Serious incident Boeing 737-76Q N551WN,
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ASN Wikibase Occurrence # 370201
 
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Date:Wednesday 1 October 2008
Time:10:55 LT
Type:Silhouette image of generic B737 model; specific model in this crash may look slightly different    
Boeing 737-76Q
Owner/operator:Southwest Airlines
Registration: N551WN
MSN: 30280/1025
Total airframe hrs:21206 hours
Engine model:CFM CFM56-7B22
Fatalities:Fatalities: 0 / Occupants: 133
Aircraft damage: Minor
Category:Serious incident
Location:Chicago-O'Hare International Airport, IL (ORD/KORD) -   United States of America
Phase: Taxi
Nature:Passenger - Scheduled
Departure airport:Kansas City International Airport, MO (MCI/KMCI)
Destination airport:Chicago-Midway Airport, IL (MDW/KMDW)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The airplane experienced separation of the right nose landing gear (NLG)wheel assembly as it exited runway after landing. Metallurgical examination revealed that the NLG axle fractured in a transverse plane, and that the failure of the axle was due to intergranular cracking that acted as stress concentrators from which fatigue cracks emanated. The fracture of the right side inboard journal on the NLG inner cylinder assembly was most likely due to the failure of a prior tapered roller bearing. Eventually the size of the fatigue crack and the forces generated during landing were sufficient to drive the crack in overstress, leading to fracture of the inboard journal. The change in ownership of the plane and the monthly swapping of bearings and wheels make it difficult to determine when the bearing failure occurred or why.

Probable Cause: The right nose landing gear axle's failure from intergranular and fatigue cracking due to an earlier bearing failure.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: ENG08IA042
Status: Investigation completed
Duration: 1 year and 5 months
Download report: Final report

Sources:

NTSB ENG08IA042

History of this aircraft

Other occurrences involving this aircraft
22 February 2008 N551WN Southwest Airlines 0 Valdosta, GA non
18 March 2023 N551WN Southwest Airlines 0 Hollywood Burbank Airport, CA (BUR/KBUR) non
Runway incursion

Location

Revision history:

Date/timeContributorUpdates
25-Mar-2024 08:10 ASN Update Bot Added

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