Southwest Airlines

Engine blade on Southwest jet showed signs of cracking

An engine fan blade that showed signs of metal fatigue broke off, causing the emergency landing of a Southwest Airlines jet last month, investigators say.

The plane landed safely in Florida after shrapnel from the broken engine hit the fuselage, leaving a 5-inch by 16-inch hole in the outer layer of aluminum above the left wing and causing the plane to lose cabin pressure.

The National Transportation Safety Board released the details in an update Monday to its investigation of the Aug. 27 incident.

In an emailed statement, a spokeswoman for Dallas-based Southwest said the airline was "continuing to work closely with the NTSB on the investigation of this unique...