Multi-Site Damage 

MSD – Multi-Site Damage is the simultaneous presence of multiple fatigue cracks in the same structural element on an aircraft. Such cracking can occur at adjacent features, such as fastener holes. The presence of MSD can adversely affect the structural integrity of the element and lead to failure. Interaction between adjacent cracks in MSD can have a significant impact on crack growth rates. MSD was the cause of the Aloha Airline Boeing 737 cabin rupture in the 1980s.

For more information on the analysis of MSD see:

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