Section 188.8.131.52. Initial Damage Assumptions
JSSG-2006 paragraph A3.12.1 assumes that any fastener hole in
the structure can be marginal and can have an initial damage equivalent to a
0.005 inch radius corner flaw. Thus,
the guidelines requires assuming that this flaw exists at each fastener hole
within the structure at the time of manufacture. Since the 0.005 inch size is based on limited data, the
contractor may provide data representing his own manufacturing quality and
negotiate with the Air Force for a smaller size of the apparent initial flaw to
represent marginal hole quality.
The most critical location for the initial flaw should be
determined by reviewing all elements of the structure and considering features
such as edges, fillets, holes, and other high stressed areas.