FAA Issues Final Transport-category Fatigue Rule
Under new final rules issued by the FAA, all transport-category (Part 25) aircraft certified henceforth will have to meet requirements “to prevent catastrophic failure due to widespread fatigue damage throughout the operational life.” The rule also applies to existing Part 25 aircraft operated under Part 121 and 129 regulations with an mtow of more than 75,000 pounds. Manufacturers that certify new Part 25 airplanes will have to include a limit of validity (LOV) that accompanies engineering data used to support the structural maintenance program. Essentially, once an airplane reaches its LOV, it will no longer be able to fly because the LOV is a strict airworthiness limitation. However, the rule does allow any person, not just the manufacturer, to apply for an LOV extension based on maintenance actions that would be incorporated into the maintenance program. The new rule is limited to transport-category turbine-powered airplanes. One change that the FAA made in the final rule was to eliminate “the requirement to evaluate widespread fatigue damage associated with most repairs, alterations and modifications of the baseline airplane structure,” although a change prompted by an airworthiness directive will need to be considered.