a cartridge of material to fill in any damaged areas. The robots can also carry small grinding tools, to smooth down ragged surfaces.

Such repairs may not be as permanent as those during a full rebuild, but they are good enough to extend the time an engine can operate between major overhauls. Moreover, data collected by the robots would be used by GE to update the engine’s “digital twin”. These twins are virtual replicas, held on a computer, and contain the latest operating data sent via satellites from sensors mounted inside engines. The twins serve as test beds for spotting problems before they get serious. This means preventive maintenance can be carried out and unscheduled visits to the workshop avoided.

Robots will allow much finer monitoring of an engine’s wear and tear. That varies, according to how aircraft are used—even by particular pilots, some of whom push aircraft engines harder than others do—and where in the world a plane most often operates. Airborne particles, particularly in polluted regions, can block the tiny cooling channels that help stop an engine melting. Wind-blown sand grains in places such as the Middle East subject blades to increased abrasion. Jet engines are already remarkably reliable, with the need for an in-flight shutdown now in the order of once in 20,000 hours of operation, which means a pilot may never experience a failure in his entire career. Tiny robots will make them more so.