Rolls-Royce makes aircraft engines as well as beautiful cars. They do well, but even the best engine will eventually suffer from wear and then an inspection needs to be done to see what is possibly wrong. The problem with jet engines is that they are rather expensive to dismantle and then reassemble for inspection. That is why Rolls-Royce developed SWARM in collaboration with the University of Nottingham and Harvard at least in theory.
These are very small robots that can be guided through a hose in a jet engine and then can report what they see through minute cameras. Of course, engines of such complexity are already filled with all sorts of ways to collect data, but the visual update that such a SWARM robot can give would be very convenient and above all easier. The idea is that the mini-robots can even see what happens in a running engine!
Now it is unfortunately not yet a reality for Rolls-Royce, but in the basis the robots have already been developed. All that has to be done is to make the robots slightly smaller. As soon as the limit of 10 millimeters is reached they are ready to actually be able to look in engines. The IntelligentEngine program from Rolls-Royce is now looking into what they can do to make these robots a reality, because the cost savings you get when you do not have to get jet engines from aircraft for maintenance is enormous.
Rolls-Royce does not want to say when they think they have the robots ready for use, but hopefully they will be ready within a few years. Nanobots are still not a reality, but this is a companion that should also be feasible with current technology.