"Soak Back"
 

Yes Turbine D, thanks for your reply. I believe that the design of this engine has reduced the mass and increased the energy transfer to such an extent that there is not enough mass in the parts to effectively absorb the waste heat.

Of course this why Qantas chose the T970 engine to achieve greater payloads. As it happened the failure occured when the a/c was not heavily laden and under a reduced TO power setting.

And to quote Rolls Royce verbatim "High in power, yet low in mass." Of course the way to prevent this is to provide auxillary oil pumping after the engine has been shut down to keep the oil flowing and prevent the coking.

But of course if the surfaces are so hot to instantly carbonise the oil under normal use, say in 95% load in TO, there is little to stop this happening. Reading back through the thread an earlier poster stated that 270C was the flash point and not the 210C noted later.