Incident · 2010-12-24
What the record says
- Event date
- 2010-12-24
- Event type
- Incident
- Highest injury level
- No injuries
- Aircraft
- BOEING 737 (N248WN)
- Operating rule
- Part 121
- Operator
- SOUTHWEST AIRLINES, CO. Operator named in NTSB report
- Operated by (per NTSB report)
- Southwest Airlines
Probable cause
The probable cause of the undercowl in-flight engine fire was the insufficient installation torque of the bolts that secure the fuel manifold cover to the fuel manifold. Engine vibrations and fuel pressure cycles caused the bolts to gradually loosen further until one bolt lost all its tightening torque and fell out. The internal fuel pressure then forced open the fuel manifold cover at the location of the missing bolt, causing a gap between the two mating surfaces which allowed fuel to push past the integral packing, resulting in a fuel leak onto the hot engine cases where it ignited resulting in a fire.
Source: NTSB case ENG11IA011Flight crew
No flight-crew details recorded in the NTSB accident database for this event.
Facts as the NTSB records them — GroundCheck adds no judgement. Preliminary records may be revised as the investigation proceeds.