The FAA is requiring manufacturers and airlines to intensify and streamline inspections of the metallic skeleton and skin of aircraft, estimated to cost the industry some $3.6 million. The regulation has been in the works for years and pulls together related rules and directives issued by the agency on fatigue cracking, which is mainly caused by repeated changes in pressurization during flight.
Structural fatigue and questions about FAA oversight have arisen in a handful of incidents in recent years. At issue are tiny cracks, some of them visible, that often form on a plane as it ages. Individually, the cracks are of little concern. But they can weaken an aircraft's structure if permitted to spread and link with other cracks.
More than 4,100 planes registered to fly in the United States are affected by the new rule. There have been several instances in the past few years involving fatigue. The FAA said it is working with European safety officials to harmonize regulations. European Aviation Safety Agency is currently working on its own fatigue directive.
Manufacturers have between 18 and 60 months to comply with the new FAA rule, depending on the plane involved. Airlines then have another 30 to 72 months to incorporate the changes into their inspection routines.