Materials Examination of the Vertical Stabilizer from American Airlines Flight 587

The first in-flight failure of a primary structural component made from composite material on a commercial airplane led to the crash of American Airlines flight 587. As part of the National Transportation Safety Board investigation of the accident, the composite materials of the vertical stabilizer were tested, microstructure was analyzed and fractured composite lugs that attached the vertical stabilizer to the aircraft tail were examined. This paper discusses the materials testing and analysis, the composite fractures, and resulting clues to the failure events. Findings show that the vertical stabilizer performed in a manner that was consistent with its design and certification. The vertical stabilizer fractured from the fuselage in overstress, starting with the right rear lug while the vertical stabilizer was exposed to aerodynamic loads that were more than certified ultimate load design envelope and approximately twice the certified limit load design envelope.