Some of 5th gen. aircraft have operated in “full stealth mode” to train in the most realistic scenarios.
As we already reported, F-35s from Italy, United States and the Netherlands are training together at Amendola Air Base, in southern Italy, during the exercise “Falcon Strike 2022”, which runs from November 15 to 28, 2022. The exercise is focused on the integration between fifth and fourth-generation aircraft and between different F-35 operators.
In our previous story, we mentioned that the F-35 is part of both the Blue Air and Red Air, in simulated scenarios that might see NATO involved in combat operations against adversaries flying other 5th generation aircraft. This possibility seems increasingly plausible as the world is in a new era of great-power competition where the main players (US, NATO, China and Russia) have 5th generation aircraft in service.
Large-scale exercises like the renowned Red Flag are also integrating F-35s as adversary aircraft, as happened last summer with the participation of F-35s assigned to the 65th Aggressor Squadron during the 22-3 edition. The objective is in fact to prepare the participants for the high-end fight, combining great power competition-level threat complexities with the joint interoperability necessary to succeed in future combat scenarios.
It must then not come as a surprise, although it’s a first for the exercise, that some of the F-35s taking part in Falcon Strike 2022 are also flying without the usual RCS (Radar Cross Section) enhancers/radar reflectors normally installed during peacetime and training operations. The aircraft are flying this way with their lowest radar “signature”, taking full advantage of their low-observable capabilities.
Here’s what radar reflectors are, as explained in a previous article posted here at The Aviationist in 2018:
Stealth aircraft, such as the F-22 Raptor or the F-35 Lightning II 5th generation jets are equipped with Luneburg (or Luneberg) lenses: radar reflectors used to make the LO (Low Observable) aircraft (consciously) visible to radars. These devices are installed on the aircraft on the ground are used whenever the aircraft don’t need to evade the radars: during ferry flights when the aircraft use also the transponder in a cooperative way with the ATC (Air Traffic Control) agencies; during training or operative missions that do not require stealthiness; or, more importantly, when the aircraft operate close to the enemy whose ground or flying radars, intelligence gathering sensors.
This is what we explained explaining how the Israeli the heavy presence of Russian radars and ELINT platforms in Syria cause some concern to the Israeli F-35 Adir recently declared IOC:
[…] the Russians are currently able to identify takeoffs from Israeli bases in real-time and might use collected data to “characterize” the F-35’s signature at specific wavelengths as reportedly done with the U.S. F-22s.
In fact, tactical fighter-sized stealth aircraft are built to defeat radar operating at specific frequencies; usually high-frequency bands as C, X, Ku and S band where the radar accuracy is higher (in fact, the higher the frequency, the better is the accuracy of the radar system).
However, once the frequency wavelength exceeds a certain threshold and causes a resonant effect, LO aircraft become increasingly detectable. For instance, ATC radars, that operate at lower-frequency bands are theoretically able to detect a tactical fighter-sized stealth plane whose shape features parts that can cause resonance. Radars that operate at bands below 300 MHz (lower UHF, VHF and HF radars), such as the so-called Over The Horizon (OTH) radars, are believed to be particularly dangerous for stealth planes: although they are not much accurate (because lower frequency implies very large antenna and lower angle accuracy and angle resolution) they can spot stealth planes and be used to guide fighters equipped with IRST towards the direction the LO planes might be.
F-35s deployed abroad usually feature their typical four radar reflectors: to exaggerate their real RCS (Radar Cross Section) and negate the enemy the ability to collect any detail about their LO “signature”. As happened during the short mission to Estonia and then Bulgaria, carried out by the USAF F-35As involved in the type’s first overseas training deployment to Europe or when, on Aug. 30, 2017, four U.S. Marine Corps F-35B Lightning II joined two USAF B-1B Lancers for the JSF’s first show of force against North Korea: the F-35Bs flew with the radar reflectors, a sign they didn’t want their actual radar signature to be exposed to any intelligence gathering sensor in the area
Since they almost always fly with the radar reflectors, photographs of the aircraft without the four notches (two on the upper side and two on the lower side of the fuselage) are particularly interesting: for instance, some shots taken on Jan. 24, 2018 and just released by the U.S. Air Force show F-35As deployed to Kadena AB, Japan, in October as a part of the U.S. Pacific Command’s Theater Security Package program, preparing to launch without their Luneberg reflectors.
As a matter of fact, so far, some RNLAF F-35As and some of the USAF F-35As (with the latter ones, already returned to RAF Lakenheath after the first week) have flown without RCS enhancers, whereas we haven’t (ever) seen any Italian F-35A or B flying without the radar reflectors.
Considering that F-35s have started to operate without radar reflectors during real operations, it seems quite likely that we will see Lighting II aircraft operate in “full stealth mode” more frequently during exercises across Europe in the near future.