Nevergreen
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WSJ-----FAA SETS MANDATORY LIFE LIMIT FOR AIRCRAFT
Federal air-safety regulators, capping years of debates with industry, on Friday issued a rule effectively setting mandatory retirement dates for aging jetliners in order to head off widespread and potentially dangerous metal fatigue.
The Federal Aviation Administration's move locks in the final element of an industrywide campaign, launched in the 1980s, aimed at identifying, repairing and avoiding structural problems before they can lead to in-flight incidents or crashes. But unlike previous directives focused primarily on enhanced maintenance schedules and specific inspection tasks, the latest regulatory action goes beyond preventive efforts.
The FAA for the first time set out maximum safe-operating limits—in terms of total flights or flight hours—for existing models. The rule also requires manufacturers to establish such age-related limits for those planes still undergoing testing or just being designed.
Once these limits are set, airlines won't be permitted to exceed them without relying on special stepped-up inspection and maintenance procedures. In many cases, according to industry officials, the extra costs of complying with such procedures will prompt aircraft retirements.
Affecting more than 4,000 current U.S. commercial planes, the rule builds on more than 100 regulations and safety directives previously issued by the FAA to deal with aircraft structural integrity. FAA chief Randy Babbitt called it "a comprehensive solution to ensure the structural safety of today's airliners and the airplanes of tomorrow."
The sturdiest jetliner model from a structural standpoint, according to the FAA's analysis, appears to be the McDonnell Douglas Corp. DC-9. Under the latest rule, DC-9s would be allowed to remain in service and accumulate as many as 100,000 flights before being subjected to certain enhanced maintenance requirements and practices, versus limits ranging from around 30,000 to 75,000 flights for various Airbus and Boeing Co. models, including MD-80 series aircraft. MD-80s are derivatives of the DC-9. (Airbus is a unit of European Aeronautic Defence & Space Co.)
But the FAA will have to revisit many of these issues as manufacturers introduce more composite parts in new aircraft designs. The agency's document concludes that more study is needed to establish maximum age limits to ensure the structural integrity of those aircraft built with extensive composite parts.
Aluminum fuselages and other metal structures tend to develop small cracks after many years of use, as they constantly expand and contract from pressurization and depressurization during each flight. By themselves, individual small cracks don't pose any hazard. And FAA-mandated inspection schedules already are designed to keep track of areas on planes particularly prone to fatigue.
But according to the agency's latest rule, existing inspection methods can't reliably detect the potential for widespread fatigue damage. A multitude of small cracks, according to the rule, can "link up and grow so rapidly that the affected structure fails before an inspection can be performed." If manufacturers don't establish age limits, on their own, for the validity of their structural-strength analyses, then the agency will impose its limits.
The FAA anticipates extending operating limits for jetliner models on a case-by-case basis, but only after conducting detailed structural analyses that take flight patterns, maintenance schedules and other factors into account.
The phase-in period for the complex new rule will stretch into the next decade. Manufacturers have up to five years to comply with the latest FAA rule, depending on the type of aircraft. Airlines will then have several more years to adjust their maintenance programs, if they hope to extend the life span of certain aircraft
Write to Andy Pasztor at [email protected]
Federal air-safety regulators, capping years of debates with industry, on Friday issued a rule effectively setting mandatory retirement dates for aging jetliners in order to head off widespread and potentially dangerous metal fatigue.
The Federal Aviation Administration's move locks in the final element of an industrywide campaign, launched in the 1980s, aimed at identifying, repairing and avoiding structural problems before they can lead to in-flight incidents or crashes. But unlike previous directives focused primarily on enhanced maintenance schedules and specific inspection tasks, the latest regulatory action goes beyond preventive efforts.
The FAA for the first time set out maximum safe-operating limits—in terms of total flights or flight hours—for existing models. The rule also requires manufacturers to establish such age-related limits for those planes still undergoing testing or just being designed.
Once these limits are set, airlines won't be permitted to exceed them without relying on special stepped-up inspection and maintenance procedures. In many cases, according to industry officials, the extra costs of complying with such procedures will prompt aircraft retirements.
Affecting more than 4,000 current U.S. commercial planes, the rule builds on more than 100 regulations and safety directives previously issued by the FAA to deal with aircraft structural integrity. FAA chief Randy Babbitt called it "a comprehensive solution to ensure the structural safety of today's airliners and the airplanes of tomorrow."
The sturdiest jetliner model from a structural standpoint, according to the FAA's analysis, appears to be the McDonnell Douglas Corp. DC-9. Under the latest rule, DC-9s would be allowed to remain in service and accumulate as many as 100,000 flights before being subjected to certain enhanced maintenance requirements and practices, versus limits ranging from around 30,000 to 75,000 flights for various Airbus and Boeing Co. models, including MD-80 series aircraft. MD-80s are derivatives of the DC-9. (Airbus is a unit of European Aeronautic Defence & Space Co.)
But the FAA will have to revisit many of these issues as manufacturers introduce more composite parts in new aircraft designs. The agency's document concludes that more study is needed to establish maximum age limits to ensure the structural integrity of those aircraft built with extensive composite parts.
Aluminum fuselages and other metal structures tend to develop small cracks after many years of use, as they constantly expand and contract from pressurization and depressurization during each flight. By themselves, individual small cracks don't pose any hazard. And FAA-mandated inspection schedules already are designed to keep track of areas on planes particularly prone to fatigue.
But according to the agency's latest rule, existing inspection methods can't reliably detect the potential for widespread fatigue damage. A multitude of small cracks, according to the rule, can "link up and grow so rapidly that the affected structure fails before an inspection can be performed." If manufacturers don't establish age limits, on their own, for the validity of their structural-strength analyses, then the agency will impose its limits.
The FAA anticipates extending operating limits for jetliner models on a case-by-case basis, but only after conducting detailed structural analyses that take flight patterns, maintenance schedules and other factors into account.
The phase-in period for the complex new rule will stretch into the next decade. Manufacturers have up to five years to comply with the latest FAA rule, depending on the type of aircraft. Airlines will then have several more years to adjust their maintenance programs, if they hope to extend the life span of certain aircraft
Write to Andy Pasztor at [email protected]
