Originally Posted by
Cropduster
Question about windmilling engines in general, and the GE-90 in particular.
If you shut an engine down in flight and leave it windmilling for a few hours, is there any risk of damage to the engine?
If you shut it down for oil loss/low oil pressure - definitely yes.
If it still has oil, the windmilling of the engine will drive the oil pump at sufficient speed to provide oil to the bearings, so the risk of damage is minimal.
The AMM has guidance for what actions are required for an extended engine windmill and what minimum windmill oil pressures you need to avoid damage.