Pilot Debrief

BOEING 747 near Miami, FL — 2010-05-17

Final reportDCA10CA061
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Date
2010-05-17
Location
Miami, FL, USA
Airport
MIA
Aircraft
BOEING 747
Registration
N498MC
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Approach

Probable cause

impact of the fore flap with the aft fuselage after fatigue failure of the right wing fore flap carriage assembly attachment fitting at position 6.

NTSB narrative

On May 17, 2010, an Atlas Air Cargo Boeing 747-400F, N498MC, lost a section of the left fore-flap while on approach to Miami International Airport (KMIA), Miami, Florida. The airplane was substantially damaged when the flap portion impacted the fuselage. There were no injuries to the flight crew and the airplane landed without further incident. The cargo flight originated from Rio de Janeiro-Galeão-Antonio Carlos Jobim International Airport (BGL), Rio de Janeiro, Brazil. According to the operator, the flight crew heard and felt a large impact after 30 degree flaps was selected during the approach. Postflight inspection revealed that approximately twelve feet of the right wing inboard fore flap was missing and had caused substantial damage to the aft fuselage. The separated section of the fore flap was recovered and examined. The examination revealed that a large portion of the enamel was missing from the fore flap attachment fitting of the carriage assembly and that there was a large amount of contamination and grease buildup around the lubrication fitting. Extensive corrosion byproducts covered up the lubrication passage in the attachment, which prevented passage of grease to the bearing, causing extensive corrosion in the bore and propagated by fatigue before final ductile separation.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Inspection and maintenance of the flap attachment fitting prior to flight.

NTSB coding

Evidence available

  • 4 docket documents
View NTSB final reportView NTSB docket

Docket documents4

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