By Andy Pasztor
U.S. aviation regulators on Monday will propose mandatory inspections and, if necessary, replacement of suspect parts on nearly 1,600 jetliners to prevent potentially catastrophic failures.
The pair of proposed Federal Aviation Administration safety directives, related to certain Boeing Co. and Embraer SA jets and slated to be formally published Monday in the Federal Register, are unusual because they are each intended to counter a single defect that can result in such a serious problem.
Most essential systems on commercial jets have backups, so a single-point failure or malfunction can't cause a crash. In both of the documents, however, the FAA says a single defective component type has the potential to immediately end safe flight. The agency isn't ordering immediate fixes, however, which means officials have determined the hazards aren't imminent and don't require emergency action.
The FAA is moving to require U.S. operators of certain versions of the popular Boeing 737 model to check for possible corrosion of attachments for the horizontal stabilizer, part of the tail section.
According to the agency, because of a manufacturing mistake that left some parts without the necessary protective finish to guard against corrosion, certain bushings can crack. That can result in structural failure and possibly "departure of the horizontal stabilizer from the airplane," according to the FAA, "which can lead to loss of continued safe flight."
The proposed directive covers some 1,400 of the 737 models, beginning with the 737-600 version and a number of later variants.
The FAA document indicates the problem was discovered after production of the affected stabilizers and the agency wants airlines to detect and correct possible structural cracks.
A separate proposed mandate, applying to airliners manufactured by Brazil's Embraer, the world's third-largest plane maker behind Boeing and Airbus Group SE, covers a total of 197 twin-engine Embraer 170 and 190 regional jet models.
The FAA has determined that certain defective valves, prone to cracking, could "result in dual engine in-flight shutdown" on the affected aircraft. The agency envisions giving U.S. carriers three months to comply with some of the mandates.
Both manufacturers raised the safety issues previously in separate safety bulletins. Last year Brazilian air-safety regulators mandated some of the fixes, but didn't include certain 170 models in their order.
Pending public comment, the FAA now wants to make all of the previous voluntary fixes mandatory for U.S. operators while expanding beyond Brazil's directive.
Foreign airlines and regulators typically follow the FAA's lead.
The agency's proposals don't mention any accidents or incidents stemming from the manufacturing defects.
Write to Andy Pasztor at email@example.com