Originally Posted by
aeromech3
I seem to recall that the R.R. Spey had a cable & lever system that would close the HP fuel valve should the LP shaft move rearwards; the old designers had thought it possible!!
For some reason Rolls hasn't used the 'clashing blades' to slow the turbine in the event of a shaft separation. I always figured it had something to do with the 3 spool architecture on the RB211 and Trent, but that wouldn't explain the Spey...
The Trent series uses an electronic Turbine OverSpeed protection system on both the LP and IP shafts that instantly shuts off fuel if a shaft separation is sensed.