A380 engine piece found in Groenland after 9 months

[Turbine D]

Originally Posted by lomapaseo

Yea, should be fun taking all those blades out at 30-40 lbs per piece, on wing

and why should the defect be at one area on the disk rather than just anywhere ? unless of course it's a machining process defect?

Because the defect is contained in the billet. the billet is sliced into what will be multiple disks after forging. The forging process then moves the defect into a particular location of the forged disk. It is not a haphazard event. Fact is, if you were to locate the defect in the billet slice, a computer program can predict after forging where the defect will wind up. Something new in technology comes along everyday, eh?

[sooty655]

Originally Posted by Turbine D

Because the defect is contained in the billet. the billet is sliced into what will be multiple disks after forging. The forging process then moves the defect into a particular location of the forged disk. It is not a haphazard event. Fact is, if you were to locate the defect in the billet slice, a computer program can predict after forging where the defect will wind up. Something new in technology comes along everyday, eh?

But the defect wasn't detected in the billet, or at any subsequent manufacturing stage, so a theoretical ability to track it through the process doesn't help. Similar defects might be in similar places in other discs from the same billet, but defects in other discs could be anywhere unless/until the prime defect cause in the billet is known.

[lomapaseo]

Are they now concluding a material defect was present at the origin of the fracture or is the initiating cause still a mystery?.

[MurphyWasRight]

Originally Posted by sooty655

But the defect wasn't detected in the billet, or at any subsequent manufacturing stage, so a theoretical ability to track it through the process doesn't help. Similar defects might be in similar places in other discs from the same billet, but defects in other discs could be anywhere unless/until the prime defect cause in the billet is known.

If the defect was suspected to be linked to a specific billet seems that only a relatively few discs would need to be inspected. Not clear from the items posted here if that is the case.

The inspections will probably be more general and will be looking for defects that either escaped original inspections (or more likely) grown over time so they now can be detected if present.

Either way would be surprised if inspections did not include the entire disc unless some design feature was identified that stressed one position more that others.
I don't have specific knowledge but would seem the discs would have be very symmetrical and balanced parts.