,200 km in cruise flight, making it possible to fly to Iran and back without refueling. They are attached using pylons designed specifically to preserve the jet’s aerodynamics and electromagnetic signature.

Modular platform and onboard computing

The F-35I’s Main Mission Computer (MMC) has been reconfigured to allow the integration of local modules in a plug-and-play architecture. This technical modularity allows the addition of Israeli software, sensors, data links, and targeting systems without recompiling all of the critical US systems. This choice aims to ensure the IDF’s functional independence in adapting the aircraft to future weapons or sensors as regional threats evolve, while maintaining the airframe’s stealth performance.

Next-generation electronic warfare

The original BAE Systems AN/ASQ-239 electronic warfare system has been replaced or supplemented by a system developed by Elbit Systems. This device includes active jamming, digital decoys, and multi-spectral detection capabilities. It is designed to quickly detect and neutralize surveillance radars, infrared or electromagnetic guidance systems, and ground-to-air missile systems such as the Tor-M1 or S-300PMU-2. By providing autonomous EW coverage, the F-35I can engage in complex offensive missions without external support, even in areas saturated with enemy signals.

Integration of weapons and sensors

One of the key elements of the F-35I Adir program is the ability for Tsahal to integrate its own equipment into a platform normally locked down by the American manufacturer Lockheed Martin. Thanks to adaptations to the Main Mission Computer, Israel can insert locally developed weapons and sensors directly into the aircraft’s digital environment, while maintaining compatibility with the original mission software. This greatly enhances the aircraft’s tactical flexibility in the regional context.

Local weapons

Israel designed the F-35I to carry air-to-air missiles and domestically manufactured guided bombs in its internal bays while maintaining its low radar signature. Although the exact list of these weapons remains confidential, tests have been conducted since 2020 with local munitions. It is highly likely that missiles such as the Python-5 or Derby radar-guided missiles will be integrated, alongside SPICE-1000 or SPICE-2000 guided bombs, capable of striking targets with meter-level accuracy at ranges of over 100 kilometers. Integration into the fuselage avoids increasing drag or radar signature, which would be the case with external pylons.

Additional sensors

Israel also plans to add optical and electro-optical pods, such as the Rafael Litening 5, for more specific air-to-ground missions than those permitted by the original US EOTS (Electro-Optical Targeting System). The Litening 5 offers more accurate detection of moving targets and identification capabilities better suited to operations in complex environments such as urban or semi-mountainous areas.

Data link system

Finally, the Israeli datalink, developed for the F-35I, bypasses the MADL (Multifunction Advanced Datalink) data link imposed by the United States. This local system allows the F-35I to communicate in real time with other Israeli aircraft (F-15I Ra’am, F-16I Sufa), ground control systems, MALE drones, and missile defense batteries such as David’s Sling. This cross-platform compatibility enhances the F-35I’s integration into the Israeli Air Force’s network-centric operations, ensuring tactical data transmission without US format constraints.

Operational results and challenges

Feedback from the field

The modifications made to the F-35I Adir have not remained theoretical. They have been tested repeatedly in real combat situations. Since 2021, the aircraft have participated in the interception of Iranian drones approaching Israeli borders, demonstrating their long-range detection and interception capabilities. In 2023, the F-35Is were used in missions to neutralize ballistic missiles in flight, including missiles launched from southern Lebanon and Syria targeting northern Israeli territory.

The most significant operations took place between 2024 and 2025, with deep strikes on sensitive infrastructure in Iran. These raids, carried out at very long range, involved penetrating areas monitored by S-300PMU-2 radars and protected by medium-range surface-to-air batteries. The F-35I proved its ability to pass through these defenses, engage targets, and then leave without being detected. The IDF claims that more than 100 military targets were neutralized, including nuclear research sites and drone and missile warehouses.

Costs and availability

The operational cost of the F-35I remains high, with estimates ranging from €40,000 to €41,000 per flight hour. This cost includes fuel consumption, maintenance, spare parts, and technical personnel costs. However, Israel’s decision to carry out all maintenance at the Nevatim base reduces response times, increases aircraft availability and limits dependence on the US manufacturer for heavy logistics. This independence comes at a price, but it ensures a level of tactical responsiveness that is difficult to achieve in other armies equipped with the F-35.

Limitations

The main limitation of the fleet at present is its small size. Of the 50 aircraft ordered, only 36 to 39 will be operational in 2025. The rest are still being delivered or modified. This number limits Israel’s ability to conduct saturation operations or engage on multiple fronts simultaneously. In addition, the development of passive detection technologies (long-range IRST sensors, low-wave radar networks) by Iran and its allies could, in the medium term, reduce the stealth advantage of the F-35I. Finally, maintaining the high technological level of these aircraft requires rigorous budgetary monitoring and a solid industrial capacity to integrate future software and hardware upgrades without depending on the US schedule.

These modifications make the F-35I Adir unique. The addition of external fuel tanks, the Elbit electronic warfare platform, the local datalink, and the integration of Israeli weapons make this fighter jet a holistic system, tailored for strikes in highly defended areas of Iran. These adaptations enable long, autonomous, stealthy flights that are perfectly connected to the Israeli military infrastructure. By combining an advanced tactical approach with cutting-edge aeronautical engineering, the F-35 Adir is positioned as a decisive strategic tool. However, budgetary and industrial challenges, as well as the evolution of enemy defenses, now require constant vigilance to maintain its effectiveness.