To develop the sixth-generation fighter Tempest under the Global Combat Air Programme (GCAP), led by the United Kingdom, Italy, and Japan, a specialized aircraft named Excalibur had to be created. Essentially, this refers to a "flying laboratory" based on a passenger Boeing 757, which initially received special pods and will undergo further modifications in the future.
It is within these pods that a complex known as ISANKE & ICS (Integrated Sensing and Non-Kinetic Effects & Integrated Communications Systems) will be installed, encompassing a system for electronic warfare and reconnaissance, as well as communication systems.
Currently, Excalibur has completed the first phase of modifications and flight testing, as reported by the British segment of the Italian conglomerate Leonardo, which is collaborating with the British company 2Excel on this project. The cost of creating Excalibur, according to the 2023 contract, is approximately $150 million.
This is merely the first stage of the aircraft's "mutation," as additional systems for the future Tempest will be installed and tested in flight. For instance, the aircraft's nose will be replaced with the one intended for the fighter, which will also house an electro-optical station in the front section. Two additional "protrusions" will appear on the left side, along with two sensors positioned under the fuselage closer to the tail.
Moreover, the aircraft will feature a "virtual cockpit" for the fighter, in addition to workstations for technicians and engineers. Given that the Boeing 757 can remain airborne for about 8 hours, this will provide ample time to work with the systems of the future sixth-generation fighter.
It’s worth noting that Tempest aims to surpass FCAS (France, Germany, Spain) in the race to develop a sixth-generation fighter. The first flight of Tempest is scheduled for 2028, with the first units expected to enter service in 2035. Meanwhile, FCAS is currently lagging, prompting French company Safran to fear a loss of expertise in engine development.