The Boeing 757-200 EXCALIBUR—the specially modified aerial demonstrator and flight laboratory developed to advance communications, radar, and sensor suites for the GCAP (Global Combat Air Programme)—recently completed a new flight test campaign. The aircraft appeared equipped with an unprecedented nose radome and new ventral fairings.

Compared to the configuration utilized during the initial 2024 test phase—where the aircraft featured three green fairings on the forward fuselage (two lateral and one ventral)—February 2026 imagery reveals a distinct green nose radome, now markedly pointed in a fighter-style profile. Additionally, a green and white fairing is positioned beneath the nose, alongside a further ventral protrusion located on the rear section of the fuselage (white/grey). Furthermore, new yellow-colored bulges are clearly distinguishable on the pre-existing lower fairing.

Overall, this new configuration brings the EXCALIBUR significantly closer to the renderings previously released by 2Excel Aviation regarding the aircraft's final design. Compared to those renderings, two lateral fairings are still missing, and the rear ventral modification currently appears as a single elongated body rather than the two separate small elements depicted in the concept art—though it cannot be ruled out that the current iteration "envelops" the rendered solution.

It remains unclear whether these new additions represent aerodynamic modifications to test the aircraft's flight envelope or if they already house functional components of the ISANKE (Integrated Sensing And Non-Kinetic Effects) mission suite and/or ICS (Integrated Communications Systems) hardware. Leonardo UK, the prime contractor for the EXCALIBUR, has not issued statements on the matter. However, given that mission equipment installation was scheduled by late February, it is plausible that some communication devices and sensors (radar, RWR, EW systems) under development for the TEMPEST core fighter are already present within the fairings, particularly the older ones dating back to 2024.

Furthermore, it should be noted that alongside the flying EXCALIBUR, a second 757 operates as a digital twin. This airframe was dismantled and reproduced digitally to perform exhaustive ground testing—avoiding the consumption of costly flight hours—with results subsequently verified by the physical aircraft.

In the coming years, this "British" mini-fleet will be joined by two additional "national" testbeds: a GULFSTREAM business jet for Italy and a C-2 transport aircraft for Japan, completing the trilateral experimental infrastructure of the GCAP program.

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