Engines in Southwest Flight 1380 Accident Under the Spotlight

The CFM engines that power the Boeing 737-700 are in the spotlight, and not for reasons that anyone is happy about.

The NTSB said that it is aware that there might be a connection with another uncontained engine failure over the Gulf of Mexico with another 737-700 with the same engine model in 2016. The damage the departing engine parts inflicted on the fuselages in the two accidents is strikingly similar. The chief suspect is a cracked fan blade. The NTSB cautioned that it is aware of the similarities between the accidents; but it was trying to determine what went wrong on 1380 first.

In an uncontained engine failure, the engine fails catastrophically and parts break off while spinning at around 5,000 rpm. The "uncontained" part of the expression refers to the parts breaking through the engine. In the case of Engine One on Flight 1380, photographs of the failed engine suggest that a single fan blade broke off, ripping through the forward cowling and leaving a path of destruction in its wake.

The NTSB has not yet announced its preliminary findings, but some are calling for the FAA to issue immediate inspections for the CFM 56 engine model. There are more than 1,100 Boeing 737-700s in the fleet and more than 30,000 CFM56 engines in the fleet in a variety of Airbus and Boeing models.