Originally Posted by
212man
It does seem to have some of the hall marks of a churning event, although there seem to be some missing elements. If the hot oil was causing the INPUT/ACC 2 cautions then there would also have been the MGB HOT caution too. Also, if it was caused by blocked scavenging there would have been an MGB PUMP FAIL caution, I think. This is generated by the drop in pressure in the scavenge line from the input module to the pump in the MGB sump. This modification came in after the first two churning events, along with splitting the sensor cautions from INPUT# CHIP/ACC#CHIP to INPUT#HOT/ACC#HOT as well - same sensor read both indications but only showed CHIP. They also introduced the procedure to bring the engine to IDLE to reduce the energy being put into the oil by the shearing action of the (submerged) gears.
I do find the temperature rise quite low and gentle for a churning event - particularly as the cooler was now in bypass. This must be the result of selecting IDLE and, if it was indeed churning, it's good to see how effective this action is in practice. Hard to imagine oil seals breaking down at 214 C though.
I had the first 'churning event' on the type so have a bit of insight......
Regarding the temperature, it is likely that 214 C was the lowest (the oil is supposed to cool the MGB). There is also an unconfirmed rumor about smoking hot MGB after landing, and that the fire crew measured an external temperature of close to 300 C.