Probable cause
The failure of the right main landing gear inboard axle due to fatigue cracking as a result of fretting damage in one of the brake mounting bolt holes.
NTSB analysis
During landing, the inboard axle of the right main landing gear separated from the airplane. The crew taxied the airplane off the runway and the passengers and crew deplaned with no injuries. Examination of the axle revealed an area of fatigue cracking emanating from the brake mounting bolt hole at the 12:00 position. The fatigue crack likely initiated in an area where there was scoring and fretting damage to the Sermetal coating. In-service examination of brake mounting bolt torque indicated that over time, the brake mounting bolts may loosen allowing the bolts to spin in the holes.
Text from the NTSB. Open the NTSB docket for ENG09IA014 for the full record.
Event
- Date
- Sep 8, 2009
- Type
- Incident
- Place
- Los Angeles, California
- Nearest airport
- Los Angeles International (KLAX)
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Boeing 737
- N-number
- N670SW
- Category
- Airplane
- Damage
- Minor
- Operating rule
- Part 121 (airline)
From the NTSB aviation accident database: N-registered aircraft, events since 2008, data through Oct 28, 2026. The file is published monthly, so the latest weeks are incomplete and recent records can change. The official source is the NTSB aviation investigation search. CheckAero is independent and not affiliated with the NTSB.