Multiple-site Fatigue Cracking of Fuselage Structure Due to Improper Rivet Installation.

A large passenger airplane experienced an inflight rapid decompression and was forced to make an emergency landing. Post-accident inspection revealed that a section of the fuselage skin on the top portion of the airplane (crown) had fractured and flapped open during the flight. The National Transportation Safety Board (NTSB) Materials Laboratory examination of the fuselage structure determined that multiple-site damage (fatigue cracking) originated at the skin panel of a lap joint from areas of improperly drilled rivet holes. Fatigue crack growth analysis on the fracture face of the skin panel via quantitative fractography was performed by scanning electron microscopy revealed that cracking started approximately when the airplane entered service. [ABSTRACT FROM AUTHOR]