Serious incident Boeing 747-87UF N859GT, Thursday 18 January 2024
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Date:Thursday 18 January 2024
Time:23:34 LT
Type:Silhouette image of generic B748 model; specific model in this crash may look slightly different    
Boeing 747-87UF
Owner/operator:Atlas Air
Registration: N859GT
MSN: 62441/1526
Year of manufacture:2015
Total airframe hrs:36468 hours
Engine model:GE GEnx-2B67/P
Fatalities:Fatalities: 0 / Occupants: 5
Other fatalities:0
Aircraft damage: Minor
Category:Serious incident
Location:near Miami International Airport (MIA/KMIA), Miami, FL -   United States of America
Phase: En route
Nature:Unknown
Departure airport:Miami, FL
Destination airport:Carolina, PR
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
During the airplane's initial climb after departure, the flight crew received engine overheat and fire warning indications for the No. 2 engine. The engine was subsequently shut down, one fire bottle was discharged, and the engine fire light extinguished. After declaring a mayday, the flight returned to the airport and made an uneventful landing.
A review of the airplane's maintenance records revealed that, 4 days before the flight, the airplane had undergone a borescope inspection of the No. 2 engine performed by a third-party vendor. The inspection required the removal of the port M borescope plug. The maintenance work card provided instructions for properly reinstalling the borescope plug to ensure that the locking feature was properly engaged. By initialing the work card, the technician who performed the work and the inspector who reviewed the work indicated that this task had been completed in accordance with the maintenance manual procedure.
A postincident inspection of the No. 2 engine revealed that the engine cases were intact with no evidence of an uncontained engine failure. The inspection also revealed burn through of the thrust reverser fan duct fixed inner wall located directly over the combustor diffuser nozzle (CDN) port M borescope plug. The CDN case port M borescope plug was not secured in the engine case and was found loose in the engine cowling. The open CDN port allowed hot gases to escape from the engine, which caused thermal damage to the thrust reverser.
A postincident inspection of the port M borescope plug revealed no anomalies to the plug's material composition, dimensions, threads or locking components. The plug was threaded into an exemplar engine without binding or stiffness and locked as designed. Although the work card had been initialed by a technician and an inspector, it is likely that the port M borescope plug was not properly secured and inspected according to maintenance manual procedures and that the improperly secured plug resulted in the engine fire.

Probable Cause: Maintenance personnel's improper installation and inspection of the port M borescope plug, which resulted in an engine fire.

Accident investigation:
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Investigating agency: NTSB
Report number: DCA24LA079
Status: Investigation completed
Duration: 9 months
Download report: Final report

Sources:

NTSB DCA24LA079

Location

Media:

Revision history:

Date/timeContributorUpdates
19-Jan-2024 07:46 harro Added
19-Jan-2024 07:47 harro Updated [Other fatalities, Embed code, Narrative, ]
19-Jan-2024 07:48 harro Updated [Other fatalities, ]
19-Jan-2024 08:18 harro Updated [Total occupants, Other fatalities, Source, Narrative, ]
19-Jan-2024 08:27 harro Updated [Other fatalities, Narrative, ]
19-Jan-2024 12:57 harro Updated [Other fatalities, Location, Narrative, ]
19-Jan-2024 15:56 harro Updated [Other fatalities, Narrative, ]
08-Feb-2024 20:07 Captain Adam Updated [Time, Location, Damage, Narrative, Category, Accident report, ]
27-Oct-2024 20:44 ASN Update Bot Updated [Time, Operator, Other fatalities, Phase, Nature, Departure airport, Destination airport, Source, Narrative, ]
27-Oct-2024 20:49 ASN Updated [Other fatalities, Narrative, ]

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