The Southwest Airlines engine that failed last month allowed debris to puncture the Boeing 737-700’s engine casing and fuselage, according to federal investigators.
A 5-inch by 16-inch hole was found in the left fuselage just above the wing of Flight 3472, according to an update on Monday from the National Transportation Safety Board (NTSB). The passenger cabin wasn’t penetrated, but it depressurized while landing, added a spokesperson for NTSB.
One of the engine’s fan blades separated from its hub during the flight. The surface of the fractured fan blade showed curving crack lines consistent with fatigue. No surprises were found with the surface or the material in the fan blade, which was manufactured from a titanium alloy and coated with a copper-nickel-indium allow, during scanning with electron microscopy and X-ray spectroscopy.
The investigator in charge of the case is Tim LeBaron, who is leading a team of experts in airworthiness, power plants and metallurgy. The investigation will include a non-destructive examination of the blade surfaces for cracks and a review of engine maintenance records.