T. E. Collins, The Boeing Company, Huntington Beach, CA; B. Tucker, United Space Alliance, KSC, FL; R. Russell, NASA, KSC, FL
In the early part of the Space Shuttle Columbia accident investigation numerous scenarios were being investigated. One such scenario was loss of a wing leading edge access panel, known as a carrier panel. This scenario was supported by the finding of several carrier panel attach fasteners with apparently brittle fractures. This finding appeared to support a scenario wherein some pre-existing condition such as stress corrosion or counterfeit fasteners may have weakened this vital link.
The failure analysis conducted on recovered panel attach fasteners and spares drawn from stock yielded the finding of several failure mechanisms including brittle fracture at high temperature. With the final conclusion that there was no pre-existing condition and all failure modes could be explained as a result of the accident not a cause.
During the initial phases of the Shuttle Columbia investigation, one scenario analyzed was loss of a carrier panel behind the wing leading edge. Observations of carrier panel debris noted a brittle fracture appearance on several attach fasteners. Although later determined not to be causal, investigation into these fastener failures was interesting nonetheless.
