Spirit Airlines Flight 3044

Based on the bird remains and feathers collected and identified by Smithsonian Institution National Museum of Nature History Division of Birds - Feather Identification Laboratory, a male immature Blade Eagle was ingested into the right engine striking the fan and causing a single fan blade to fracture near the blade root; the fractured fan blade was contained by the fan case and the remaining fan blades exhibited a combination of leading and trailing edge, as well as blade tip, impact damage, tearing, missing material and bending in the direction opposite rotation. Upon further examination of the engine, it was discovered that two of the thermal management system (TMS) manifold lower aft mounting bracket securing bolts had fractured in shear overstress allowing the bracket to swivel/rotate radially outward. This is one of three mounting brackets that secure the TMS manifold to the engine and prevents excessive moment of the TMS manifold during operation. Along with the broken/sheared TMS lower aft bracket bolts, a crack was visible on the CP-09 fuel line that initiated in fatigue; the CP-09 fuel line is attached to the TMS and contains high pressure fuel. The crack in the CP-09 fuel line was due to necking down of the material as the fuel tube bent and stretched (elongated) under the vibration/cyclic loads after the bird strike and not as a manufacturing issue.

The TMS manifold lower aft mounting bracket securing bolts fractured due to the high impact and vibration loads because of the fan blade release after the bird strike. Subsequently the TMS manifold was allowed to move radially back and forward from the engine in response to the engine vibrations that were recorded on the flight data recorder to be in excess of the 10 cockpit units which is the highest value that the flight data recorder will record. The CP-09 fuel line flexed, bent, and stretched under the cyclical radial motion of the TMS manifold until it cracked due to fatigue spraying high pressure fuel onto the hot engine cases igniting an undercowl fire.

An immature male Bald Eagle has a mean mass of about 4,130 grams (g) (9.1 lbs.). The Federal Aviation Administration large bird ingestion certification test bird weight requirement was 2.75 kilograms (6.05 pounds) for the size of the inlet throat area on the PW1127G-JM geared turbofan engine; thus, the incident ingested bird was larger than the certification basis for the engine.

Verbatim NTSB analysis and probable cause from the NTSB dataset