QUOTE:
''I'd been under the impression that engine designs early in their lifecycle tended to have these kinds of problems, as even the best testing will never fully replicate real-life conditions.''
The uncontained release of a turbine disc during development testing is an extremely rare occurrence for R-R (Derby) in my experience. Only three instances in 31 years if my memory serves me correctly and one of those wasn't even a civil engine.
R-R, and all other aircraft engine manufacturers go to great lengths to accurately replicate everyday operational conditions during their development testing and go much further than service conditions by running with simultaneous low oil pressure/ high oil temperature, increased cabin bleed off-take (where applicable), increased vibration, increased TGT and speeds, increased wheel case loadings etc. etc. This rigorous testing schedule is required by the authorities well before any new engine type enters service so as to eliminate the sort of incident QANTAS have just experienced. Also, engine manufacturers are required to provide high cyclic data ahead of service hours/cycles to hopefully highlight any possible future mechanical issues that may arise.