Incident · 2011-10-23
What the record says
- Event date
- 2011-10-23
- Event type
- Incident
- Highest injury level
- No injuries
- Aircraft
- BOEING 747-451 (N661US)
- Operating rule
- Part 121
- Operator
- DELTA AIR LINES, INC. Operator named in NTSB report
- Operated by (per NTSB report)
- DELTA AIR LINES INC
Probable cause
The penetration of turbine blade fragments through the rear turbine case, which punctured the No. 4 bearing oil pressure supply tube, allowing misted oil to contact the hot engine case and ignite the undercowl fire. Contributing to the incident was the installation of approved (but not preferred) stage 3 low pressure turbine outer transition duct segments with the riveted rear seal configuration and the failure of the engine design to comply with the engine debris containment requirements of 14 Code of Federal Regulations 33.13 and 33.75.
Source: NTSB case ENG12IA003Flight crew
No flight-crew details recorded in the NTSB accident database for this event.
Facts as the NTSB records them — GroundCheck adds no judgement. Preliminary records may be revised as the investigation proceeds.