Where's the Su-57? The war in Ukraine is what fifth-generation fighter jets were made for, but Russia's Felon has largely been missing in action

• Russian state media has touted the Su-57 fighter jet as a formidable, fifth-generation aircraft.
• It's the type of jet that would theoretically thrive in the Ukraine war, but it's been mostly absent.
• Aviation experts and Western intel say Russia may not want to risk any reputational damage. 

Russia's air force has yet to break through Ukraine's formidable air defenses and achieve air superiority, which is somewhat surprising given that the Russians supposedly have something the Ukrainians do not — a fifth-generation fighter jet.

The high-threat environment in Ukraine, where pilots in older aircraft are having to fly low to the ground to skirt enemy radars for fear of being shot out of the sky by a surface-to-air missile, is exactly what fifth-generation stealth fighters were made for.

So where has Russia's much-touted Su-57 been all this time? 

The Su-57 — known by NATO as 'Felon' — has largely been missing in action beyond possibly firing missiles from Russian territory last year. Western intelligence and aviation experts say Russia's reluctance to employ the aircraft in combat suggests Moscow may not be confident in the jet's purported stealth capabilities and technology and likely wants to avoid any potential reputational damage that could come from losing one of these aircraft to Kyiv's surface-to-air missile systems.

"There's geopolitical reputation, but I think there's also the reputation of the Russian defense industry to consider, and how that would look to prospective buyers of this aircraft," Mike Dahm, a former US Navy intelligence officer, told Insider. 

The twin-engine Su-57 is Russia's first attempt at a fifth-generation fighter. To qualify for this designation, an aircraft must have certain features like the ability to "supercruise," or cruise at supersonic speeds, without engaging its afterburners and possess stealth capabilities that help it avoid detection, among other things. Analysts have questioned whether the Su-57 is truly fifth-gen given the apparent lack of certain necessary capabilities.

Dahm, a senior resident fellow at the Mitchell Institute for Aerospace Studies, said the advertised capabilities and aerodynamics of the Su-57 — like its turn radius, rate of climb, and agility — lend credence to the notion that the aircraft is optimized for dogfighting. However, he added, Russia is still lagging in its pursuit of the low-observable technologies that would give it a high degree of stealth. 

"The Russians haven't hit their stride in terms of production of this aircraft," he said. "There are very few of them. They're still working out bugs in this aircraft, and it is still undergoing substantial modifications."

The first Su-57 was delivered to the Russian military in 2020 and there are reportedly as many as 10 in its arsenal, with state media estimating that this figure will jump to 22 by the end of next year and increase to 76 by 2028. Russia has said that the aircraft first saw combat above Syria in 2018, as part of the country's years-long support of the Assad regime.

Then, in May 2022, Moscow's state media cited unnamed sources in reporting that the fighter jet had been used against Ukraine by firing missiles outside the range of Kyiv's air-defense systems. Russian Defense Minister Sergei Shoigu later said in an August interview that the "aircraft has shown itself brilliantly." 

Britain's defense ministry wrote in an early January intelligence update that since at least June 2022, the Russian air force has "almost certainly used" the Su-57 to carry out missions against Ukraine. "These missions have likely been limited to flying over Russian territory, launching long range air-to-surface or air-to-air missiles into Ukraine," it added.

There's not much evidence of Su-57 activity in Ukraine. But if the aircraft has been used in combat operations, it's done so very sparingly, and there are several possible explanations for why this has been the case. 

"Russia is highly likely prioritising avoiding the reputational damage, reduced export prospects, and the compromise of sensitive technology which would come from any loss" of the Su-57 over Ukraine, Britain's defense ministry said in the intelligence update. "This is symptomatic of Russia's continued risk-averse approach to employing its air force in the war."

The airspace above Ukraine remains highly contested, and neither side has been able to secure air superiority because of the sophisticated air-defense capabilities — like surface-to-air missile systems (SAMs) — that each military operates. The combat environment has led both Ukraine and Russia to be more cautious with the airpower they have available.

Still, Russian state media has touted the Su-57 as being comparable to — if not better than — American fifth-generation stealth fighters like the F-22 and F-35, and experts argue that the latter, which is intended for air-superiority and strike missions, is perfectly designed to succeed in a threat environment like the one in Ukraine.

So why is it that the Su-57 isn't doing what a true fifth-generation stealth fighter should theoretically be able to do in Ukraine? The aircraft may simply not be as capable as the Russians claim it is.

"Russian reticence to employ the Su-57 close to the frontlines despite having a huge amount to potentially gain by being able to operate more freely in the face of Ukrainian SAM systems suggests that they do not have confidence in the claimed stealth properties of the jet," Justin Bronk, an airpower and technology expert at the UK-based Royal United Services Institute (RUSI) think tank, told Insider.

The Su-57 is beset with technical issues, among them being Russia's apparent inability to put body panels on the fighter jet that are placed tightly enough together such that the radar signature is decreased. Additionally, the aircraft lacks stealth-capable engines.

Bronk said that the Su-57 is also limited by that fact that it can currently only carry an older variant of the R-77 air-to-air missile, the R-77-1, "which has folding grid fins that prevent it from being carried internally on the aircraft and hence compromises its stealth signature."

And, again, there's also the reputational — and operational — damage that the loss of a Su-57 could cause to Russian President Vladimir Putin. 

"The PR disaster of a Su-57 being shot down by Ukrainian SAM systems is clearly something that they are not prepared to risk at this stage," Bronk said. Not only would it be an embarrassment to lose one of its newest jets to an adversary it regards as inferior, but it could also hurt Russia's arms export business.

Foreign military sales are one way the Russian defense ministry supports the supply of aircraft to its air force, Dahm said. If a Su-57 failed, crashed, or was shot down over Ukraine, the reputational hit to the fighter jet could place possible foreign sales in jeopardy.

According to a 2021 Congressional Research Service report, Russia at the time was the world's second-largest exporter of arms behind the US and sold weaponry to over 45 countries — accounting for 20% of global sales since 2016. Aircraft alone made up half of that figure, according to official Russian data cited in the report. 

Russia's ongoing war in Ukraine, however, has put a clear dent in its foreign military sales. 

There's also the potential that sensitive technologies could be compromised. The Su-57 is a new aircraft and details about it, especially its internal systems, are limited, so if the fighter jet were to get shot down or crash in Ukraine, the next stop for that wreckage would be a hangar somewhere in NATO, Dahm said.

"There are certainly new Russian technologies in the Su-57 that the US and Western intelligence would be very interested to examine, allowing our air forces to develop countermeasures against whatever systems the Russians have built into the Su-57," he said.

The Su-57, meanwhile, is not the only example of a much-celebrated Russian weapon that's been, for the most part, noticeably absent from the battlefield in Ukraine. For example, Kyiv's military intelligence chief said last month that there is not "a single instance" of Moscow's new T-14 Armata tank — once feared by Western experts — being used in Ukraine.