The sensors are all attached via thermocouples to the “brain” of the engine, the brain box then pings the data via satellite to the control centre in England at Derby
The control room at Derby has senior engineer who at anyone time monitor between 8,000 and 10,000 engines 24/7 365
The data appears in graph form and any discrepancys are singled out and investigated
They have direct contact with pilot, airline, airport and RR teams at airport on the ground
The engineers work with the pilot to rectify any anolomys and in worst case provide back engines and spares if need within hours anywhere in the world
The data that is collected can be pulled up from data archive going back 10 years at the derby control centre but requesting historical data requires permission from higher up and takes longer
That way they can see specific trends in data for specific engines and anolomys might be just the way the engine performs
I know this because i know someone who works there and it took 2 years of application to get the job having spent 5 years in the Royal Navy with hands on engine maintenance
Most of the guys are ex-service men who have years of experience from helicopters and warships
Rolls Royce take apprentices at 16 all the way to 65 and then their children start at 16 and so on, there is 3 generations of same family there
There’s a reason why RR is the best it’s the culture within and trust me they are soooo serious about the job