Russia’s Su-35 fighter jets are increasingly flying with longer-range air-to-air missiles that make them a potentially greater threat to NATO air operations, a leading airpower expert assessed in a recent report.
Justin Bronk, a researcher at the UK-based Royal United Services Institute, said in his assessment of Russian air power that regularly arming Su-35 and Su-30SM2 jets with R-37M missiles “has significantly contributed to increasing the threat that they can theoretically pose to NATO air operations.”
The R-37M missile, which NATO calls the RS-AA-13, is “much more capable at long range” than the R-77-1 missiles the Su-35 had previously relied on, Bronk told Business Insider in a discussion of his recent report.
R-77-1 missiles have a range of about 62 miles, while R-37M missiles are understood to have a range of around 200 miles. Real-world kills at range depend on a mix of factors, but reach still matters.
Bronk told Business Insider that the longer-range R-37M missiles had been “very much a specialist weapon” for a limited selection of Russian jets. But “now you see absolutely routine employment” of the weapon on Russia’s Su-35S.
The Su-35 fighter is “the primary air superiority aircraft for the Russians,” he added. The jet is key for Russia’s air force, with the UK Ministry of Defence in 2023 describing it as Russia’s “most advanced combat jet in widespread service.”
Bronk told Business Insider that for the NATO alliance, the regular arming of Su-35s and Su-30SM2s with the R-37M is “a problem” because it puts “more credible long-range air-to-air missiles at play from the Russian side.”
Those missiles used to be contained within a smaller part of the force, mainly Russia’s MiG-31s. Now, Bronk said, having them on more jets “is obviously a significant growth in the potential threat that they can pose to NATO aircraft in a direct conflict.”
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Additionally, he said, Russia’s Su-35 crews are “generally more highly selected, better trained, more capable than the crews on the MiG-31s.” Russia’s better pilots tend to fly its top jets, and those will be the pilots operating these missiles.
Having them routinely carry long-range air-to-air missiles, rather than the “really pretty limited” R77-1 that they used to carry, Bronk said, “is a significant shift.”
A missile with a longer reach
The R-37M’s combat effectiveness has been spotlighted by Russia’s full-scale invasion of Ukraine, which began in February 2022.
Late that year, a RUSI report said the R-37M, combined with Russia’s MiG-31BM interceptor aircraft, was proving to be “highly effective and difficult for Ukrainian pilots to evade due to its speed, very long range, and specialized seeker for low-altitude targets.”
At that time, it said Russia was just starting to put them on Su-35S jets.
A newer report from RUSI in November highlighted how much more the R-37M missile was being used, saying that this missile “in particular, has been used to destroy several Ukrainian aircraft at long range,” including one kill recorded at more than 109 miles.
“This is significantly beyond the engagement range of most NATO air-to-air munitions,” the report said. But it also said that the missiles’ success was “heavily determined by Ukraine’s lack of effective radar warning receivers,” something NATO has fielded far more robustly across its air forces.
The Su-35 threat
Making the Su-35 more powerful is a big move for Russia. In 2022, analysts at the RAND Corporation described the Su-35 as Russia’s “signature heavy fighter.”
Ukraine has shot down multiple Su-35s in its fight against Russia’s invasion, but Bronk said that despite reported losses, the fleet has “marginally increased since the start of the full-scale war.”
He estimated that in late 2020, Russia had about 90 Su-35s. Between eight and 10 have been lost in combat or accidents, he said, but 55 to 60 new aircraft have since been delivered — leaving Russia with roughly 135 to 140 Su-35s overall, a net increase despite the attrition.
Bronk’s analysis was based on interviews with Western air forces and ministries, data from Ukraine’s armed forces, and open-source information.
He said that the Russian air force has gained so much valuable combat experience against Ukraine that its air force is now “a significantly more capable potential threat for Western air forces than it was in 2022.”
He said that in air-to-air combat, where Russian aircraft take on Western ones, the West still has a strong advantage, but longer-range air-to-air missiles complicate the picture.
And any fight would not only be in the air. The West would face not only Russia’s air force but also its vast ground-based air defense network, which the war has also made more formidable.
Bronk told Business Insider that Su-35 crews are typically “much better at working with the ground-based air defenses,” meaning the jets can operate more effectively under the umbrella of Russian surface-to-air missile systems and are therefore “more credible as an air-to-air threat.”
He said that the improvement of those ground-based defenses throughout the war — combined with the fielding of more powerful missiles on Su-35s that are increasingly integrated with them — is one reason why Russian airpower “represents a greater threat to Western air power capabilities in Europe” than it did before the full-scale invasion.
