Category Archives: Air Forces

How Good Is Russian Electronic Warfare? (Part I)

There’s been a slow accumulation of hysteria about this in the West since Russia’s invasion of Crimea and eastern Ukraine.  Naturally, the Russians didn’t sit on their hands while the U.S. focused exclusively on fighting insurgents and IEDs for more than a decade.

But how much of the Russian EW threat is real and how much imagined?

Let’s turn to Aleksey Ramm who grappled with the question in a two-part article for VPK.  Photos were added along with the translation.

“Electronic Warfare — Myths and Facts — Part I”

“How unique are Russian Army EW systems?”

“Recently Russian electronic warfare systems have acquired the aura of some kind of super weapon, capable, according to average opinion, of causing panic in the probable enemy with the flip of just one switch.”

“It all began with the flight of an Su-24 frontal bomber over the American destroyer ‘Donald Cook’ described in practically all Russian media, during which the Russian aircraft supposedly employed its newest ‘Khibiny’ system.  Its effect on the ship’s electronic equipment almost caused panic leading to the mass resignation of sailors and officers from the ‘Cook.’  Later a photograph appeared on the Internet allegedly of a memorial coin (according to other data — a medal), noting this historic overflight, and on its back side was inscribed ‘Lesson of Peace.’”

“Why did ‘Khibiny’ eat up ‘Cook’?”

“The story of the ‘Donald Cook’ hadn’t quieted down when on 4 August of this year the blog published an article Electronic Warfare: What US Army Can Learn From Ukraine (‘Radioelectronic Warfare:  What Lessons the US Army Can Take From the Ukrainian Conflict’) by author Joe Gould (Dzho Guld), where it’s asserted that the Russian Armed Forces have made a significant jump in the realm not only of developing electronic warfare systems, but in their use, that demonstrates, in the author’s opinion, that a lag has started to take shape for the American military on this issue.”

“We can’t forget that one of the leading developers and producers of Russian electronic warfare systems — Kontsern Radioelectronic Technologies (KRET) is currently conducting an aggressive PR campaign supporting its products.  It’s sufficient to recall that in the media more and more often we hear headlines:  ‘KRET has presented a unique jammer for long-range radar surveillance aircraft,’ ‘Jamming system reliably defends troops from enemy artillery fire’ and the like.”

“Thanks to such popularity of EW it’s not only specialized publications, but even the general media announcing that EW equipment ‘Krasukha-2,’ ‘Krasukha-4,’ ‘Rychag,’ ‘Infauna’ is entering the Russian Army inventory…  And to be honest, it’s fairly difficult even for a specialist to sort things out in this flow of names.”

Krasukha-2 (photo:

Krasukha-2 (photo:

“But how effective are the Russian electronic warfare systems being presented and how well is EW organized?  We’ll try to answer these questions.”

“Priority on EW”

“The following fact attests that Russia’s military-political leadership is paying close attention to the development of electronic warfare systems:  the 15th Independent Electronic Warfare Brigade (Supreme Main Command) appeared back in April 2009.  It’s notable that according to some data — besides the 15th obr REB there are only two brigades carrying the title Supreme Main Command in the RF Armed Forces (one engineering and one RKhBZ), but according to other data — it is still the only such brigade of the VGK¹ in the Russian Army.”

“Currently the 15th Brigade, which was earlier based in the Tula oblast town of Novomoskovsk and received its combat banner in accordance with an April 2009 presidential decree, has transferred to [the city of] Tula.  We should note that this formation has been outfitted with the most modern electronic warfare systems, including the still secret [sic] communications suppression system ‘Murmansk-BN’ and ‘Leyer-3’ aerial jamming system.”

Murmansk-BN (photo:

Murmansk-BN (photo:

“Besides the brigade of the Supreme Main Command, since 2009 independent electronic warfare centers have been formed in every military district.  True, the majority of them are currently being reformed into independent electronic warfare brigades.  The exception consists only of the recently formed EW center in the Crimea, subordinate to the Black Sea Fleet command.”

Leyer-3 Mounted on Orlan-10 UAV (photo:

Leyer-3 Mounted on Orlan-10 UAV (photo:

“Besides brigades, in every district there are also independent battalions, for example, the independent EW battalion subordinate to the Central Military District command and based in the city of Engels in Saratov oblast.  We should note that, it’s most probable that the mission of such battalions is covering particularly important civilian and military facilities.”

“Strategic battalions equipped with the above mentioned ‘Murmansk,’ and also tactical ones — with ‘Infauna’ systems on a BTR base, R-330Zh ‘Zhitel’ and R-934 jamming stations go into EW brigades and centers.  Besides two battalions in brigades and centers there are also independent companies — one equipped with so-called [anti-]aircraft systems, that is ‘Krasukha-2’ and ‘Krasukha-4’ systems, and a company with aforementioned ‘Leyer-3s.’”

“The recently established Aerospace Forces are also receiving modern electronic warfare systems, we are talking in particular about such equipment as ‘Khibiny’ systems which have recently become almost legendary and are on Su-34 frontal bombers, but also  about Mi-8 helicopters equipped with ‘Rychag’  stations.  Also recently the Russian Air Forces’ aircraft inventory has gotten some jamming source based on the Il-18 — Il-22 ‘Porubshchik.’”

Mi-8MTPR-1 with Rychag EW System (photo:

Mi-8MTPR-1 with Rychag EW System (photo:

“‘Krasukha,’ ‘Murmansk’ and strong secrets”

“The most secret system in the entire Russian EW arsenal until recently was the ‘Krasukha-2’ jammer, though, currently first place in this nomination has gone to communications suppression station ‘Murmansk-BN,’ supposedly capable of jamming more than 20 frequencies at a range up to 5,000 kilometers.  However, there is no reliable confirmation that the newest system has such characteristics.”

“Judging by existing photographs of ‘Murmansk’ in open sources (several 4-axle increased mobility trucks with tall masts), where beside the main antennas characteristic low-frequency whip antennas are visible, it’s possible to suppose that this system is capable of jamming signals in wavelengths from 200 to 500 MHz.”

“The main problem of such a system, most likely, is that, to achieve the announced range, the signal must reflect off the ionosphere and therefore it is influenced heavily by atmospheric disturbances, which, undoubtedly, affect the operation of ‘Murmansk.’”

“At the Moscow Aerospace Show [MAKS] last year, KRET officially presented the 1L269 ‘Krasukha-2’ system for jamming long-range radar surveillance aircraft (first and foremost American E-3 ‘AWACS’ aircraft) in its static exhibit.  It’s notable that, in the words of the concern’s leadership, this system can jam ‘AWACS’ at ranges of several hundred kilometers.”

“Still, ‘Krasukha’ continues the line of development of the ‘Pelena’ and ‘Pelena-1’ systems worked out back in the 1980s by Rostov NII [scientific-research institute] ‘Gradient.’  A very simple decision put forth by then-director of ‘Gradient,’ but later general designer of the EW department in the USSR Yuriy Perunov underpinned the idea of these items:  the signal of the jamming station must exceed the power of the signal which it is supposed to jam by 30 decibels.”

“Judging by the information we have, it’s very difficult to suppress a target like the E-3 ‘AWACS’ since its radars have more than 30 tunable frequencies which are constantly changing during operations. Therefore, Yuriy Perunov in his day proposed that the most optimal decision would be suppression of entire bands with powerful, focused noise jamming.”

“However, such a decision has serious shortcomings — ‘Pelena’ / ‘Krasukha’ jamming covers only one direction, but the aircraft flies a route, and the effect of the equipment on ‘AWACS’ will be quite limited in duration.  And if there are already two DRLO [long-range radar surveillance] aircraft operating in the area, then even accounting for jamming during the overlap of the particular aircraft E-3 operators will still be able to receive the necessary information.”

“Powerful noise jamming will not only be detected by the radar reconnaissance means of the probable enemy, but will also be a good target for anti-radiation missiles.”

“All these problems were well-known to the developers of ‘Pelena’ from the very beginning, therefore the more modern ‘Krasukha’ became highly mobile to allow it to get away quickly from a strike, but also at the same time to get into a better position to deliver electromagnetic suppression.  It’s possible that not one, but several stations constantly changing position will be used against DRLO aircraft.”

“But ‘Krasukha-2’ is not altogether such universal equipment capable of jamming numerous radars as it is fashionable to believe.  It cannot simultaneously jam both E-8 ‘AWACS’ and E-2 ‘Hawkeye,’ since a jamming station suppressing only the required band of very distinct frequencies for DRLO aircraft radars will be needed for each type of DRLO aircraft.”

“It’s notable that work on ‘Krasukha-2’ began back in 1996 and was completed only in 2011.”

“The ‘+30 dB’ idea is used in yet one more of the newest developments of VNII ‘Gradient’ — 1RL257 ‘Krasukha-4,’ which is at present being actively placed in EW brigades and independent battalions and is designated for suppression of air-based radars, including not only those on fighters and fighter-bombers, but also on E-8 and U-2 reconnaissance aircraft.  True, there are doubts about the effectiveness of ‘Krasukha’ against the ASARS-2 radar at a U-2 altitude, since, judging by the available data, its signal is not only sufficiently complex, but still also noise-like.”

“In the opinion of developers and the military, under certain conditions, the 1RL257 can even jam warhead seekers of AIM-120 AMRAAM ‘air-to-air’ missiles, and also the command and control radars of the ‘Patriot’ surface-to-air missile system.”

“As in the case of ‘Krasukha-2,’ ‘Krasukha-4’ is not a completely original item, but the continuation of a line of jamming equipment in the SPN-30 family, on which work began at the end of the 1960s.  The new station uses not only the concept of the old ‘30s,’ but also, undoubtedly, some of the technical decisions applied in it.  Work on the 1RL257 began in 1994 and was completed in 2011.”

“The ‘Avtobaza’ system also thanks firstly to the Russian media has become together with ‘Khibiny’ some kind of super weapon to the casual observer, knocking down any drone with jamming.  In particular, victory over the American UAV RQ-170 is being ascribed to this system.  At the same time, ‘Avtobaza’ itself, and also the recently accepted into the Defense Ministry inventory ‘Moskva’ system resolve completely different missions — they conduct electronic reconnaissance, they provide target designation for an electronic warfare system and are the command post of an EW battalion (company).  It is understood that ‘Avtobaza’ had a sufficiently tangential relationship to the landing of the American UAV in Iran.”

“‘Moskva’ which is currently entering the force is the continuation of a line of systems of command, control, and reconnaissance of which ‘Mauzer-1,’ adopted into the inventory in the 1970s, is considered the beginning.  In the composition of the new system, there are two vehicles — a reconnaissance station, which detects and classifies types of radiation, their direction, signal power, and also a command post from which data is automatically transmitted to subordinate EW stations.”

“According to the thinking of the Russian military and EW developers, ‘Moskva’ allows for covertly determining the situation and delivering surprise electronic suppression on the enemy’s forces and equipment.  If the system conducts electronic reconnaissance in passive mode, then it forwards commands on radio channels and the enemy can intercept them in certain conditions.  In such a situation, it isn’t even necessary to decode the signals, it’s sufficient to detect the radio traffic and this reveals the presence of each EW battalion (company).”

“Muting satellites”

“Besides battle with the enemy’s aviation means, Russian EW developers devote great attention to suppressing the enemy’s radio traffic, and also muting GPS signals.”

“Developed and produced by Kontsern ‘Sozvezdiye,’ the most well-known silencer of satellite navigation is the R-330Zh ‘Zhitel’ system.  NTTs REB, whose item R-340RP is already being supplied to Russia’s Defense Ministry sub-units, also proposed a sufficiently original solution.  Small diameter jamming transmitters, whose signal is amplified by the antenna array, are placed on civilian cell phone towers.”

“Not just the media, but also some specialists assert that it is practically impossible to mute the GPS signal.  But in Russia technical solutions for ‘turning off’ satellite navigation appeared at the beginning of the 2000s.”

“In the GPS system there is the ‘bearing frequency’ concept.  At the basis of the system lies the transmission of the elementary signal from the satellite to the transmitter, therefore the smallest turning off from the assigned frequency even by milliseconds will lead to a loss of accuracy.  The transmission of the signal goes in a sufficiently narrow band, according to open data — 1575.42 MHz and 1227.60 MHz, and this is the bearing frequency. Therefore modern jammers are focused directly at blocking it which, taking into account the narrowness of the bearing frequency and possession of a sufficiently powerful noise jammer, to silence it does not constitute a special effort.”



“The ‘Leyer-3’ system with an electronic reconnaissance vehicle on a ‘Tigr’ base, but also several ‘Orlan-10’ pilotless aircraft equipped with dispensable jamming transmitters capable of suppressing not only radio but also cell phones, is a particularly interesting solution in the area of suppressing the probable enemy’s radio traffic.   The ‘Infauna’ RB-531B system produced by Kontsern ‘Sozvezdiye’ fulfills similar missions but without the use of drones.”


¹The practice of holding some forces as reserves of the Supreme CINC dates to the Great Patriotic War (WWII) if not earlier.  The VDV and LRA are both still specified as belonging to the VGK.

Not Enough Men or Transports

Il-76 Transport Landing (photo: Kommersant / Anatoliy Zhdanov)

Il-76 Transport Landing (photo: Kommersant / Anatoliy Zhdanov)

Another large-scale Russian military “surprise inspection” has concluded, and military commentator Ilya Kramnik has placed it, and other exercises, into perspective for

Interpreted as a prologue to war in Europe by some, the Kremlin-directed “surprise inspections” are the logical continuation of a process in recent years.  It is the process of developing strategic mobility through deployment exercises, according to Kramnik.

The latest six-day “surprise inspection” focused on deploying and redeploying forces in Russia’s Arctic regions, but President Vladimir Putin expanded it into a nation-wide exercise.

Kramnik focuses his analysis first on the Kaliningrad exclave.  Russia has practiced its defense of this region since the mid-2000s on an expanding scale. But the first large-scale drill in Kaliningrad, Kramnik says, was Zapad-2009.

Kaliningrad is where the pattern of special attention to troop mobility developed. In “surprise inspections,” military units from almost every armed service and branch were delivered by ground, rail, sea, or air transport to unfamiliar ranges in that region to conduct training missions.

The pattern has repeated in each of Russia’s “strategic directions.” Although Kramnik doesn’t describe it as such, it is, in effect, the establishment of expeditionary forces within the Russian military intended for internal transfer and use on any of Russia’s borders (or beyond them).  

If mobility questions play a key role in Kaliningrad, Kramnik continues, they are dominant when it comes to the Arctic.  All Arctic deployments depend on Navy and Air Forces transport capabilities.  Then he writes:

“It relies first and foremost on reestablishment of infrastructure which supports, if necessary, the redeployment [переброска] of troops by sea and by air and not requiring large numbers of personnel for daily service and security.  13 airfields, radar stations, repaired ports and other facilities allow forces to return quickly ‘in a threatening period.’  And to control the surrounding sea and air space a rather sufficiently compact grouping based here on a permanent basis.”

Kramnik concludes that Russia is confronting its weakness — armed forces not large enough to garrison its immense territory.  This increased attention to strategic maneuver is a means to compensate for an insufficient number of troops.  He takes a comment from Viktor Murakhovskiy:

“Today we don’t have a single self-sufficient grouping on any of our [strategic] directions.  This is the main reason for the great attention the Armed Forces leadership allocates to the potential for redeploying forces.”

Mobility, guaranteed by a developed railroad network, and in distant and isolated TVDs by the world’s second largest inventory of military-transport aviation, should support the potential for Russia, if necessary, to “swing the pendulum” — effectively maneuvering forces between different TVDs, Kramnik writes.  The capacity provided by the civilian airlines and fleet can also add to this.

But besides men, Russia also lacks enough transport aircraft.  

Kramnik writes that while attention has gone to constructing and reconstructing airfields and finding personnel to service them, the VTA’s order-of-battle is in critical condition, especially in terms of light and medium transports.  The average age of the An-26 inventory is nearly 35 years; the An-12 more than 45 years.

Events of the last year in Ukraine ended what were already difficult talks with Kyiv about building the An-70 and restarting production of the An-124.  Meanwhile, much of the Antonov Design Bureau’s competence has degraded, according to CAST Deputy Director Konstantin Makiyenko.

So today, Kramnik says, Russia has at its disposal only one serial VTA aircraft — the modernized Il-76, developed 40 years ago with serious limits on the weight and dimensions of military equipment it can deliver.  It will be supplemented by the Il-112 (light) and Il-214 (medium) transports, and by a “future aviation system transport aviation” or PAK TA.

The very same reported PAK TA that generated hysterical press here, then here, and here by promising to land an entire armored division of new Russian T-14 / Armata tanks overnight, anywhere in the world.  From an aircraft industry at pains to duplicate large but old designs like Antonov’s?  Obviously, a sudden outbreak of irrational Soviet-style giantism.

In the end, Kramnik concludes that VTA needs a high priority or Russia will have trouble moving combat capable groupings to the Arctic and Far East.  New aerial tankers are needed as well.

Aerospace Forces

At some point, probably next summer, the Air Forces (VVS) will cease being one of Russia’s three armed services.  The Aerospace Forces (VKS or ВКС) will take their place.  The Aerospace Defense Troops (VVKO) will likewise disappear as a branch and get rolled into the new VKS.  Russia will be left with three services and two branches (not three of each).

RF and Air Forces Flags (photo:

RF and Air Forces Flags (photo:

The Aerospace Forces will be responsible for all Russian air forces and air defense (and more).

This news comes on the heels of six months of studious MOD denials that such a move was even contemplated.

It began quietly on 1 December  with Defense Minister Sergey Shoygu’s remarks to a regular military leadership videoconference.

According to Krasnaya zvezda, Shoygu discussed changing the organizational structure of the Air Forces in connection with turning VVKO aerospace defense brigades back into air defense (PVO) divisions.  He said the decision was made in mid-2013 after an analysis of mission fulfillment by the Air Forces.  He explained that:

“The goal of the changes being made is to increase the effectiveness of VVS [Air Forces] command and control, to improve the quality of the organization of everyday activity and planning for the combat employment of the troops.”

It echoed an earlier decision to reverse course on Anatoliy Serdyukov’s large composite air bases and groups and put aircraft back into more dispersed divisions and regiments.

By 10 December, Interfaks-AVN reported that the decision to replace the VVS with the VKS awaited only an official announcement.  

The news agency’s MOD source said:

“Formation of the new service [VKS] will proceed gradually, and, as expected, take several years.  In the course of this period, the forces and means entering the VKS must develop in the direction of unification and standardization of command and control, information and strike systems.”

The source also claimed the first CINC of the new service would be a general officer with experience commanding large inter-service [unified or joint] troop groupings, including aviation and PVO.  The most likely candidate — according to the source — Central MD Commander General-Colonel Vladimir Zarudnitskiy.

Then Defense Minister Shoygu made it official on 18 December when he said creating Aerospace Forces would be a priority task for 2015.

TASS reported the VKS CINC will have deputies for aviation, air defense, missile defense (PRO), and space.  It also indicated that VKS will control all current VVS aviation, including frontal and army aviation.  But its sway over the latter two — with the exception of fighter aircraft — will be “purely nominal,” and they will be employed in “coordination” with MD commanders.  Troop PVO will apparently continue to protect army formations.

Military commentator Igor Korotchenko captured the essence of VKS as a reaction to the possibility of a devastating U.S. aerospace attack on Russia:

“The main function [of VKS] is to guarantee realization of the Russian Federation’s concept of aerospace defense, proceeding from the need to counter existing plans, particularly of the United States of America, to implement the prompt global strike concept.  The Americans are planning in the conceivable future to use precision weapons, including hypersonic ones, to destroy [launch] positions and silos of intercontinental ballistic missiles, command centers, communications centers.  The fact here is that this concept will potentially be a great threat for Russia.  These new structures, the new service of the Russian armed forces will be occupied with its deterrence and neutralization.”

Such a potentially disarming threat might mobilize the military and public against America, but Korotchenko and the VKS will have to wait a very long time for it to materialize.  And if it doesn’t appear, then the deterrent worked, right?  A no-lose proposition from Moscow’s perspective.

VKS will be something of an effort to resurrect or reconstruct Soviet PVO Strany — national air defense — that was dismantled beginning in the late 1970s. Serdyukov’s reorganization of the VVS and creation of VVKO are criticized now as focused solely on saving money.  The current thinking is that all aerospace defense systems should be concentrated in a single service and single CINC with authority and responsibility for protecting the country’s aerospace borders.

The new VKS will be anything but compact, as President Putin often calls on the army to be.  They will be a sprawling enterprise that may be challenging to link and inter-connect for operations as a unified command.  If Serdyukov’s changes were too economy-minded, this one errs on the side of Soviet-style giantism. And now isn’t an auspicious time for expensive undertakings.

There are practical issues too.  How will the VKS CINC manage competing requirements for modern fighter aircraft from frontal aviation and air defense?Their number is limited and insufficient for both needs.  So creation of VKS won’t change the fact that they will be spread thinly over a gigantic landmass.

Moral of the story:  Reform, reorganization, and reshuffling never really end no matter the boss — Serdyukov, Shoygu, etc.  VKS may be the answer for a time, but they’re very unlikely to be the last word. 

P.S.  Various reports on VKS provided some indication of deployments in 2015. What is currently the VKO brigade (or will become a PVO division) in Novosibirsk may receive the S-400 this summer.  Shoygu said the MOD will put an air and air defense army (AVVSiPVO or АВВСиПВО) in the Arctic.  More recently, TASS reported an S-400 regiment will be deployed on Novaya Zemlya.

Item 30



HT to for pointing to on the status of work on PAK FA’s advanced “second phase” engine.

Lenta (citing Interfaks) says a source close to ODK General Director Vladislav Masalov says a PAK FA with the “second phase” engine will fly in 2017.

He reportedly said the “second phase” engine will replace “item 117” and give PAK FA supercruise capability while being 15-18 percent more fuel efficient and cheaper to maintain.

Lenta notes the developmental engine is “item 30” not “item 129” as cited previously in Russian media.

The AL-41F1 is “item 117.”  Current PAK FA prototypes and the Su-35S have “item 117S” (AL-41F1S) engines.

Recall, in 2010, ODK along with NPO Saturn hoped the “second phase” engine would fly by 2015.  However, OAK President Pogosyan was considerably less sanguine, saying that the advanced engine might come in 2019, or later.

S-400 Deployments

S-400 Firing (photo: Interfaks-AVN / Andrey Stanavov)

S-400 Firing (photo: Interfaks-AVN / Andrey Stanavov)

Last week Interfaks-AVN wrote that the Russian military just received two “regimental sets” of S-400 / Triumf SAMs.  They make numbers seven and eight.

One became the fourth “regimental set” of the 4th Aerospace Defense Brigade around Moscow and the other is bound for the 1st Aerospace Defense Brigade on the Kola near Northern Fleet headquarters at Severomorsk.

The Kola brigade is the first in the Western MD to have the S-400.  It falls under the Western MD’s 1st Air Forces and Air Defense Command.

The other three of the eight are the 3rd (Kaliningrad), 7th (Novocherkassk), and 12th (Nakhodka) Aerospace Defense Brigades.

Almaz-Antey General Director Yan Novikov told the Interfaks-AVN that, for the first time, the Defense Ministry will get three S-400 “regiments” in a single year in 2014.

TASS reported even earlier last week that Almaz-Antey will deliver the ninth “regiment” will before the end of December.  It will be the first three-battalion regiment, and is destined for Kamchatka, or the 14th Aerospace Defense Brigade (Yelizovo).

In September, the commander of PVO and PRO for VVKO, General-Major Andrey Demin told TASS that 12 “regimental sets” of S-400 and 72 Pantsir-S would be procured by 2020.

Su-35 Deliveries



RBK-TV ran a short segment on 3 October indicating that OAK, Sukhoy, and KnAAZ (aka KnAAPO) will deliver (or will have delivered) 22 Su-35 aircraft to the Air Forces by the end of 2014.

Twelve Su-35 were reportedly delivered in 2013, so 22 plus delivery of 14 more in 2015 would fulfill Sukhoy’s 2009 contract for 48.  There’s been talk all along about a follow-on contract.

The report briefly covered the aircraft’s capabilities and noted that China would be the primary foreign customer for it.  However, according to RBK, the export variant will not carry the same avionics as the domestic version.

The video features OAK President Mikhail Pogosyan saying that the corporation’s military production is fully independent of foreign suppliers (and therefore unaffected by Western sanctions).

The broadcast ends noting that more than 12 billion rubles have been invested in Sukhoy’s modernization over five years.  More than 3 billion from targeted state programs have gone into financing Su-35 development.

PAK FA’s Emergency Landing

Burned PAK FA Bort 055

Burned PAK FA Bort 055

Interfaks-AVN reported yesterday that a PAK FA on a test flight from Zhukovskiy made an emergency landing.

A source told the military news agency that bort number 055 received “insignificant damage” from a fire that was quickly extinguished.  The pilot was unhurt.

There are four flying T-50 or PAK FA prototypes at present, and two used for ground testing.

This wiki article on PAK FA lists the prototypes and when they first flew.  T-50-5 or bort number 055 is the newest, making its initial flight on 27 October 2013.

AVN notes that the prototypes have performed aerial refueling and are working through various supermaneuvers.