NTSB Identification: MIA86MA048.
The docket is stored on NTSB microfiche number 30677.
Scheduled 14 CFR DELTA AIR LINES, INC.
Incident occurred Saturday, December 28, 1985 in FORT LAUDERDALE, FL
Aircraft: BOEING 727-232, registration: N519DA
Injuries: 131 Uninjured.

NTSB investigators traveled in support of this investigation and used data obtained from various sources to prepare this aircraft accident report.

AFTER GEAR RETRACTION DRG TAKEOFF, AT APRX 150' AGL, THE AIRCREW HEARD A LOUD NOISE & NOTED THE #2 ENG HAD FAILED. THEY SECURED THE ENG, DUMPED FUEL & LANDED WITHOUT FURTHER INCIDENT. AN EXAM OF THE #2 ENG REVEALED THE COMBUSTION CHAMBER OUTER CASE, PN 616315, HAD FAILED FROM HI STRESS, LOW-CYCLE FATIGUE. THE FAILURE ORIGINATED AT A 4.6 INCH CRACK AT THE REAR DRAIN BOSS TO CASE WELD. AT THE LAST SHOP INSPN, A SUSPECTED CRACK WAS VISUALLY OBSVD IN THIS AREA. THE CASE WAS PREPARED FOR NON-DESTRUCTIVE TESTING BY GRIT BLASTING IT WITH ALUMINUM OXIDE BEADS TO STRIP OFF NICKEL-CADMIUM PLATING. HOWEVER, THE TESTING DID NOT REVEAL A CRACK. THEREFORE, THE CASE WAS RECOATED WITH NICKEL-CADMIUM & RETURNED TO SVC. AFTER THE FAILURE, AN EXAM OF THE FRACTURE AREA REVEALED THE PRESENCE OF NICKEL & CADMIUM (0.5 TO 0.75 INCH, CENTERED ON THE FRACTURE ORIGIN AREA). THERE WAS EVIDENCE THAT GRIT BLASTING (PRIOR TO NON-DESTRUCTIVE TESTING) HAD MECHANICALLY CLOSED THE PREV CRACK, THUS PREVENTING DETECTION. THE OPERATOR REVISED THE SHOP PROCEDURE TO A SHELL BLASTING METHOD.

The National Transportation Safety Board determines the probable cause(s) of this incident to be:

COMBUSTION ASSEMBLY,OUTER CASING..FATIGUE

The National Transportation Safety Board determines the probable cause(s) of this incident to be:

MAINTENANCE,INSPECTION..IMPROPER..COMPANY MAINTENANCE PERSONNEL

The National Transportation Safety Board determines the probable cause(s) of this incident to be:

INFORMATION INSUFFICIENT..COMPANY MAINTENANCE PERSONNEL

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