... the carrier was found to have operated six jets with cracks in their fuselage. They later found 43 other jets that flew more than 100,000 trips over several years while out of compliance.
ATS was charged with replacing skin panels in order to satisfy safety directives that required repetitive inspections. But ATS decided that it could not perform the work as prescribed and suggested its own workaround to Southwest. Southwest approved that solution but failed to inform the FAA about it.
Part of the work involved a process known as shoring, which is how mechanics secure the aircraft frame while skin panels are changed. In addition, the inspectors found that ATS' mechanics didn't always apply rivets to refasten the skin panels within the 20 hours prescribed by Boeing, the plane manufacturer. The rivets must be applied in that timeframe to ensure that sealant doesn't leak out, creating a gap between the skin and the frame of the airplane.
In the worst-case scenario, faulty work could lead to metal fatigue, corrosion or other deterioration of the aircraft's skin. Even tiny cracks in a jet's skin can expand as the plane's fuselage expands and contracts during thousands of pressurization cycles.
http://www.dallasnews.com/business/...ines-facing-FAA-safety-investigation-6554.ece
