NONE · Boeing 767-223(ER) · 2006-06-02 · Los Angeles, CA, USA
Event
NTSB number
ENG06IA018
Event ID
20060809X01126
Type
Incident
Date
2006-06-02
Location
Los Angeles, CA, USA
Coordinates
33.970813, -118.239608
Injuries
Highest injury
NONE
Fatal
0
Serious
0
Minor
0
Uninjured
3
Total aboard
3
Aircraft
Make
Boeing
Model
767-223(ER)
Registration
N330AA
FAR Part
UNK
Engines
2
Damage
SUBS
Conditions
Light
—
Weather
—
Probable cause
The HPT stage 1 disk failed from an intergranular fatigue crack because of GE's inadequate design of the CF6-80 series HPT stage 1 disk. The inadequate design of the disk resulted in a high stress area in the blade slot bottom aft corner that was at or nearly at the material's capability so that there was no damage tolerance such that a small dent could cause a crack to initiate and propagate to failure. Contributing to the disk's failure was the FAA's failure to mandate an accelerated inspection schedule after a previous CF6-80A uncontained HPT stage 1 disk failure had occurred and after other CF6-80A HPT disks had been found during routine overhaul to have cracks in the blade slot bottom aft corners.