Today, there are many active or potential conflicts all over the world. In many cases, the West opposes the East in various ways, most often indirectly. Starting with the war in Ukraine, there is also the war between Israel and Hamas, the impending conflict between Iran and Israel, the Red Sea crisis, the various bloody conflicts in Africa, etc.
There are also potential or frozen conflicts, for example, between China and Taiwan, India versus Pakistan, Turkey versus Greece, as well as the Turkish occupation of Cyprus and Syria, to name a few.
In this context, it would be interesting to shed light on the "aircraft versus anti-aircraft" issue, in the form of the F-35A vs. S-400, which represents the much-vaunted Western spear against the formidable Russian shield, starting today, based on what is known from open sources and plausible estimates.
In this section:
Characteristics of the S-400 Triumf anti-aircraft system
The S-400 Triumf (SA-21 Growler in NATO parlance) is an integrated air defense system, developed by Almaz-Antey. The system entered service in 2007, replacing the S-300P and S-200. According to Rosoboronexport, the S-400 system is capable of destroying all types of aerodynamic targets. in a radius of 380 km and up to an altitude of 30 km, as well as ballistic targets within a radius of 60 km.
According to various open sources, the S-400 system may include the following parts (mainly indicating export versions, represented by the suffix E in the Russian nomenclature):
1. The 55K6E mobile command post.
2. The 91N6E S-band panoramic acquisition and combat management radar.
With a maximum range of 600 km, it would track a target with 4 m² RCS (Radar Cross Section, or Radar Cross Section, which represents the ability of a target to reflect radar signals back to the radar receiver) at 390 km.
According to the radar equation, the detection range is proportional to the 4th root of the target RCS. Thus, it can be calculated that this radar would detect a standard target with an RCS of 1 m² at a distance of more than 280 km (150 nautical miles or NM).
3. The r92N6E X-band multifunctional adar, for target illumination and fire control.
With a maximum range of 400 km, this radar can detect an aircraft with 4 m² RCS up to 250 km, according to its brochure. This translates to 175 km (95 NM) against a standard target of 1 m² RCS.
4. The 96L6E C-band all-altitude acquisition radar, with a maximum range of 300 km.
5. Miscellaneous optional surveillance radars, such as the 76N6 low altitude acquisition radar, as well as the 59N6 Protivnik GE, the 67N6 Gamma DE, the 1L119 Nebo SVU, the Nebo-M or the Resonance-NE low frequency search radars. The Nebo SVU should detect a standard 1 m² RCS target at 215 km.
6. Several types of missiles, as following :
a. 9M96E short range, with a range of 40 km and active radar guidance.
b. 9M96E2 medium range, with a range of 120 km and active radar guidance.
c. 48N6E2/3 long range, with a range of 200/240 km and semi-active radar guidance. It is the main missile of the system.
d. 40N6E very long range, with a range of 380 km and active or semi-active radar guidance.
A typical S-400 battalion consists of a command post, a 91N6E target acquisition radar, and two batteries, each equipped with a 92N6E fire control radar and four TELs (transporter-erector-launchers), with four missiles each. All radars have anti-jamming capabilities.
The S-400 system is designed to cooperate and exchange data with the A-50 airborne early warning and control (AEW&C) aircraft, the older S-300 family of surface-to-air missile systems, as well as the Pantsir S1/2 and Tor-M1/2 short- and medium-range air defense systems, capable of handling threats such as drones and cruise missiles, creating a comprehensive multi-layered defense system.
The Lockheed Martin F-35 Lightning 2 stealth fighter today
On the other hand, the F-35 is a well-known and highly publicized stealth fighter jet. Plagued by various problems, it is still not fully operational, after more than two decades of development. Many of the problems are expected to be solved by the so-called Block 4 upgrade, which is expected to be completed by 2030, according to official American reports.
The planned completion of Block 4 has already been postponed several times, even before the delays concerning the Technology Refresh 3 (TR-3) configuration, which " provides the computing power needed to support the modernized capabilities of Block 4 "The TR-3 has not yet been fully certified, so further delays in the upcoming Block 4 upgrade are to be expected.
In trying to provide a valid answer to the F-35 vs S-400 question, we are considering the F-35A today, in the current Block 3F configuration, not in some eventual configuration, with fantastic capabilities, that may never reach integration.
So, to our knowledge, as of September 2024, the following weapons have not been fully integrated on the F-35, at least on the A version (which is the Conventional Take Off and Landing – CTOL, the most widespread version):
- TheAGM-158 JASSM (Joint Air-to-Surface Standoff Missile), which is carried externally, compromising stealth.
- The GBU-53/B StormBreaker (Small Diameter Bomb – SDB II),
- TheAGM-154JSOW (Joint Standoff Weapon),
- TheAGM-88G AARGM-ER (Advanced Anti-Radiation Guided Missile – Extended Range)
All of these weapons are currently being integrated. Integration efforts could (or will certainly) take several years. Therefore, the only relevant medium-range weapon that could be used today is the GBU-39/B SDB (Small Diameter Bomb). In addition to the SDB, the F-35A can use various smart bombs (JDAM – Joint Direct Attack Munition, LGB – Laser Guided Bomb) or less smart (i.e. iron) bombs.
Regarding the F-35 RCS, We have proposed an approach in two steps to predict the RCS of any target. In a nutshell, a 3D model of the target is first created and refined based on available data, photos and videos, and then the RCS is calculated using computational electromagnetics. Following this approach, it was estimated that the F-35 RCS measures approximately 0,01 m² in X-band and 0,02 m² in S band.
According to independent simulation results, the RCS of the F-35 without RAM (Radar Absorbing Materials) is 0,09 m² in X-band and 0,15 m² in S-band (average RCS of the “clean” F-35 model, Case 2). In trying to emulate the use of RAM, a reasonable attenuation of -10 dB could be considered, which would give RCS values of 0,009 m² in X-band and 0,015 m² in S-band. This latter, more favorable set of values will be used in the following calculations.
F-35A vs S-400: Who has the advantage today?
In light of the above, the F-35 should be detected at 54 km (29 NM) from the X-band 92N6E, i.e. the system's main radar, which could guide a missile to the target. The S-band 91N6E surveillance radar would detect the F-35 at 97 km (52 NM).
This radar could direct an active radar missile towards the target, which could acquire and track the target during the end game. Regarding the Nebo SVU early warning radar, it was calculated that it could detect an F-35 at 152 km (82 NM). However, such a radar cannot provide a military-grade track.
The idea of launching an active radar missile on an imprecise trajectory by the Nebo SVU is rather far-fetched, but not unthinkable. In any case, any detection would trigger the take-off order to the rapid reaction alert aircraft, such as the Su-35 or even Su-57, in order to intercept the target.
So, regarding the F-35, one can imagine three concentric circles around the S-400 system, approximately 80, 50 and 30 NM from the three radars mentioned above: an F-35 would have to be on alert within 80 NM, would face medium danger within 50 NM, while it would be extremely dangerous to fly within 30 NM of an active S-400 system.
So any type of bomb (smooth, laser or JDAM) is out of the question, since it would have to be dropped well inside the 30NM circle of death, leaving only one candidate for attack, the SDB.
An F-35A can carry 8 SDBs and 2 AIM-120 Advanced Medium-Range Air-to-Air Missiles (AMRAAM) for self-defense. In order to paralyze the S-400 system, the F-35 would attempt to drop its 8 SDBs simultaneously to cause saturation, outside the 30 or even 50 NM circle.
The exact SDB delivery envelope is not publicly known, but it can be assumed that the F-35 can deliver its SDBs at sufficient altitude and speed, allowing them to glide for approximately 50 NM. On the other hand, this would place the F-35 in the heart of the S-400's detection and engagement envelope.
However, the most important problem is targeting: the SDB carries a small warhead (206 lb) and is used against stationary targets, whose coordinates are known. The S-400 is a mobile system and its elements can move at any time. In most cases, it is rather difficult to obtain the exact coordinates of the various parts of the S-400 system and launch an attack within a reasonable time.
Such an undertaking would require near real-time satellite imagery, image analysis, targeting, mission planning, and transmission of target coordinates to the aircraft. The SDB is poorly suited to a mobile system, such as the S-400. In any case, the GBU-39/B glide bombs would be detected by the fire control radar and intercepted, most likely by the connected Pantsir S1/2 or Tor-M1/2 systems.
Radar horizon and low-flying targets
A mobile system like the S-400, based on large and heavy trucks, would need a relatively flat area to be deployed. It cannot be installed on a mountain, like a conventional surveillance radar. Due to the curvature of the Earth, a low-flying target could come very close to the radar, hidden under the radar horizon and behind the irregularities of the terrain.
In order to calculate the radar horizon, we can use the following formula:
R=1,23(√hr+√ht),
where R is the range expressed in NM, hr the radar height and ht the target height, both expressed in feet.
Let's look at the case of an S-400 system located at the Khmeimim airbase in Syria. The airport elevation is 157 feet, according to open sources. Assuming there is a low altitude acquisition radar, such as the 76N6, on a 40-foot 6V78M mast, the total height of the radar is 235 feet.
The typical altitude of a cruise missile (like the Tomahawk or SCALP EG) is 50 m or 164 feet. Applying the above formula, we get a range of about 35 NM, well below the maximum detection range possible against the F-35. For a missile cruising at Mach 0,9 or 600 knots, the time available before impact is 210 seconds.
In a nutshell, assuming the location of the S-400 system is known, one could use either the BGM-109 Tomahawk land attack missile, the AGM-158 JASSM launched from an F-16, the SCALP EG launched from a Mirage 2000 or a Rafale, or any other similar cruise missile (or missiles), leaving very limited reaction time for the air defense system.
Additionally, aside from an optical sensor, all of these missiles carry a larger warhead (1000 lb class) compared to the SDB, inflicting significant damage.
Conclusion
Following the above analysis, it appears that at the moment the F-35A cannot seriously threaten a fully operational S-400 system, in conjunction with short-range air defense systems.
This situation could change later, with the integration on the F-35A of more advanced weapons, with longer range and adapted sensors, such as the AARGM-ER, the StormBreaker (SDB II), and notably the JASSM. However, at that time (which could be during the next decade), a more relevant question would be that of the F-35 versus the S-500.
This does not mean that the S-400 is invincible, because He was beaten many times in Ukraine. Its main threats are cruise missiles (which take advantage of the limited radar horizon, as explained), ballistic missiles (which approach at very high speed), quasi-ballistic missiles (with unpredictable trajectories), as well as drone swarms (for saturation attacks), causing a possibly excessive consumption of missiles for their interception.
In any case, the S-400 is a defensive weapon system protecting a specific area. No defensive weapon system has ever won a war. It would simply buy time, by enabling or protecting, for example, an attack or counterattack by other means.
Note: All of the above are personal opinions and assessments of the author and do not necessarily express the views of the Hellenic Air Force or the Hellenic Air Force Academy.
Konstantinos C. Zikidis
Electronics Engineer, Ph.D.
Military teaching staff at the Hellenic Air Force Academy
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As explained in the article, flying at very low altitude (terrain following mode) hides an attacking aircraft from ground radars, allowing the intruder to launch a surprise attack, especially if it is equipped with suitable weapons, such as cruise or anti-radar missiles.
However, flying at very low altitude:
– This significantly increases fuel consumption, thereby decreasing range.
– This limits the situational awareness and the view of sensors (optical or radar).
– This limits the range of weapons, especially gliding bombs.
– This does not solve the problem if the anti-aircraft system is connected to an airborne radar.
So there are also serious disadvantages to low-altitude flying. In terms of cost, the best solution would be the swarm of suicide drones, such as the Iranian/Russian Shahed 136, at around €20 each. So, 000 Shahed 20s cost less than one AGM-136B HARM (High speed Anti-Radiation Missile).
[I must admit that I used Google Translate from English to French.]
Thanks Konstantinos,
much clearer for me even if you did not address in your reply the effectiveness of low altitude attacks (aircrafts in “terrain following” mode).
Have a nice day
So for your information, the comments are also automatically translated. It is therefore preferable to write the comments in French when possible, because the technical solution is that French is translated into all languages, but nothing is translated into French.
Low RCS is always an advantage for a fighter. However, it is not sufficient, if there are no suitable weapons. If the only available weapons are bombs, it would not be a good idea to go against an advanced anti-aircraft system, such as the S-400, because you would have to enter the danger zone in order to deliver the bombs. If you could use a stand off weapon, such as the JASSM (Joint Air-to-Surface Standoff Missile) with a range of 370 km for the -A version, then even a good old F-16 could do the job. In any case, it is not imperative to use an aircraft: an effective approach would be a combination of low-cost suicidal drones, with some cruise missiles and a few ballistic missiles, launched in a way to arrive more or less at the same time . More or less this is what Iran did against Israel on the evening of 13 April 2024.
Analysis that seems interesting but beyond my skills to truly judge.
And I'm not sure I understood the conclusion.
Is the most effective way to challenge an S-400 stealth (whatever the aircraft) or a -very- low altitude approach (terrain following, whatever the aircraft)?
Thank you for your insights and best regards.