Quote: Reminds one, somewhat, of UA232.
The UA 232 fan disk failure occurred with about 5 hrs. of usable life left before mandatory removal and disposal. The disk was ~ 20 years in service. The defect that caused the ultimate failure was detectable but missed during its last UA shop inspection. The defect was present in other fan disks that were sliced from the same billet. Thirty or more years ago there wasn't the sophistication in inspection methods and this was a critical rotating part, highly inspected with the best techniques of the day.
The tube is not really viewed as a critical component and as such doesn't receive as much attention.
The 1000 test stand failure was probably the result of a different cause than the 900 failure, but certainly demonstrated what can happen when oil accumulates in the wrong area of a hot turbine.