The F-117s have operated from Joint Base Elmendorf-Richardson for NE 23-1 earlier this month. But the most interesting thing is the presence of the removable radar reflectors installed on the stealth jet.
An unspecified number of U.S. Air Force F-117 Nighthawks have taken part in exercise Northern Edge 23-1 at Joint Base Elmendorf-Richardson, Alaska. Six photos posted on the U.S. DoD DVIDS network show the iconic stealth jets arriving at JBER to join the “joint, multinational and multi-domain operations designed to implement high-end, realistic war fighter training, develop and improve joint interoperability, and enhance the combat readiness of participating forces” on May 10, 2023.
While the release of some official photos of the F-117 is always interesting, in this case, the most remarkable thing is that the jets carry something rarely in recent images and videos. The devices, whose shape is a truncated pyramid with a trapezoidal base, are removable radar reflectors or RCS (Radar Cross Section) enhancers.
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.
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.
The lenses are not new to the F-117, obviously. They were carried every now and then in the past, although, most of times, the Nighthawks flew without radar reflectors. They were installed for ferry flights and it is possible they were fitted for the flight from Tonopah Test Range to JBER.
Back to the F-117, we have reported about the latest updates recently. Here’s what we have written last time:
While officially retired in 2008, the F-117 Nighthawk have continued to fly, unofficially, from Tonopah Test Range (TTR) airfield in Nevada. As explained in a detailed story, back in 2014, after a few videos and photographs had already appeared online, the U.S. Air Force admitted that the Nighthawk was kept in a “Type 1000” storage at TTR which meant that the type is had to be maintained until called into active service. Desert conditions of Nevada are perfect for maintaining the stealth jets in pristine conditions (due to the low level of humidity and hence, lower probability of corrosion), hence the reason to operate the enigmatic aircraft from TTR.
In July 2016, we published a video showing two F-117s flying together, filmed from the distant hills east of Tonopah Test Range, then, in 2017, the U.S. Air Force announced the decision to retire the fleet permanently, once and for all. In fact, “in accordance with the National Defense Authorization Act of 2017, passed Dec. 23, 2017 the Air Force said it would remove four F-117s every year to fully divest them. However, the aircraft continued to be spotted, even more than it had happened until then, with the Nighthawks also deploying to several U.S. bases to carry out Dissimilar Air Combat Training with other U.S. types. Until 2021, when the U.S. Air Force published the first official images of the type still involved in flight operations on the DVIDS (Defense Visual Information Distribution Service) network.
Then, in September 2022 the Air Force Test Center published a Request For Information (RFI) about a possible 10-year contract for maintenance and logistics support services for the F-117A fleet at the TTR airfield, acknowledging that the U.S. Air Force is willing to keep the aircraft flying at least until 2034.
Anyway, it’s no longer a secret that 15 years after being officially retired, the F-117s are being actively used not only for training purposes as adversary aircraft and cruise missile surrogate, but also for research, development, test and evaluation.
For what concerns NE 23-1, some 10,000 U.S. service members, five ships and more than 150 aircraft participated in the drills at various locations in and around Alaska. United Kingdom and Australian service members also joined the U.S. contingent in the U.S. Indo-Pacific Command exercise. According to a Pacific Air Forces release, operating locations for the drills included Joint Base Elmendorf-Richardson, Eielson Air Force Base, Fairbanks International Airport, and Ted Stevens International Airport, among others. The training took place in and over the Joint Pacific Alaska Range Complex, Gulf of Alaska, and temporary maritime activities area.
We don’t know the exact role the F-117s played in the exercise but, if they were called in, their somewhat vintage stealth capabilities were needed to make the scenario more challenging for the other players!
About David Cenciotti
David Cenciotti is a journalist based in Rome, Italy. He is the Founder and Editor of “The Aviationist”, one of the world’s most famous and read military aviation blogs. Since 1996, he has written for major worldwide magazines, including Air Forces Monthly, Combat Aircraft, and many others, covering aviation, defense, war, industry, intelligence, crime and cyberwar. He has reported from the U.S., Europe, Australia and Syria, and flown several combat planes with different air forces. He is a former 2nd Lt. of the Italian Air Force, a private pilot and a graduate in Computer Engineering. He has written five books and contributed to many more ones.