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Output Number
R20000026
Approval Date
Published Date Time
Recommendation type
Recommendation
Mode
Aviation
Date released

The Australian Transport Safety Bureau (formerly the Bureau of
Air Safety Investigation) recommends that the engine manufacturer
General Electric review the adequacy of turbine blade manufacturing
process controls to reduce the likelihood of blades containing
casting defects being released into service.





As a result of investigation into this occurrence, the Bureau
simultaneously issues the following recommendation and safety
advisory notice:





R20000025



The Australian Transport Safety Bureau (formerly the Bureau of Air
Safety Investigation) recommends that the engine manufacturer
General Electric identify the source of the casting defect of the
failed HPT blade.





SAN20000027



The Federal Aviation Administration should note the safety
deficiency identified in this document and take appropriate
action.

Organisation Response
Date Received
Organisation
General Electric Usa
Response Text

An audit was conducted of actions or precautions currently being
taken to preclude the existence of dross and similar impurities in
final castings at the two casting sources utilized for manufacture
of the Stage 2 CF6-80A HPT Blade. All procedures were found to
conform to GE and internal casting source specifications. Extensive
procedures are in place at each source to minimize the likelihood
of blades containing casting defects being released into
service.



The frequency of problems related to casting anomalies is extremely
low. Out of a total of 69,963 Stage 2 CF6-80A HPT blades produced
by both casting sources, casting related operational problems have
been reported on 4 blades (0.006%).