Boeing 737 incident near Chicago, Illinois, October 1, 2008
On October 1, 2008 at about 4:55 pm local time, a Boeing 737, registered N551WN, suffered minor damage in an incident during taxi (from runway) near Chicago, Illinois (Chicago Midway airport). It was flown under scheduled airline rules (Part 121). No one was hurt; 133 people were on board or involved.
The NTSB's probable cause their words, unchanged
The right nose landing gear axle's failure from intergranular and fatigue cracking due to an earlier bearing failure.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 1, 2008 · about 4:55 pm local time
- Place
- Chicago, Illinois · Chicago Midway · map
- Type
- Incident
- Injuries
- No one was hurt; 133 people were on board or involved.
- Weather
- not recorded
- Aircraft
- Boeing 737 -76Q · all 737s on the register
- Registration
- N551WN · no longer on the register · serial 30280
- Damage
- Minor damage
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Aircraft structural failure during taxi (from runway)
- Landing gear collapse during taxi (from runway) defining event
The NTSB's findings
- cause Aircraft › Aircraft systems › Landing gear system › Nose/tail landing gear › Failure
- cause Aircraft › Aircraft systems › Landing gear system › Nose/tail landing gear › Fatigue/wear/corrosion
The aircraft
- Airframe total time: 21,206 hours
- Last inspection: continuous airworthiness programme; 3 hours since
- Maximum gross weight: 154,000 lb
- Seats: 145
- Landing gear: retractable
- Engine: Cfm CFM56-7B22 (turbofan); 0 hours total
- Operator: Southwest Airlines, Co.
The flight
- Departed from: MCI Kansas City MO at 2:43 pm
- Destination: MDW Chicago IL
- Flight plan: IFR
- Runway 31C, 6,522 ft by 150 ft
- A second pilot was aboard
Weather at the time
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Cabi | 3 | |||
| Flight crew | 2 | |||
| Passengers | 128 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N551WN the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.