Midway Airport
Aircraft Accident/Incident Report

Chicago, Illinois 60638
Saturday, October 4, 1997 8:10 CDT

NTSB Narrative Summary Released at Completion of Accident

The left main landing gear outboard wheel/brake assembly separated from the airplane during a landing roll. The Captain did not report any difficulties in controlling the airplane. Inspection of the failed axle revealed a crack which originated at the surface of one of the brake flange holes. This crack had previously been repaired. Detailed metallurgical examination of the crack revealed properties consistent with the surface having been heated to an excessive temperature during the repair process.

NTSB Probable Cause Narrative

an improper repair to a crack in a brake flange hole on the left main landing gear outboard axle, and subsequent fatigue failure of the axle.

Event Information

Type of Event Incident
Event Date 10/4/1997
Event Day of the Week Saturday
Time of Event 810
Event Time Zone Central Daylight Time
Event City CHICAGO
Event State ILLINOIS
Event Country --
Zipcode of the event site 60638
Event Date Year 1997
Event Date Month 10
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport MIDWAY
Event Location Nearest Airport ID MDW
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation 620
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 753 Central Daylight Time
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID MDW
Elevation of weather observation facility 620
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation CDT
Lighting Conditions Day
Lowest Ceiling Height 8500
Lowest Non-Ceiling Height 6000
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling Overcast
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 6
Air Temperature at event time (in degrees celsius) 21
Dew Point at event time (in degress fahrenheit) 18
Wind Direction (degrees magnetic) 240
Variable Wind Indicator Unknown
Wind Speed (knots) 10
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) --
Intensity of Precipitation Light
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 50
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 5038
NTSB Notification Source --
NTSB Notification Date Oct 4 1997 12:00AM
NTSB Notification Time 840
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 12:36PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N129SW
NTSB Number CHI98IA007
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 121: Air Carrier
Type of Flight Plan filed IFR
Flight plan Was Activated? --
Damage Minor
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Boeing
Aircraft Model 737-200
Aircraft Series Identifier 737-200
Aircraft Serial Number 22340
Certified Max Gross Weight 115500
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 130
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection Aug 20 1997 12:00AM
Airframe hours since last inspection 386
Airframe Hours 49400
ELT Installed Unknown
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name FIRST SECURITY BANK
Aircraft Owner Street Address 79 SOUTH MAIN ST.
Aircraft Owner City SALT LAKE CITY
Aircraft Owner State UT
Aircraft Owner Country
Aircraft Owner Zipcode 84111
Operator is an individual? --
Operator Name SOUTHWEST AIRLINES
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address 2702 LOVE FIELD DRIVE
Operator City DALLAS
Operator State TX
Operator Country
Operator Zip code 75235
Operator Code SWAA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Passenger Only
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code MCI
Departure City KANSAS CITY
Departure State MO
Departure Country
Departure Time 710
Departure Time Zone CDT
Destination Same as Local Flt crash at destination city
Destination Airport Code MDW
Destination City
Destination State
Destination Country
Specific Phase of Flight Landing
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Dec 20 2002 12:42PM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 31C
Runway Length 6522
Runway Width 150
Sight Seeing flight No
Air Medical Flight No
Medical Flight --